DE102005021726A1 - Module for a brushless electric motor and method of making the same - Google Patents

Abstract

The invention relates to a module (11) for a brushless, multi-phase electric motor. The module (11) has a supporting body (12) made of plastic, the connector (19-22), supports (25-27) for mounting a Hall sensor has, which are interconnected via interconnects. According to the invention, the module (11) is manufactured using an MID technology.

Description

Territory of invention

The The invention relates to a module for a brushless one Electric motor with a supporting body, plugs, a receiving element for a sensor, in particular a Hall sensor, and printed conductors according to the preamble of patent claim 1. Furthermore, the invention relates to a method for producing a module for an electric motor according to the preamble of claim 8.

background the invention

From the publication DE 103 15 871 A1 The applicant is a brushless DC motor is known in which a housing of the DC motor is axially closed with a lid. The lid is integrally formed with a plug module having a support body made of a heat-resistant plastic. Printed conductors, which serve as a carrier of electrical signals and connectors with connections for phases of a stator of the DC motor, as well as connectors for connections with Hall sensors are formed by a stamped grid, which are (all sides) overmolded by the plastic of the Tragkör pers. The plug module may additionally have a centering collar for a bearing seat and reinforcing rings for receiving forces of fastening screws.

Further prior art is for example from the documents DE 297 24 873 U1 and DE 198 15 964 A1 known.

Task of invention

• – der Herstellungsmöglichkeiten,
• – der Integration und Bereitstellung der Leiterbahnen,
• – der Bauraumgröße,
• – der Komplexität der Geometrie des Moduls,
• – der Kosten

verbessert ist.The invention has for its object to provide a module for a brushless electric motor, in terms of

• - the manufacturing possibilities,
• - the integration and provision of printed conductors,
• - the installation space size,
• - the complexity of the geometry of the module,
• - the cost

is improved.

Summary the invention

According to the invention Problem solved by the features of independent claim 1. Further Embodiments of the invention will become apparent from the dependent claims 2 to 7th

According to the invention, the module has a Supporting body, which is formed with plastic. Such a support body is in a simple and inexpensive way can be produced under the known production methods, preferably an injection molding process is used. The support body is used the reception, the attachment and the support of the others, below said components, wherein the plastic suitable for the respective Purpose chosen may be, for example, temperature resistant and / or oil or lubricant resistant. Furthermore, the module according to the invention has plug, the electrical Allow connections of the module with adjacent components. For example can the plugs of an electrical power supply for phases serve the stator of the electric motor. Furthermore, a power supply for that Module assigned sensors via the plugs are made. Alternatively or additionally, over the Plug an electrical signal from the module "tapped", which is assigned by the module Sensors is generated.

Additionally owns the module according to the invention at least one receiving device for connecting a sensor, in a sensor, for example, cohesively, positively, frictionally or via a Latching or snap connection can be added and maintained.

conductor tracks the module according to the invention are with the plugs, sensors and electrical components of the Module connected or connectable.

According to the invention, the module is manufactured using an MID technology. For such a preparation, various materials can be used, which are, for example, high-temperature or structural thermoplastics, which are provided with a wide variety of surface coatings. The materials for the support body are thereby selected with regard to the processing and service temperatures, a sludge protection, the mechanical and electrical properties, the spray and metallization and in terms of cost. In particular, polypropylene, acrylonitrile-butadiene-styrene, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyphenylene sulfide, polysulfone, polyethersulfone, polyetherimide and liquid crystal polymer, also referred to as "commodity thermoplastics", "technical thermoplastics" or "HT-thermoplastics", are used as materials for the supporting body. be designated. The surfaces for the MID technology can be provided with surfaces customary in printed circuit board technology, for example tin, lead, gold (galvanic or chemical) or Ni ckel. According to the invention, the support bodies, which replace conventional printed circuit boards ago, can be arbitrarily shaped by using the MID technology. Furthermore, completely new functions are possible, whereby a miniaturization of the modules is possible. Characterized in that further components are integrally integrated into the support body, additional mechanical components can be saved, which minimizes the production cost, simplifies installation and increases reliability. Materials used for an MID technology may include: U. Flammhemmend without additives, can be easily recycled and are therefore environmentally friendly. By using an MID technology, additional components and functions can be integrated into the carrier body, unlike conventional printed circuit boards. These are, for example, reinforcing ribs or stiffeners, cooling fins, sockets for receiving components or plugs, screwing elements, housing functions, snap connections for connection to further components, switches, shielding surfaces, sealing elements, integration of passive components and / or active components such as microcontrollers, operational amplifiers , Bearing seats u. Ä. In addition, using the MID technology, a simplified and / or improved interconnect unbundling take place, wherein at crossing points of individual conductor paths, u. U. using a "jumper", targeted electrical connections can be avoided or can be created by electrical contacts crossing points or branch points.

For the embodiment according to the state of Technology find punched grid insert, the two-sided with plastic have to be overmoulded at least in subareas. This results in an increased thickness dimension a module because the punched grid applied to a base layer is provided and provided with a cover layer of plastic, so that results in a three-layer structure. According to the invention Trace over the MID technology applied to a plastic layer of the support body, without an additional third Layer, for example made of plastic, is mandatory. If the conductor track is a foil which is impressed on the carrier body, so this can with a thickness of z. B. 30-50 microns, so that an overall very small thickness dimension results. hereby The module may be better or closer to associated components of the Electric motor to be mounted.

Farther requires for the embodiment according to the state the technology of the connection of the stamped grid, that the sheet metal of the Punching grid must be reshaped to the contour of the punched grid adjust the assigned contour of the PCB. For one Complex structure of the contour are complex forming processes required for the a lack of precision to an insufficient connection of the punched grid to one underneath lead lying PCB can. The use of MID technology is independent of the contour of the substrate, so that the manufacturing cost of the complexity the contour does not or only insignificantly depends.

• – Laser-Direct-Structuring,
• – Laser-Substractive-Structuring,
• – 2-Komponenten-Spritzguss,
• – ein Heißprägen,
• – ein Maskenbelichtungsverfahren,
• – eine Hinterspritzung von Folien.

Under the MID technology ("molded interconnect devices") are understood injection molded plastic parts, which carry electrical conductors and represent depending on the contour of the support body two- or three-dimensional circuit boards. Using the MID technology, electrical connections can also be led out of an existing plane at arbitrary angles, so that electrical components can be assigned to the conductor tracks in a wide variety of installation space directions. To produce fine two- or three-dimensional strip conductors, the following methods are preferably used according to the invention:

• - Laser Direct Structuring,
• - laser-subtractive-structuring,
• - 2-component injection molding,
• - a hot stamping,
• A mask exposure method,
• - An injection back of foils.

at A laser direct-structuring becomes the one with a metal complex provided plastic with a laser described. This leads to a local Akti vation of the metal complex. The plastic can then be connected the local Activation in chemical baths metallized.

deviant For this purpose, the Laser-Substractive-Structuring first a area of the plastic body chemically activated and metallized. The structuring takes place then by laser ablation and / or exposure with subsequent etching processes, whereby the tracks are separated.

at a 2-component injection molding are in a two-stage injection process two different plastics so injected into each other, that at the surface the pattern of the trace of the two components arises. In the case, that for a first plastic a chemically well metallisierbarer plastic chosen will, while for the second plastic is used a non-active plastic is generated a chemical metal deposition on the plastics directly one corresponding conductor track structure.

Subsequent to the previously described use of the MID technology, an assembly of further electrical and / or mechanical components takes place mente. As mounting techniques can be a wire bonding (thermosonic bonding, ultrasonic bonding) or a "flip-chip" (adhesive with isotropic conductive adhesive, anisotropic conductive adhesive and non-conductive adhesive; soldering, for example, leaded solder with or without flux, lead-free solder with or without flux). The main differences between wire bonding and flip-chip are space requirements, process flow and stability requirements. Wire bonding takes up a lot of space through the outgoing wires, has a sequential connection process of each terminal, and shows good stability through the "moving" electrical wire connections. The main advantage of the flip-chip connection process is the space savings and the parallel connection of all connections in one step.

At the Wire bonding process, the chip pads of the on the substrate glued chips with a very fine metal wire (usually Au or Al with diameters in the range 25-70 μm) with the conductor tracks connected to the substrate.

These Connections are made by locally welding the wire to the underlying one Metallization. The required energy is either pure through Ultrasonic vibrations of the bonding tool or even additional Warming introduced. While Al wires Bonding with pure ultrasound at room temperature are temperatures for Au wires from above 100 ° C required, what the use on the plastic substrates by their bad heat conduction and easier to mold at higher temperatures.

The transfer of the wire bonding process on MID parts established on planar substrates essentially critical in two respects. To a good one To achieve bondability are a good ultrasonic transmission and not too rough metal layers required. The good ultrasound introduction requires a "hard" edition of the bonding tool. This requires on the one hand a good fixation of the component itself, which is too expensive for these mostly small MID components Guide brackets can. On the other hand, a sufficient Rigidity of the component itself, which is due to the nature of the component used plastic, the layout and the metallization influenced becomes.

The Demand for smooth metal layers is in contradiction to good adhesion of the metal layer on the plastic surface. Just a certain roughness guarantees sufficient adhesion. In addition, the lead different metallization process to different roughness Surfaces. LDS layers are currently hardly industrially bondable, however are running by varying laser parameters and metallization achieved strong improvements. For two-component injection molding and Laser Substractive Structering Method will be the appropriate one Plastic directly chemically activated and metallized, causing the generation bondable layers with enough small roughness allowed.

At the Wire bonding brings the use of injection molded parts as mounting substrates also advantages. It can z. B. simply cavities can be generated in which the chips are mechanically well protected and the Glob Top can be applied in a simple and space-saving way. Glob Top is the potting material with which chip and bonding wires are cast to stabilize and protect them. For planar substrates is common a two step process is necessary, with the chip around first a dam is applied, which then the wide flow of the over the Chip and wires Distributed glob tops prevented.

at The flip-chip techniques flip the chip over and then on the bottom electrical connections directly to the geometric connected corresponding conductor tracks. The mechanical attachment must therefore be in the same spatial Range as the electrical connections are made. For most Method (soldering and ICA = Isotropic Conductive Adhesive, isotropic conductive adhesive) The two steps are done separately by first the electrical Links through small hills made of solder or conductive Glue generated and in the process (solder or harden) the contacts are made. In the second step, then Chip and connectors mechanically stabilized and protected with an underfill. In ACA and NCA process (ACA = Anisotropic Conductive Adhesive, Anisotropic conductive adhesive and NCA = NonConductive Adhesive, Non-conductive Glue) these two steps are united in one by the on the entire chip area applied adhesive during the curing process generates both functions. In both cases are electrically conductive Elevations (bumps) on the chippads and / or the tracks necessary to the electrical To ensure contact. Included in the ACA process the adhesive is a few conductive Particles which lead to a conductive connection only where they are "pinched" during the assembly process by the bumps. The NCA is an electric one non-conductive adhesive, which during curing with pressure and heat the direct mechanical and electrical contact of the bumps to the counter metallization guaranteed.

For the NCA flip-chip mounting on the MID substrates in particular chips can be used, which are provided with so-called Au Stud bumps. The latter are generated by means of a standard Au wire bonding process by placing the wire after setting the first bond immediately cut off. In a second step, all pieces of wire are pressed at the same height.

On the MID substrate tracks are generated, which under the chip lead to the corresponding connection pads. These can be on Also insert MIDs into hollows or around edges so that chips sink or spatially can be arranged three-dimensionally. The NCA assembly process has the advantage of a one-step process: contacting, fixation and first protection in one step. After applying the glue at the chip position, the inverted chip is pressed into the glue so that the stud bumps are pressed onto the appropriate tracks and generate the electrical contact. While maintaining the Pressure and temperatures in the range 150-200 ° C cures the adhesive depending on the type within 10-30 seconds. The occurring during curing shrinking forces cause both a stable electrical and a mechanical Connection of the chip. Furthermore, that is already down directed chip surface poured in and thus protected.

Corresponding In a further embodiment of the invention, the module has at least a carrier on. The carrier is integrally connected in one end region with the support body. Preferably, the carrier integral with the support body formed and common, for example, in the injection molding process with the support body produced. Alternatively, a carrier can be glued to the support body or be merged. The carriers can already during the manufacture on measure and Orientation or in a downstream production step, so that independent from an assembly of the carriers according to the state the dimensional accuracy of the technique and orientation of the carriers to each other and to the module is ensured in a simple manner.

In the support body opposite end region instructs the wearer a recording device for a sensor on. In the receiving device is a sensor, in particular a Hall sensor, can be used, wherein the sensor by the receiving device and the carrier across from the support body is held in a fixed position. The connection between receiving device and sensor can over be secured a fastener, form fit, done by friction or the sensor may be in the carrier latch or snap. The carrier may further be via suitable guide channels or Mounts for Have lines, which are connected to the sensor. Here, the channels can one Protective function against mechanical Ensure contamination or contamination with dirt or oil.

Several carrier are essentially oriented parallel to each other, so this parallel to a longitudinal axis of the electric motor can be arranged.

The carrier on the one hand serve the sensors spaced from the support body to position at a measurement location. For example, you can the carriers in suitable grooves of a stator of the electric motor extend to in areas where there is a magnetic field to be detected. Of Further, an interaction of other electrical components and the traces are avoided with the sensor in that the sensor over the carrier from the support body is relocated away. The carriers are also advantageous in terms of dynamic stress or a vibration protection of the sensor and can with regard to the mechanical Properties, in particular with regard to the flexural rigidity, in such a way be designed to have a favorable vibration behavior established.

For a further education the module according to the invention has the support body Centering on. these can For example, in the form of center holes, in the passport or centering pins of adjacent components, such as a stator of the electric motor o. Ä. enter. Alternatively or in addition can the support body Having centering pins in the appropriate fitting holes of the adjacent Enter components.

For a development of the invention, the support body in plan view approximately U-shaped with a base leg and two side legs or "bridge-like" is formed. Accordingly, the support body surrounds, deviating from the prior art according to DE 103 15 871 A1 the longitudinal axis of the electric motor is not completely in the circumferential direction, but only for a circumferential angle of about 180 °. This embodiment of the invention is based on the finding zugrun that, in particular for a three-phase DC motor in which each phase is guided on circumferentially opposed windings, the Hall sensors need not be distributed over a circumferential angle 360 °, but that it may be sufficient , if the Hall sensors are distributed over an angle <180 °. Accordingly, the module may be formed with respect to the prior art with half the circumferential extent, the Hall sensors are arranged differently from the prior art on the side facing the terminals of the longitudinal axis of the electric motor.

Furthermore, the plugs extend in the plane of the U from the base leg vertically thereto, while the carriers extend vertically to the support body. The base legs and the sei thigh define a recess on the inside, through which the longitudinal axis of the electric motor passes and which has a diameter which correlates with the outer diameter of a rotor or a rotor associated shaft of the electric motor.

A improved, multifunctional design of the module, if an extra Recording device for a temperature sensor is provided.

Preferably the module can be used together with SMD Hall sensors, For example, if the axial stray field of the main magnet or an additional one axially arranged sensor magnet to be scanned. In this Case, it is advantageous if the carriers and sensors on the side the interconnects are arranged, u. U. together with a suitable Wiring for the Hall sensor. This allows a two-sided assembly of the Module with a necessary via from the one on the other side can be avoided.

alternative can the wired Hall sensors and possibly temperature sensors by means of a "through hole" montage through the supporting body be passed through, so that the carrier and sensors are located on the side of the supporting body, which the conductor tracks opposite.

One Method for producing a module for an electric motor is characterized by the features of claim 8. First, a support body with the carriers one piece in an injection molding process from a temperature-resistant plastic, See, for example, the materials listed above. The tracks are using at least one MID technology on the support body applied, cf. the aforementioned methods. Plug, the electrical Allow connections of the module to adjacent components, For example, electrical connections for sensors, electrical power supplies are on the support body attached. Therefor Already during injection molding a suitable receptacle in the support body be provided. Alternatively or additionally, such images can be retrofitted in the supporting body be introduced. Subsequently become the conductor tracks and / or support body with electrical components equipped, and Sensors become in the carriers, for example, form-fit, frictionally engaged, over one Locking connection or over a snap connection, over Fastener or material fit, attached. The tracks, the plugs, the sensors and / or the electrical components are electrically connected. Such a connection can be done by wiring, soldering, Bonding, for example, with an SMD adhesive done.

Short description the drawings

Further Features of the invention will become apparent from the following description and its associated Drawings in which embodiments of the invention are shown schematically. Show it:

1 an inside view of a lid formed module according to the prior art;

2 a side view of the module according to the prior art accordingly 1 ;

3 an inventive module at substantially 1 corresponding viewing direction (top view);

4 the module according to the invention according to 3 in side view and

5 the module according to the invention according to 3 and 4 in bottom view.

Full Description of the invention

This in 1 shown connector module 1 consists of heat-resistant plastic, with which a likewise heat-resistant stamped grid is molded. The punched grid serves as a current path and connects plugs 2 with connections 5 for phases of the stator of a brushless DC motor (not shown) (BLDC motor).

Another connection exists between other connectors 3 and not shown other terminals 6 for Hall sensors 4 , which serve the electrical commutation of the BLDC motor. The plugs 2 . 3 and the connections 5 . 6 are components of the stamped grid. The Hall sensors 4 and the other connections 6 are heat-resistant connected by welding.

The module 1 has a centering collar 7 which serves to center it with respect to a motor housing, not shown, of the BLDC motor. In this motor housing, the stator of the BLDC motor is also centered. Because the module 1 and the stator are rotationally fixed relative to the motor housing, is an exact rotational and radial position of the terminals 5 . 6 guaranteed.

In the module 1 is coaxial with the centering collar 7 a camp seat 8th arranged in which a motor bearing is pressed or glued. To stabilize tion of the area of through holes 9 against the screw force of fastening screws are not shown, overmolded or joined reinforcing rings provided. The plugs 2 . 3 are elements of the connection module 10 ,

Notwithstanding that in the 1 and 2 illustrated module 1 is the module according to the invention 11 with a supporting body 12 formed, which is approximately U-shaped with a base leg 13 , from which are perpendicular and parallel two side legs 14 and 15 extend. The supporting body 12 forms a circular recess on the inside 16 through which a rotor or a shaft passes and which is oriented approximately coaxially with the longitudinal axis of the electric motor. The support body is approximately plate-shaped with one in the region of the base leg 13 arranged on the edge continuous thickening 17 , In the thickening 17 are parallel recordings 18 provided in which plug 19 - 21 are held as well as plugs 22 , where the plug 19 - 21 allow a connection of a power supply for the different phases of the electric motor, while the plug 22 enable a voltage supply and / or a tap of the signals from temperature sensors and / or Hall sensors.

The supporting body 12 has centering holes distributed circumferentially about the longitudinal axis of the electric motor 23 . 24 , by means of which the module 11 can be clearly defined with respect to adjacent components and with respect to the longitudinal axis.

Furthermore, are fixed to the support body 12 three carriers 25 . 26 . 27 connected, which are vertical to the drawing plane and to the supporting body 12 extend and in the circumferential direction at the same distance from the longitudinal axis, each offset by a circumferential angle of approximately 60 ° to each other, are arranged. The carriers 25 - 27 are elongate with approximately rectangular cross-section, wherein the longitudinal extent is two to three times as large as the maximum cross-section of the carrier 25 - 27 , In which the support body 12 opposite end region have the carrier 25 - 27 each a receiving device 28 . 29 . 30 , by means of which in each case a Hall sensor with respect to the carriers 25 - 27 and thus can be held against the support body. On the carriers 25 - 27 opposite side has the support body 12 conductor tracks 31 and electrical components 32 that work in concert with each other, with the Hall sensors and plugs 19 - 21 as well as the plugs 22 are connected. Another carrier 33 with recording device 34 can be a temperature sensor 35 hold, the carrier 33 in the circumferential direction approximately opposite to the carrier 25 is arranged at approximately the same distance from the longitudinal axis.

5 shows the bottom of the module 11 with tracks 31 and electrical components 32 , The tracks 31 are on the support body 12 made of plastic by MID technology (molded interconnect devices), for example, with a hot stamping, a laser structuring and / or the two-component injection molding. In the supporting body 12 or the conductor tracks 31 Contacts for the temperature sensor and the Hall sensors are integrated, so that these with the tracks 31 can be soldered. The module 11 is suitable for both a brushless roller rotor motor and a brushless pancake motor. There are variants for 1-, 2-, 4-phase o. Ä. Electric motors possible. Furthermore, unlike the illustrated embodiment, a different number of Hall sensors is conceivable, both for a 3-phase design and for a different-phase design. Furthermore, the electrical wiring can be omitted or varied by resistors and capacitors. For example, in addition to passive components and active components, such as microcontroller, operational amplifier u. Ä. Used. The Hall sensors can on the one hand by Hall sensor images in the carriers 25 - 27 and / or additional plastic covers are protected. The arrangement of the connector pins is variable. In addition, the different functional levels are variable, ie different from the apparent for the illustrated embodiments contours more complex, dreidi dimensional structures are conceivable. Finally, the integration of ancillary functions such as a bearing seat, sealing rings u. Ä., conceivable.

1

module

2

plug

3

plug

4

Hall sensor

5

connection

6

plug

7

spigot

8th

motor bearings

9

Through Hole

10

connection module

11

module

12

supporting body

13

base leg

14

side leg

15

side leg

16

recess

17

thickening

18

admission

19

plug

20

plug

21

plug

22

plug

23

centering

24

centering

25

carrier

26

carrier

27

carrier

28

recording device

29

recording device

30

recording device

31

conductor path

32

electrical module

33

carrier

34

recording device

35

temperature sensor

Claims (9)

Module for a brushless electric motor with - a support body formed with plastic ( 12 ), - plugs ( 19 - 22 ), the electrical connections of the module ( 11 ) with adjacent components, - at least one receiving device ( 28 . 29 . 30 ) for connecting a sensor and - printed conductors ( 31 ), which with the plugs ( 19 - 22 ), the sensors and electrical components of the module ( 11 ) are connected or connectable, characterized in that the module ( 11 ) using an MID technology. Module according to claim 1, characterized in that supports ( 25 - 27 ) are provided, which - in one end region cohesively with the supporting body ( 12 ), - in a opposite end portion a receiving device ( 28 - 30 ) for a sensor and - are oriented substantially parallel to each other. Module according to claim 1 or 2, characterized in that the supporting body ( 12 ) Centering elements (center holes 23 . 24 ) having. Module according to one of the preceding claims, characterized in that - the supporting body ( 12 ) in plan view approximately U-shaped with a base leg ( 13 ) and two side legs ( 14 . 15 ) or bridge-like, - the plug ( 19 - 22 ) in the plane of the U of the base leg ( 13 ) extend vertically to the latter, - the beams ( 25 - 27 ) vertical to the plane of the U of the support body ( 12 ) and - the base leg ( 13 ) and the side legs ( 14 . 15 ) inside a recess ( 16 ), which correlates with the outer diameter of a rotor or a shaft of the electric motor associated with the rotor. Module according to one of the preceding claims, characterized in that an additional receiving device ( 34 ) is provided for a temperature sensor. Module according to one of the preceding claims, characterized in that the supports ( 25 - 27 ) and sensors on the side of the support body ( 12 ) are arranged, on which the conductor tracks ( 31 ) are located. Module according to one of Claims 1 to 5, characterized in that the supports ( 25 - 27 ) and sensors on the tracks ( 31 ) are arranged opposite side. Method for producing a module ( 11 ) for an electric motor, in particular according to one of claims 1 to 5, characterized by the following method steps: - a supporting body ( 12 ) with carriers ( 25 - 27 ) is produced in one piece in an injection molding process from a temperature-resistant plastic, - conductor tracks ( 31 ) are applied to the support body using at least one MID technology ( 12 ), - plug ( 19 - 22 ), the electrical connections of the module ( 11 ) with adjacent components, are on the support body ( 12 ), - printed conductors ( 31 ) and / or supporting body ( 12 ) are connected to electrical components ( 32 ), - the printed conductors ( 31 ), the plugs ( 19 - 22 ), the sensors and / or the electrical components ( 32 ) are electrically connected. Method of manufacturing a module according to claim 8, characterized in that sensors on the supports ( 25 - 27 . 33 ) are attached.