DE102009049737A1 - Stator arrangement for brushless direct current motor utilized for driving ventilator, has connecting device i.e. contact pin, embedded in groove insulator, and collar formed around device by groove insulator - Google Patents

Abstract

The arrangement (5) has multiple stator windings arranged on a stator core. A groove insulator is arranged at the stator core, and a printed circuit board (22) is arranged in a separate housing (21). The stator windings are connected with the printed circuit board by a connecting device (31) i.e. contact pin, which is guided into the housing by a pushing opening. The connecting device is embedded in the groove insulator, and a collar is formed around the connecting device by the groove insulator. The groove insulator is made of plastic.

Description

The invention relates to a stator assembly, in particular for a brushless DC motor, having a stator core on which a plurality of stator windings are arranged, with a slot insulation, which is arranged on the stator core, with a printed circuit board, which is arranged in a separate housing connected to the stator core , wherein at least one stator winding is electrically connected via a connecting means with the circuit board and the connecting means is guided through a passage opening in a housing wall.

Such a stator arrangement is used, for example, for a brushless external rotor motor for driving a fan. Fans are exposed to moisture, chemicals, dust or other adverse conditions in many areas. In particular, the electrical contacts of the stator and electronic components on a printed circuit board arranged on the stator are endangered by corrosion or short circuit.

To protect the electronics, the circuit board is arranged for example in a separate housing. Attempts are made to seal openings in the housing, through which, inter alia, cables and electrical connections are made, with rubber grommets or similar sealing means. However, these sealants are either not sufficiently tight or must be laboriously mounted by hand, which prevents automatic production of the stator assembly and the motor and thus increases the manufacturing cost.

Another approach to protect the electrical system is in the DE 203 02 576 U1 shown. In this case, the stator assembly is arranged together with the circuit board and the entire control electronics in a closed housing, which is completely sealed against the environment. A disadvantage of this arrangement, however, is that a housing wall runs in the air gap between the stator and the rotor. As a result, the air gap must be correspondingly large, so that the efficiency is reduced. In addition, the manufacture of the fan is complicated and expensive.

The object of the invention is therefore to provide a stator assembly of the aforementioned type, which is better protected against environmental influences and easy and inexpensive to produce.

This object is achieved in that the connecting means is embedded in the slot insulation, that by the slot insulation, a collar is formed around the connecting means and that the collar seals the through-hole in the housing wall dust and liquid-tight.

The collar around the embedded in the slot insulation connection means serves as a seal for sealing the passage opening in the housing wall. When introducing the connecting means into the push-through opening, the opening is thereby automatically sealed by the collar. For this purpose, a seal, such as rubber, molded or fastened to the collar. However, the invention does not necessarily require the use of such additional sealants. Rather, their use is limited to applications in which a different choice of material of slot insulation and housing can form crevices at the interface. Since the connecting means is embedded in the slot insulation, an absolutely tight connection is ensured here as well, so that a dust and liquid-tight seal of the housing is easy to implement. In addition, the collar provides electrical insulation of the connecting means relative to the housing wall.

Thus, the collar closes the passage opening tight, it is expedient if the collar is slightly larger than the opening itself.

Alternatively or additionally, the collar may be connected to the housing wall. For this purpose, the collar can be welded, pressed or glued within the push-through opening with the housing wall, so that a firm connection between the collar and the housing wall is formed.

It is particularly advantageous if the collar is ultrasonically welded to the housing wall. The collar is easily melted and it is achieved an absolutely tight and cohesive connection to the housing wall.

Particularly advantageously, the housing wall is made of a plastic, in particular the same plastic as the slot insulation, so that the two parts homogeneously connect by ultrasonic welding.

The slot insulation is preferably made of plastic and is expediently injection-molded, wherein the connecting means is inserted, glued or latched in a corresponding opening of the slot insulation.

Preferably, the connection means is embedded or overmolded in the slot insulation by the injection molding process. By injection molding, the slot insulation and the collar around the connecting means are simple and inexpensive to produce. In addition, the injection molding has the advantage that the collar can have any shape, so that, for example, angular insertion openings can be sealed.

The embedded in the slot insulation connection means may be an arbitrarily shaped conductor, which can provide an electrical connection between the stator winding and the printed circuit board. An advantageous embodiment provides that the connecting means is designed as a contact pin. The contact pin may have any profile, but this is preferably round or square.

The contact pin has expediently two free ends to which it is contactable. At one of these ends the stator winding and at the other end the circuit board is connected.

In an advantageous embodiment of the invention, the contact pin is formed substantially U-shaped with two legs. The first leg is designed for contacting the stator winding and the second leg for contacting the printed circuit board. The arc of the contact pin is embedded in the slot insulation. The shape of the bow plays no role and can be, for example, round or square.

Since only one leg of the U-shaped contact pin to engage in the housing of the circuit board, the two legs are preferably different lengths. The collar formed by the slot insulation is arranged on the longer leg.

The slot insulation is generally formed in one piece and is molded directly onto the stator core.

In a preferred embodiment of the invention, the slot insulation is formed in two parts and the two Nutisolationsteile are axially pushed onto the stator core. This allows a much shorter cycle time in injection molding, since no stator core has to be preheated to the process temperature. Furthermore, the injection molds of the two parts are much easier and cheaper to produce.

The two slot insulation parts are pushed axially from opposite sides onto the wound stator core. The two slot insulation parts are fixed by the stator windings on the stator core. In addition, the two slot insulation parts can be connected to one another, for example, by a latching, plug-in or adhesive connection.

The slot insulation or at least one groove isolation part preferably has a bearing receptacle in which at least one bearing can be used to receive a shaft.

The housing in which the printed circuit board is arranged preferably has a housing body, which has a housing opening for inserting the printed circuit board, which housing opening can be closed or closed in a dustproof and liquid-tight manner by a cover plate.

The housing body further preferably has a seating opening for placement on the slot insulation. In particular, preferably, the bearing receptacle has a notch or taper, to which the housing body can be placed in a form-fitting manner. The shape of the attachment hole does not matter and may be circular or square, for example.

Conveniently, the housing body is connected to the slot insulation. The connection can be done for example by gluing or welding. Particularly expedient is the housing body made of plastic, wherein the connection takes place by ultrasonic welding simultaneously with the connection of the collar.

The housing body and / or the slot insulation preferably have at least one additional connecting element. Particularly advantageously, these connecting elements are designed to correspond or complementary and allow the sake of manufacturability, a free access to the connection point, such as from the housing opening.

Additionally or alternatively, the housing body and the slot insulation can also be connected to one another via a screw connection. Preferably, the screw is designed so that the screw is screwed in the stator and there is no opening at the interface between the housing body and the slot insulation.

The cover plate closes the housing opening dust and liquid-tight. It is advantageous if the cover plate is at least partially made of plastic.

For tight attachment of the cover plate, the cover plate may for example be glued or welded to the housing body or attached by a clip connection.

The housing preferably has a plurality of fastening elements, which are firmly connected to the housing body or formed integrally therewith. The fasteners allow attachment of the stator assembly and the motor constructed therewith. For this purpose, the fasteners may for example have internal thread for receiving screws or bolts.

The invention is explained in more detail below with reference to an embodiment with reference to the accompanying drawings.

It shows:

1 a cross section through a fan with a stator assembly according to the invention,

2 a cut through the fan of 1 along the line DD,

3 a stator core according to the invention with windings, contact pins and two-part slot insulation,

4 a side view of the stator core of 3 .

5 another sectional view of the engine of 1 through a contact pin and

6 an enlarged detail of the 5 in the area of the contact pin.

The 1 shows you as a whole 1 designated fan 1 with a fan 2 and a rotary drive 3 for the fan 2 , The rotary actuator is a brushless external rotor DC motor 3 educated. The motor 3 has a stator arrangement according to the invention 5 and a rotor rotatably mounted therein 6 on.

The rotor 6 has a bell-shaped rotor body 7 made of metal, on which the fan wheel 2 is attached. On the inner circumference of the rotor body 7 is an annular permanent magnet 8th ( 2 ) arranged as a drive magnet, wherein the rotor body 7 also serves as magnetic inference. The rotor body 7 is on a wave 9 attached in the stator assembly 5 is rotatably mounted.

The stator arrangement according to the invention 5 has a stator core 10 made of soft magnetic metal, which is stacked for example from individual sheets. The stator core 10 has six stator poles regularly distributed around the outer circumference 11 ( 3 ). Each stator pole 11 has a radially outwardly projecting pole web 12 and an adjoining pole tooth 13 , The pole teeth 13 lie the rotor magnet 8th opposite and have an asymmetric curvature to reduce the cogging torque. On every pole 12 is a stator winding 14 arranged.

On the stator core 10 is a two-piece slot insulation 15 arranged, consisting of a first 16 and a second one 17 Nutisolationsteil. The two parts 16 . 17 are each axially on both sides of the stator core 10 plugged or postponed. The slot insulation parts 16 . 17 are essentially congruent with the poles 11 of the stator core 10 so that the pole webs 12 all around and the pole teeth 13 isolated from above and below. The two slot insulation parts 16 . 17 each extend to about the axial center of the stator core 10 and touch each other. The two slot insulation parts 16 . 17 be through the stator windings 14 on the stator core 10 fixed. In addition, the two parts 16 . 17 be connected to each other, for example, by a positive locking connection.

The second slot insulating part 17 also has a sleeve-shaped bearing receptacle 18 on, on the inner circumference of the stator core 10 is applied. The camp recording 18 extends over the entire axial length of the stator 4 and towers over the stator core at both ends 10 and the slot insulation 15 , At the two axial ends of the bearing receiver 18 are each camp 19 for rotary mounting of the rotor shaft 8th arranged. Camps 19 are in the example each in a paragraph 20 the camp admission 18 used and can be, for example, rolling or plain bearings. Depending on the application, however, only one or more than two bearings can be advantageous.

The advantage of the two-part slot insulation 15 with integrated bearing support 18 is a simple assembly and simplified manufacture of the stator 4 , In the prior art, the slot insulation is usually produced in one piece by injection molding. For this purpose, the stator core must be inserted into an injection mold and molded around. To prevent the liquid plastic from cooling uncontrollably and too quickly when hitting the stator core, the stator core must first be warmed up to the process temperature, which can take a long time, depending on the mass of the stator core. Furthermore, care must be taken that all parts cool down at approximately the same speed so that no tension cracks form. This makes the process slower overall and difficult to control.

In the two-part groove insulation according to the invention 15 can both parts 16 . 17 be made independently in separate spraying processes. There is no stator core 10 is overmolded, can be dispensed with a complex insert-injection mold. In addition, the cycle time can be chosen much shorter because no massive stator core 10 must first be heated to process temperature. As a result, no temperature gradients occur during cooling, which prevents stress cracks. Overall, the manufacturing process of the slot insulation 15 faster, easier and better controllable. The production costs are also significantly lower due to the lower reject rate.

In addition, the installation of the slot insulation 15 and the windings 14 on the stator core 10 Machine done and is therefore also cost feasible.

In 1 is still seeing that underneath the stator core 10 a separate housing 21 for receiving a printed circuit board 22 with the slot insulation 15 connected is. The housing 21 essentially has a housing body 23 made of plastic, which is preferably produced in an injection molding process. The housing body 23 has a mounting hole 24 with which the case 21 on the bearing receiver 18 the slot insulation 15 can be placed. The camp recording 18 has a notch or a rejuvenation to it and for centering 40 , The lower part of the bearing receiver 18 protrudes into the housing 21 into it. The circuit board 22 therefore has a recess in this area 25 , so that the camp recording 18 not on the circuit board 22 rests.

On the top of the case body 23 is opposite to the drive magnet 8th an annular flange 26 arranged, which together with this a narrow gap 27 forms, which is to prevent the entry of dirt into the Statorraum or complicate.

At the bottom of the case body 23 is a large housing opening 28 arranged through which the circuit board 22 in the case 21 can be used. The housing opening 28 is through a cover plate 29 dust and liquid tightly closed. The cover plate 29 is preferably made of plastic, but may also be made of another material, such as metal. For sealing the housing 21 is the cover plate 29 for example, with the housing body 23 fully welded, glued, screwed or connected by a clip connection with this firmly. The compound can be made detachable or non-releasable. To power the PCB 22 is a cable gland in the housing body 23 provided by a rubber grommet 30 is sealed. In addition, the cables can 41 in the rubber grommet 30 potted or sealed by other sealants. Alternatively, the cable gland instead of a rubber grommet 30 also be sealed elsewhere. Thus, the contacts can be performed, for example, according to the same principle of the housing, as the connecting means are guided through the slot insulation.

The electrical connection between the stator windings 14 and the circuit board 22 via contact pins 31 which protrude through the housing body into the housing. As in 3 and 4 The stator is visible 4 in the example, two such pins 31 , The housing body has at its the stator 4 Assigned housing wall 32 at least one contact opening 33 on, through which the one or more contact pins 31 succeed.

The contact pins 31 are according to the invention in the second Nutisolationsteil 17 embedded. The pins can 31 be sprayed with in particular during injection molding. Because the mass of the contact pins 31 relatively small compared to the slot insulation part 17 is, here are not the problems that would occur when overmolding a stator core. By injection molding is the connection between the contact pin 31 and slot insulation part 17 absolutely dust and waterproof. Alternatively, the contact pin can also be introduced by a plug-in assembly in the slot insulation. The contact pins 31 are substantially U-shaped with two legs, the leg 34 in the case 21 protrudes much longer than the other leg 35 , Both thighs 34 . 35 each have an electrical contact surface, which consists of the Nutisolationsteil 17 protrudes. As in particular in 6 is seen, the winding wire 36 a stator winding 14 with the short thigh 35 connected. In the example, the winding wire 36 several times wrapped around the leg-end and soldered with this. The stator arrangement 5 can be preassembled ready for use before it is connected to the housing. Around the long thigh 34 forms the slot insulation part 17 a cylindrical collar 37 that also goes into the case 21 protrudes ( 6 ). Inside the case 21 is the contact pin 31 directly with the circuit board 22 soldered. Alternatively, between contact pin 31 and circuit board 22 For example, be arranged a plug or screw. In addition, the collar can 37 also have other shapes, the mold preferably in the form of the contact opening 33 is adapted and, for example, can also be square or oval.

The second slot insulating part 17 also points to each stator pole 11 a cylindrical support foot 38 on ( 3 ), on the case body 23 on or rests and supports the stator. The long thighs 34 the contact pins 31 are each arranged coaxially in one of these support legs, wherein the collar 37 has a smaller diameter than the support leg 38 , Alternatively, the support feet may also have other shapes, but with the collar 37 the support foot 38 should not completely cover, so that the supporting function is maintained.

For easier positioning of the slot insulation 15 can the housing body 23 to the support feet 38 complementary depressions 39 in which the support feet 38 when placing the housing 21 on the slot insulation 15 intervention.

So through the contact openings 33 no dust and no liquid in the housing 21 can penetrate, are the housing body 23 and the second groove insulating part 17 inventively welded together. For this purpose, preferably an ultrasonic welding method is used. Here are the support legs 38 , paragraph 20 the camp admission 18 and the collar 37 the contact pins 31 with the housing body 23 tightly connected. Ideally, the housing body 23 from the same plastic as the second slot insulation part 17 so that a homogeneous and absolutely tight weld connection is created, through which the contact 33 and the attachment opening 24 be reliably sealed. In addition, the support feet increase the stability of the stator assembly 5 ,

The assembly of the stator assembly according to the invention 5 takes place in the following steps. First, the two Nutisolationsteile 16 . 17 injection-molded, with the contact pins 31 in the second part 17 to be overmoulded. The two slot insulation parts 16 . 17 be axially on the stator core 10 deferred and the pole web 11 with the stator windings 14 wound. The stator windings 14 fix the slot insulation 15 , consisting of the two slot insulation parts 16 . 17 on the stator core 10 , Subsequently, the winding wires 36 electrically with the contact pins 31 connected. On the thus finished stator 4 becomes the case body 23 put on, with the contact pins 31 through corresponding contact openings 33 and the camp admission 18 through a mounting hole 24 in the case 21 protrude into it.

For sealing the housing 21 against dust and liquid is the housing body 23 with the slot insulation 15 welded. In the case 21 can through a housing opening 28 a circuit board 22 be used, the circuit board 22 Holes for the contact pins 31 having. The contact pins 31 are then connected to the circuit board 22 soldered or plugged and the housing opening 28 by means of a cover plate 29 locked. For sealing the cover plate 29 this is also welded, so that the housing 21 is completely protected against dust and liquids.

LIST OF REFERENCE NUMBERS

1

Fan

2

fan

3

rotary drive

4

stator

5

stator

6

rotor

7

rotor body

8th

ring magnet

9

wave

10

stator core

11

stator

12

Polsteg

13

pole tooth

14

stator

15

slot insulation

16

first groove insulation part

17

second slot insulation part

18

bearing seat

19

camp

20

Paragraph warehouse admission

21

casing

22

circuit board

23

housing body

24

attachment opening

25

recess

26

annular flange

27

gap

28

housing opening

29

cover

30

rubber grommet

31

pin

32

upper housing wall

33

contact opening

34

long thigh

35

short thigh

36

winding wire

37

collar

38

Support foot

39

deepening

40

Rejuvenation camp admission

41

electric wire

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 20302576 U1 [0004]

Claims (18)

Stator arrangement, in particular for a brushless DC motor ( 3 ), with a stator core ( 10 ), on which several stator windings ( 14 ) are arranged, with a slot insulation ( 15 ) on the stator core ( 10 ) is arranged, with a printed circuit board ( 22 ) in one with the stator core ( 10 ), separate housing ( 21 ), wherein at least one stator winding ( 14 ) via a connecting means ( 31 ) with the printed circuit board ( 22 ) is electrically connected and the connecting means ( 31 ) through a passage opening ( 33 ) in the housing ( 21 ), characterized in that the connecting means ( 31 ) in the slot insulation ( 15 ) is embedded by the groove insulation ( 15 ) a collar ( 37 ) around the connecting means ( 31 ) and that the collar ( 37 ) the passage opening ( 33 ) dust and liquid tight. Stator arrangement according to claim 1, characterized in that the collar ( 37 ) with the housing ( 21 ) connected is. Stator arrangement according to claim 1 or 2, characterized in that the collar ( 37 ) within the passage opening ( 33 ) with the housing ( 21 ) is welded, pressed or glued. Stator arrangement according to one of claims 1 to 3, characterized in that the collar ( 37 ) with the housing ( 21 ) is ultrasonically welded. Stator arrangement according to one of claims 1 to 4, characterized in that the slot insulation ( 15 ) consists of plastic. Stator arrangement according to one of claims 1 to 5, characterized in that the slot insulation ( 15 ) is injection-molded from plastic and the connecting means ( 31 ) is encapsulated in it. Stator arrangement according to one of claims 1 to 6, characterized in that the connecting means ( 31 ) is designed as a contact pin. Stator arrangement according to claim 7, characterized in that the contact pin ( 31 ) substantially U-shaped with two legs ( 34 . 35 ) is formed and that the first leg ( 35 ) for contacting the stator winding ( 14 ) and the second leg ( 34 ) for contacting the printed circuit board ( 22 ) is trained. Stator arrangement according to claim 8, characterized in that the two limbs ( 34 . 35 ) are different in length. Stator arrangement according to claim 9, characterized in that the groove insulation collar ( 37 ) on the longer leg ( 34 ) is arranged. Stator arrangement according to one of claims 1 to 10, characterized in that the slot insulation ( 15 ) is formed in two parts and both groove insulation parts ( 16 . 17 ) axially on the stator core ( 10 ) are pushed. Stator arrangement according to claim 11, characterized in that the two slot insulation parts ( 16 . 17 ) are positively connected to each other. Stator arrangement according to claim 11 or 12, characterized in that a slot insulating part ( 17 ) a bearing receiver ( 18 ) having. Stator arrangement according to one of claims 1 to 13, characterized in that the housing ( 21 ) a housing body ( 23 ), that the housing body ( 23 ) a housing opening ( 28 ) for inserting the printed circuit board ( 22 ) and the housing opening ( 28 ) by a cover plate ( 29 ) is dust-tight and liquid-tight sealable or closed. Stator arrangement according to claim 14, characterized in that the housing body ( 23 ) an attachment opening ( 24 ) for mounting the housing ( 21 ) on the slot insulation ( 18 ) and is connected thereto. Stator arrangement according to claim 14 or 15, characterized in that the housing body ( 23 ) consists of plastic. Stator arrangement according to one of claims 14 to 16, characterized in that the cover plate ( 29 ) consists at least partially of plastic. Stator arrangement according to one of claims 14 to 17, characterized in that the cover plate ( 29 ) with the housing body ( 23 ) is glued or welded or secured by a clip connection.

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