EP1851441A1

EP1851441A1 - Mini fan

Info

Publication number: EP1851441A1
Application number: EP05816289A
Authority: EP
Inventors: Rodica Peia
Original assignee: Ebm Papst St Georgen GmbH and Co KG
Current assignee: Ebm Papst St Georgen GmbH and Co KG
Priority date: 2005-02-24
Filing date: 2005-12-10
Publication date: 2007-11-07
Also published as: US20070134109A1; JP4977039B2; JP2008532463A; WO2006089578A1

Abstract

The invention relates to a mini fan comprising a fan wheel (64) provided with fan wings (80) and an electric motor (61) for driving said fan wheels. The drive motor (61) is provided with a permanent-magnet external rotor (62) and an internal stator (90) which is embodied in the form of a claw-pole stator provided with pole sheets (88, 110) whose claw poles (84, 86) are interlinked with each other. A coil body (57) is placed between the pole sheets and is provided with a central section connecting two opposite side parts (50, 56), one of which is embodied in the form of a support for electric elements (96, 98) of the motor (61).

Description

Mini fan

The invention relates to a mini fan. Such fans are also referred to as small or micro fan.

For air measurement, e.g. For air conditioning in motor vehicles, sensor fans are used. These have e.g. an outer diameter of 30 mm, i. it is according to the technical usage of mini fans.

Such mini fans are also used to cool processors in computers, to cool devices in small devices, etc., and their dimensions are very small. For example, to have

• the fans of the ebm-papst series 250 dimensions of 8 x 25 x 25 mm,

• the ebm-papst 400F series dimensions of 10 x 40 x 40 mm,

• the ebm-papst 400 series of 20 x 40 x 40 mm,

• and the fans of the ebm-papst 600 series of 25 x 60 x 60 mm.

The power consumption of such fans is 0.4 ... 0.6 W for the 250 series, 0.7 to 0.9 W for the 400F series and 0.9 ... 3 for the 400 and 600 series , 4 W. The weight is eg 5 g in the 250 series, 17 to 27 g in the 400 / 400F series, and 85 g in the 600 series.

For fans of this miniature size, which must be very inexpensive, it is important to make their assembly extremely easy, so that in their production a high degree of automation is possible and you get a uniform quality and low noise of such fans.

In such extremely small fans is added to aggravating that their components, quite comparable to those of a mechanical movement, are very delicate and therefore not very robust. The rotor shaft, for example, often has only the thickness of a knitting needle and can therefore be easily bent when handled carelessly, causing the fan to become unusable. The same applies to pole sheets.

It is therefore an object of the invention to provide a new mini-fan.

According to the invention, this object is solved by the subject matter of claim 1. By virtue of the fact that a part of the bobbin is designed as a carrier on which electrical elements of the motor can be arranged, e.g. Components, connection elements or the like, gives a very simple and compact design, as it is especially for mini fans of utmost importance. Also, there is the advantage of a low-vibration construction and consequently a low-noise operation in such a mini-fan.

Further details and advantageous developments of the invention will become apparent from the described below and shown in the drawing, in no way as a limitation of the invention to be understood embodiment, and from the other dependent claims. It shows:

Fig. 1 is a partially sectioned illustration of a space

Mini fans according to a preferred embodiment of the invention, in a very greatly enlarged representation,

2 is a three-dimensional view of the fan of FIG. 1, in which this is not shown cut,

3 shows an illustration of a contact pin with which the miniature fan can be plugged onto a circuit board, this contact pin producing both an electrical and an additional mechanical connection of the fan to the circuit board,

4 is a section taken along the line IV - IV of FIG. 3,

5 is an exploded view of the essential parts of a mini fan according to the invention, 6 is a perspective view of a pole piece,

7 is a section taken along the line VII-VII of FIG. 6,

8 shows a section through a claw-pole stator which uses pole plates according to FIG. 6, FIG.

9 is a three-dimensional view from above on the in Fig. 8 in section shown inner stator,

10 is a three-dimensional plan view from below of the inner stator of FIG. 9,

1 1 is a schematic representation of a loading method, which can be preferably used within the scope of the invention,

12 is a perspective view of a first variant,

Fig. 13 is a top plan view of the fan of Fig. 12, and

Fig. 14 is a three-dimensional view of a second variant.

Fig. 1 shows a mini-fan 10, which in practice usually can have a diameter of 30 to 35 mm, but for reasons of clarity extremely greatly enlarged. It has an outer housing 12 made of an insulating plastic, and this housing has at the top an air inlet opening 14 and laterally air outlet openings 16, of which in Fig. 1, only the rear is visible.

Starting from the air inlet opening 14, the housing 12 widens via an annular portion 18 to a cylindrical portion 20th

On the annular portion 18 is a circuit board 22, and on this a sealing ring 24 is attached from sponge rubber in the manner shown. The circuit board 22 is substantially round and has in its center a transverse web 26, of which in Fig. 1, only the rear half is visible and on which an NTC resistor 28 is arranged, which serves as a temperature sensor for air, which in the direction of Arrows 30, 32 flows from above through the opening 14 and flows through the lateral opening 16.

The NTC resistor 28 (in SMD construction) is connected by tracks 34 with contact pins 36, 38, which are arranged in the cylindrical part 20 of the outer housing 12 in the illustrated manner isolated. These metal pins 36, 38 have below each a Kontaktierungsfuß 36 'and 38', each of which has two resilient elements 40, 42, which are shown in Fig. 4. The Kontaktierungsfüße 36 'and 38' are plugged according to Fig. 3 and Fig. 4 in an opening 44 of a printed circuit board 46. This opening 44 is connected to a metal layer 47, which extends through the opening 44 and is connected to a conductor track 48 of the printed circuit board 46. The Kontaktierungsfüße 36 ', 38' so make electrical connections from the circuit board 46 to the fan 10 and its temperature sensor 28 ago. Especially with very small fans, it is common that the components for the electronic commutation are not in the fan 10 itself, but on the associated circuit board 46. However, it is within the scope of the invention also possible to arrange these components in the fan 10 itself.

The cylindrical part 20 of the outer housing 12 is closed at the bottom by a carrier 50, in the middle of a metal bushing 52 is arranged. This is surrounded by a cylindrical portion 54 which is integral with the circuit board 50 and which merges at its upper end in an annular disc 56, which forms a bobbin for a stator winding 58 together with the parts 50 and 54. The board 50 has notches 51 at its outer edge, through which the contact pins 36 and 38 and other contact pins 53 protrude.

Within the sleeve 52 is a (not shown) sintered bearing for the shaft 60 of the outer rotor 62 of a motor 61st The rotor 62 has a support member 64 made of plastic, which has in its center a hub 66, in which the upper end of the Shaft 60 is injected, which has a knurling 68 for better anchoring. The outer rotor 62 has approximately the shape of an upside-down shell and has at its periphery a rim portion 70 which extends approximately parallel to the shaft 60.

As shown, in this edge portion 70, a permanent magnet 72 is injected directly in the two-component injection molding process. The magnet 72 consists of hard ferrites in a matrix of plastic, and therefore this plastic can be represented with its hard ferrite particles 74, which naturally can only be represented schematically, e.g. be injected as a ring in the support member 64, wherein the interfaces, which is symbolized by dotted lines 76, intimately connect by melting the plastics.

Subsequent to the injection of the magnet ring 72, it is radially magnetized in a suitable device, as shown symbolically in FIG. 1 by the letters N (north pole) and S (south pole) in the usual way.

Integral with the support member 64 are radially extending fan blades 80, i. it is preferably a radial fan.

Of great advantage in the invention is that in this type of production of the outer rotor 62 is already largely balanced after the injection of plastics, so that at most even smaller balancing work will be necessary. Also, there is a saving in assembly, since just such extremely small parts are difficult to handle and assemble, and therefore could easily occur during assembly errors. The invention avoids rejects, since the rotor 62 is present with its rotor magnet during assembly as a finished and tested part that only needs to be mounted in the camp, which usually happens by inserting the shaft 60 in the camp.

In the fan of FIG. 1, the free end 82 of the shaft 60 forms a thrust bearing with the local portion 83 of the carrier 50, which is opposite to this end 82. Thereby, the end 82 of the shaft 60 is pressed down against the portion 83, and this is done by the magnetic ring 72 relative to those in FIG. 1 shown cylindrical portions 84, 86 of a Klauenpolteils 88 is offset in the axial direction. In this way, the magnetic ring 72 is pulled by an axial force F down.

The portion 83 is formed by the material of the carrier 50 passes through openings 85 of the bushing 52 in its interior during manufacture, cf. Fig. 10.

As Figs. 5 to 10 show particularly clearly, the fan 10 has an inner stator 90, which is designed as Klauenpolkonstruktion.

The bobbin 57 already described is wound with a coil 58, which usually has two separate windings, which are wound bifilar, z. B. a drive winding with two terminals 92, 94 and a sensor winding with two terminals 96, 98, see. Fig. 5 and Fig. 9. The use of a sensor coil and a drive coil is known in this context, cf. EP 1 104 950 A2 (EP226 = EP-3046). If a Hall sensor is used, z. As well as an operation with two drive coils according to WO 00/35074 possible (PCT221 = PCT-3044).

The terminals 92 to 98 are, as shown, led to lateral contacts embedded in the board 50, preferably in the MID method, and each connected to associated contact pins 53 extending through the slots 51 and thereby electrically connected to produce there provided metallic coatings 100.

At the bottom of the carrier 50 two barbs 102, 104 are formed, see. 5 and 10. (In Fig. 1, these barbs are not shown.) With these barbs, the mini fan is releasably latched to the circuit board 46 (Fig. 3), wherein the contact pins 36 ', 38', 53, the electrical connection produce to the tracks 48 of the circuit board 46. After its winding with the coil 58, the upper pole plate 88 is applied to the bobbin 57 from above. This has a central recess 106, with which it is pressed onto the bushing 52. According to FIGS. 6 to 8, the upper pole plate 88, and likewise the bottom pole plate 1 10 identical to it, has on its outer side 12 a plastic coating which a) the outside of the claw poles 84, 86 covered, see. Fig. 9 and b) extends approximately in the form of circular ring segments 1 14, 1 16 in gaps between the adjacent claw poles 84, 86, cf. Fig. 6.

Each of these annular segments 1 14, 1 16 is provided with a projection 1 18 or 120 (FIG. 7), which serves to weld this circular ring segment to the adjacent side part 50 or 56 of the bobbin 57. This is preferably done by laser welding, wherein the projection in question forms a permanent connection with the associated side wall 50 or 56 of the bobbin 57, as shown in Fig. 8 for the side wall (support) 50.

The lower pole plate 1 10 is pressed in the same manner with its central opening on the sleeve 52 and then welded to the carrier 50.

As FIG. 9 and FIG. 10 show particularly well, the carrier 50 for this purpose has two recesses 122, 124, through which the claw poles of the pole plate 110 are pushed through. According to FIGS. 9 and 10, the two pole sheets 88 and 110 are mechanically offset by 90 ° relative to one another and consequently interdigitate one another. Each of the claw poles has five radially extending recesses 126, which are shown in Fig. 6, and the plastic 1 12 is anchored in these recesses 126 and fills them. This reduces magnetostrictive noise and turbulence in the air. The recesses 126 serve primarily to reduce eddy current losses.

Fig. 1 1 shows a preferred method for equipping the carrier (board) 50 in such mini-fans. The fact is exploited that this carrier 50 can be brought into any desired shape during injection molding.

In FIG. 1A), adhesive 130 is dispensed onto the carrier 50 at certain points, which, as shown, can have any shape.

In Fig. 1 1 B) 130 corresponding SMD components 132 are applied to these adhesive dots. In Fig. 1 1 C) is allowed to cure the adhesive dots 130 in a corresponding oven.

In Fig. 1 1 D), the component is coated with conductive traces 134, and

in Fig. 1 1 E) these tracks 134 are cured by means of UV light. So then the carrier 50 is equipped and ready for use.

This production is also referred to as "molded interconnected device."

By this manufacturing process, the necessary connections for the electronics are applied directly to the bobbin 57. The injection molded parts produced in this way are prepared immediately for further processing. Holes or adjustments no longer have to be incorporated later, but are integrated directly into the components by the molds of injection molding. Beyond the low cost of manufacturing, and the quality benefits, this process also offers positive environmental benefits by eliminating leaded solder and eliminating PCBs from commonly non-recyclable materials, and increases reliability at a low cost.

Fig. 12 and Fig. 13 show a variant in which no special circuit board is required. Instead, two printed conductors 140, 142 are introduced into the upper side 144 of the fan housing 146 in the hot embossing process. The trace 140 is connected at its left end to a contact pin 148, and at its right end to an NTC resistor 28 ", and the trace 142 is connected at its right end to a contact pin 150 and at its left end to the NTC Resistance 28 '.

It should be noted that in FIGS. 12 and 13 parts which have the same function as in the preceding figures are also designated by the same reference numerals and will not be described again. Around the air inlet opening 14 ', a projecting collar 152 is provided in FIGS. 12 and 13, which protects the NTC resistor 28' against mechanical damage. A ridge 152, on which the NTC resistor 28 "and the printed conductors 140, 142 are located, is formed as part of the housing 146.

The contact pins 148, 150 extend through the housing 146 and protrude down therefrom.

Fig. 13 shows the fan of Fig. 12 in plan view from above. By eliminating a special circuit board for the NTC resistor 28 'results in a significant simplification and cheapening, the full functionality is maintained.

Fig. 14 shows a variant. In this case, a flexible permanent magnet 226 or 228 is arranged in each case in a cylindrical portion 220 of the lower housing part 212 at two mutually opposite points 222, 224. These magnets take the form of flexible plastic parts containing hard ferrite particles and are also referred to as "rubber magnets".

Prior to the production of the housing part 212, these magnets are placed in an injection mold and held there at the locations which are designated in Fig. 14 with 228. The magnet in question can be bent in this process in a desired shape, if this proves to be useful in the production.

Subsequently, the magnets are encapsulated with the plastic of the lower housing part, so that they are firmly anchored in this housing part and can not fall out.

These magnets 226, 228 serve to rotate the rotor 62 to a position before starting, from which it can easily start.

The invention thus provides a mini fan with a very compact and robust Innenstator 90. The reader must take into account that if z. B. the outer diameter of the miniature fan 10 in Fig. 2 has a value of 35 mm, the diameter denoted by D in Fig. 8 is only about 20 mm, that is, it is extremely small parts which are a) at low cost and b ) must be made with great precision.

Furthermore, it should be noted that some claw poles for magnetic reasons may still have much more complicated shapes than the shape shown in Fig. 6, which can make manufacturing and processing even more difficult.

Naturally, many modifications and modifications are possible within the scope of the present invention.

Claims

claims

1. Mini fan, which has a fan blades (80) provided with fan (64) and an electric drive motor (61) for driving this fan, which drive motor (61) has a permanent magnetic outer rotor (62) and an inner stator (90), which latter as a stator with sheet metal parts (88, 1 10) is formed, and the fan blades (80) on the fan wheel (64) are provided.

2. Mini fan according to claim 1, wherein the stator as an inner stator with Polblechen (88, 1 10) is formed, the claw poles (84, 86) engage with each other, wherein between the Polblechen a bobbin (57) is arranged, which has a central portion (54), with which two opposite side parts (50, 56) are connected, one of which is designed as a carrier for electrical elements (96, 98) of the motor (61), wherein the carrier (50) in particular with openings ( 122, 124) for the implementation of the claw poles of the pole plate adjacent to it (1 10) is provided.

3. Mini fan according to claim 2, wherein at least the support (50) adjacent pole piece (1 10) at least partially with a plastic part (1 14, 1 16) is provided, which is fixedly connected to the carrier (50).

4. miniature fan according to claim 3, wherein the plastic part (1 14, 1 16) in the region between two adjacent claw poles (84, 86).

5. miniature fan according to claim 3 or 4, wherein the plastic part (1 14, 1 16) on its the carrier (50) adjacent side with a projection, in particular a rib (120) is provided, which projection with the carrier (50 ) is welded.

6. Mini fan according to one of claims 3 to 5, wherein the plastic part (1 14, 1 16) at least partially via a claw pole (84, 86) extends.

7. mini fan according to claim 6, wherein a claw pole (84, 86) with recesses (126) is provided, in which the plastic of the plastic part (1 14, 1 16) is anchored.

8. miniature fan according to one of claims 2 to 7, wherein within the bobbin (57) a tube (52) made of soft ferromagnetic material is arranged.

9. mini fan according to claim 8, wherein the tube (52) as a magnetic yoke for the pole face (88, 1 10) is formed.

10. Mini fan according to claim 8 or 9, wherein the tube (52) is provided in the region of the carrier with at least one recess which extends over part of the tube circumference and through which the plastic of the bobbin (57) into the interior of the tube (52) extends.

1 1. Mini fan according to claim 10, wherein the plastic, which extends into the interior of the tube (52) is formed as part of a thrust bearing for the storage of the permanent magnetic outer rotor (62).

12. Mini fan according to one of the preceding claims, wherein in the region of the air inlet opening (14) a sealing ring (24) made of sponge rubber is provided.

13. miniature fan according to claim 12, wherein the sealing ring (24) on a printed circuit board (22) is arranged, which is provided in the region of the air inlet opening (14).

14. Miniature fan according to claim 13, wherein on the circuit board (22) a temperature sensor (28) is arranged.

15. mini fan according to claim 14, wherein the circuit board (22) has a web (26). which extends in the region of the air inlet opening (14) and serves as a carrier for the temperature sensor (28).

16. Miniature fan according to one of the preceding claims, wherein a temperature sensor (28) is provided, and in which the temperature sensor (28) leading conductor tracks (140, 142) are applied to the fan housing (144) in the hot stamping process.

17. Miniature fan according to one of the preceding claims, wherein the fan blades (80) extend substantially parallel to the axis of rotation (82) of the mini fan.

18. Miniature fan according to one of the preceding claims, which has a substantially cylindrical outer housing (20, 220) with an axial air inlet opening (14) and at least one lateral air outlet opening (16).

19. Miniature fan according to one of the preceding claims, which is provided with mounting feet (53, 36 ", 38 ¹ ) which at least partially also serve for the electrical connection of the fan.

20. Miniature fan according to one of the preceding claims, wherein on the bobbin (57) a two-stranded stator winding (58) is provided which is wound bifilar.

21. Miniature fan according to one of the preceding claims, wherein in a region in the vicinity of the rotor (62), a housing part (212) is provided, in which at least one permanent magnet (226, 228) is fixed by plastic injection molding.

22. Miniature fan according to claim 21, wherein the permanent magnet as a plastic-bonded flexible magnet (226, 228) is formed.