EP1703140B1 - Cooling device for a electrically driven centrifugal fan - Google Patents

Description

The invention relates to an electric motor-driven radial fan according to the preamble of claim 1.

From the DE 102 04 037 A1 a generic radial fan is known, which has a fan housing with a rotating therein impeller and each with a suction and exhaust port. The impeller is connected via a drive shaft to the electric motor. The electric motor is covered by a pot-shaped cap, within the cap a printed circuit board is arranged with electronic components. The electric motor drives a fan wheel for cooling the electric motor and the electronic components arranged on the printed circuit board.

The FR 2764747A discloses a fan in which an impeller is driven by a motor, wherein the air flow generated by the impeller via externally mounted on the housing blade-shaped air inlets into the interior of the housing along a plate and the electrical components attached thereto, such as

Transistors, for cooling is passed.

From the FR 2827345A A blower is also known, in which an air flow generated by an impeller located outside the housing is directed into the interior of the housing, the air flow being guided along a plate on which various electrical components to be cooled are arranged.

The volume flow conveyed by means of the known radial fan is adjusted via the rotational speed of the electric motor. This is the purpose of the electronic components, which are arranged on the circuit board within the cap.

In the meantime, a multitude of electronic components for the control of the electric motor in an integrated circuit (IC), also referred to as a chip, is being merged. The problem here is that the heat generation due to the power loss in the ICs used is relatively high. For cooling the ICs, it is known to use metal heat sinks. Without such forced cooling, the IC would heat up to unacceptably high temperatures in a very short time and be switched off by means of a protective circuit, whereby the fan would also be put out of operation. So that the heat absorbed by the heat sink can be released back to the environment, the heat sinks are often mounted on the outside of the housing. The size of the heat sink used for the application has a negative effect on the overall height of the radial fan.

The invention has for its object to provide a radial fan of the generic type, which is characterized by low susceptibility and low height of the radial fan at low production costs.

This object is achieved with the subject matter of claim 1. According to the invention, an integrated circuit (IC or chip) for controlling the motor is conductively connected to the printed circuit board and that the air flow generated by the cooling wheel is directed to the IC. The radial fan is due to the design of the invention without additional heat sink for the IC, which has a positive effect on the height.

The basic idea of the invention is to selectively guide an air flow generated by means of the fan wheel and thus to ensure effective cooling of highly-stressed electronic components, in particular of the IC. In this case, not only the partial air streams blown directly from the fan wheel but also the intake air streams are understood by the air flows generated by the fan wheel. For carrying one or more (partial) air flows, as will be explained, separate air flow directing means are provided with which the air stream or streams are conducted directly onto the IC or past it. It is additional Alternatively, it is also possible to modify the existing architecture of the radial fan by making minor changes with regard to optimum component cooling. In particular, at this point the possibility of introducing a flow opening in the anyway existing printed circuit board mentioned by a (partial) air flow is directed directly towards IC.

A per se known and space-saving relative arrangement of the circuit board, preferably the cup-shaped cap and the electric motor to each other should be maintained in an embodiment of the invention. It is provided that the circuit board has a lid of the cap facing top and an opposite bottom and that the circuit board is arranged substantially parallel to the cover of the cap and orthogonal to the drive shaft of the electric motor and that the fan between the electric motor and the lid of the Cover is arranged. Advantageously, the fan is designed as a radial fan. By this design cool outside air can be sucked in axially and radially, in particular parallel to the circuit board, flowed out.

As already mentioned at the beginning, it is surprisingly possible already by smaller modifications of the architecture to contribute to the improvement of the cooling. Advantageously, for example, provided in the circuit board, a flow-through and the IC are arranged adjacent to this flow-through. A (partial) air flow then flows through the flow opening directly to the IC.

The cooling effect can be further improved by arranging the IC within the (partial) air flow flowing through the flow-through opening. For this purpose, the IC can be arranged, for example, at a distance from the printed circuit board on a support which protrudes from the printed circuit board at an angle, in particular between 90 ° and 10 °. It can be provided to make the support flexible, so as to be able to vary the position of the IC relative to the flow-through.

According to an advantageous embodiment of the invention, the IC on the underside of the circuit board, spaced from this, arranged. Additionally or alternatively, the electronics are arranged on the underside of the printed circuit board. Due to this inventive measure, a (partial) airflow flowing from the fan impeller can flow along the upper side of the circuit board without heating, and then, for example through the flow opening in the circuit board, directly to the IC on or flow past it. As a result, a particularly effective cooling of the IC is ensured.

In order to achieve the highest possible cooling capacity, it is expedient if at least one inflow opening for outside air is provided in the cover cap, which is preferably arranged relative to the fan wheel such that an immediate flowing along of the outside air at the electronics and / or on the IC and / or on the electric motor and associated preheating of this air is avoided before reaching the fan wheel.

This is achieved according to a first embodiment, characterized in that the inflow opening is arranged in the cover of the cap, in particular immediately adjacent to the fan. The suction opening of the fan wheel is directed in the direction of inflow, so that mainly or better exclusively, cool outside air is sucked.

A second embodiment provides that the inflow opening is introduced into the peripheral wall of the cap, preferably adjacent to the IC. As a result, the cool outside air can flow along the IC even before reaching the fan wheel.

According to an alternative embodiment, the inflow opening is formed by a gap between the cap and the blower housing. This variant has manufacturing advantages, since no additional opening must be made in the cap.

According to the invention, to optimize the cooling of the IC, it is further provided that the electronics and / or the electric motor are arranged such that the outside air flowing in through the inflow opening does not flow directly past these components before reaching the IC. This is achieved in particular by the provision of air baffles.

A particularly advantageous arrangement is achieved in that a recess for the fan wheel is provided in the printed circuit board and that the fan wheel is arranged through the printed circuit board, so that an outgoing (partial) air flow along the top and another outgoing (partial) air flow along the bottom of the circuit board sweeps. If no electronics are now arranged on the upper side of the printed circuit board, the air flowing above the printed circuit board, without being heated, can be led directly to the IC. The horizontal air flow below the printed circuit board, the electronics arranged on the underside of the printed circuit board is cooled in parallel.

The cooling of the IC and / or the electronics is improved in that at least one Luftstromleiteinrichtung is provided. To reduce installation costs, this can be formed on the cover of the cap and integrally therewith. For example, the cool air flow can be diverted from the upper side of the printed circuit board through the flow-through opening to the IC by means of the airflow line device. On the underside of the circuit board, a louver can be attached, which prevents the flow of (part) air flowing along the electronics to flow to the IC. As guide vanes, for example, guide plates, integrally formed on webs webs or channels can be used.

According to an advantageous embodiment of the invention, an inflow opening for the fan wheel is provided in the circuit board. The fan is in this case immediately adjacent to this inflow opening, arranged on the underside of the circuit board. The generated air flow is discharged exclusively from the fan wheel on the underside of the printed circuit board. By this measure, the height can be reduced, as can be dispensed with louvers between the circuit board and the lid of the cap. Furthermore, the used, shortened impeller has a positive effect on the minimization of the overall height.

To increase the speed and thus the cooling capacity of the ventilation wheel, a transmission can be connected between the electric motor and the fan.

Fig. 1

eine schematische Schnittdarstellung einer ersten Ausführungsform eines erfindungsgemäßen Radialgebläses,

Fig. 1a

eine schematische Ansicht entsprechend derjenigen in Fig. 1 eines weiteren Ausführungsbeispiels, und

Fig. 1 b

eine schematische Ansicht einer Abdeckkappe des Gebläses nach Fig.1a von unten.

Fig. 2

eine schematische Ansicht einer Abdeckkappe des Gebläses nach Fig.1 von unten,

Fig. 3

eine schematische Schnittdarstellung einer zweiten Ausführungsform eines erfindungsgemäßen Radialgebläses,

Fig. 4

eine schematische Ansicht einer Abdeckkappe des Gebläses nach Fig.3 von unten.

In the following the invention will be explained in more detail with reference to the exemplary embodiments illustrated in the figures. In the figures show:

Fig. 1

a schematic sectional view of a first embodiment of a radial fan according to the invention,

Fig. 1a

a schematic view corresponding to those in Fig. 1 a further embodiment, and

Fig. 1 b

a schematic view of a cap of the fan after 1a from underneath.

Fig. 2

a schematic view of a cap of the fan after Fig.1 from underneath,

Fig. 3

a schematic sectional view of a second embodiment of a radial fan according to the invention,

Fig. 4

a schematic view of a cap of the fan after Figure 3 from underneath.

In the figures, the same components or components with the same function with identical reference numerals.

Fig. 1 shows a schematic sectional view of a radial blower according to the invention 1, which has a flat-cylindrical blower housing 2 with a rotating therein impeller 3 and an impeller 3 driving electric motor 4. The blower housing 2 has a central suction opening 5 and a lateral outlet opening 6. Such radial blower 1 are used to promote a gas-air mixture for a gas boiler, for a gas burner or the like.

The electric motor 4 is mounted on the suction opening 5 opposite side 7 of the blower housing 2. It has a continuous drive shaft 8 which projects into the blower housing 2 and which is non-rotatably connected at its one end region 9 to the blower wheel 3 and at the opposite end region 10 with a fan wheel 11 designed as a radial fan. About the common drive shaft 8, the electric motor 4 drives both the impeller 3, and the fan 11 at.

A flat circuit board 12 is arranged orthogonal to the drive shaft 8. On the circuit board 12 is the electronics, not shown, which extends exclusively on the underside 13 of the circuit board 12.

The electric motor 4 with the circuit board 12 and the fan 11 are enclosed by a cup-shaped cover 14. The cup-shaped cover 14 is frontally bounded by a circular cover 15, from which extends a cylindrical peripheral wall 16 perpendicular to the blower housing 2, so that the aforementioned components are protected against contact. The cap 14 is fixed by means of a screw or locking connection, not shown, to the fan housing 3, so that circuit board 12, electric motor 4 and fan 11 are enclosed on all sides.

The circuit board 12 extends parallel to the cover 15 of the cap 14, so that between the lid 15 and circuit board 12, a space is formed.

On the underside 13 of the printed circuit board 12, a carrier 17 is mounted with an integrated circuit (IC) 18 arranged thereon. The power loss of the IC is about 3 W to 4 W with a thermal resistance of about 60 K / W. The carrier 17 is in the plane of the drawing at an angle of about 80 ° from the circuit board 12 downwards, so that the IC 18 is spaced from the circuit board 12.

By means of the carrier 17 of the IC 18 is placed directly below a flow opening 19, ie directly in a from a top 20 of the circuit board through the flow opening 19 flowing (partial) air flow.

In the circuit board 12, a recess 32 is provided for the fan 11. The fan wheel 11 passes through the recess 32 in the printed circuit board 12, so that the horizontal air flow discharged from the fan 11 is divided into two (partial) air streams 27 and 28, wherein the (partial) air flow 27 along the top 20 and the ( Part) air flow 28 along the bottom 13 of the circuit board 12 flows. Alternatively, the air flow 28 may be omitted, so that accordingly the opening may be smaller.

In the drawing plane, an inlet opening 21 for outside air is provided immediately above the fan wheel 11 in the lid 15 of the cover cap 14. The cool outside air is sucked axially from the fan 11 and flowed radially in the direction of arrow.

To direct a (partial) air flow in the direction of IC 18, an air flow guide 22 is provided. The Luftstromleiteinrichtung 22 consists in the present embodiment of suitably designed and integrally formed with the lid 15 of the cap 14 and down vertically projecting baffles 23, 24, 25. The schematically illustrated webs 23, 24, 25 together with the lid 15 and the circuit board 12 a closed on four sides of the cooling channel 26. The (partial) air flow 27 flows horizontally in this channel 26 and can flow down in the direction of flow opening 19.

In Fig. 2 the cup-shaped cap 14 is shown with lid 15 in a schematic view from below. In the center of the lid 15, the inflow opening 21 is formed. Laterally of the inflow opening 21, the Luftströmleiteinrichtung 22 extends with cooling channel 26 with the walls 23, 24, 25. It is conceivable that the webs or walls 23, 24, 25 directly to the in Fig. 1 illustrated flow opening 19 are brought in the circuit board 12 in order to achieve a bundled as possible flow of the IC 18.

In the Fig. 1b and Figure 1c is one of an alternative embodiment. In this, the channel 26 may be formed as a radial fan housing, at the output of the flow opening 19 connects. The circuit board 20, together with the circumferentially closed wall 24, the side walls of the spiral housing, whereby the air flow of the radial fan can be effectively directed to the opening 19.

In the following, the (partial) air flows within the cap 14 will be described.

The fan 11 draws in during operation axially outside air through the inflow opening 21 in the lid 15 of the cap 14. Characterized in that the inflow opening 21 is disposed immediately adjacent to the fan 11, the outside air flows directly into the fan 11, without flowing on the electronics, the IC 18 and the electric motor 4 along. As a result, heating of the intake air is avoided.

Since the fan 11 passes through the printed circuit board 12 axially, two partial air streams 27 and 28 are generated. The (partial) air flow 27 flows along the upper side 20 of the printed circuit board 12 and is at least partially deflected by the louver 22 by 90 ° in the direction of the underlying in the drawing plane flow opening 19 and thus passes directly to the plane below the printed circuit board 12th arranged on the top 20 of the circuit board 12 no electronics, the partial air flow 27 has barely heated upon reaching the IC 18 and therefore provides for effective cooling of the ICs. The (partial) air flow 28 flows along the underside 13 of the circuit board 20, thus cooling the mounted on the circuit board 12 electronics.

Fig. 3 shows a schematic sectional view of another embodiment of a radial blower according to the invention 1. The basic structure of the in Fig. 3 shown radial blower corresponds to the above-described construction of the first embodiment. In order to avoid repetition, the following will mainly deal with the differences between the two exemplary embodiments. There are further embodiments conceivable that can correspond to (partial) combinations of both embodiments.

The inlet opening 21 for outside air is in the in the 3 and 4 illustrated embodiment of a radial fan 1 in the peripheral wall 16, immediately adjacent to the blower housing 3, respectively. In a further, only indicated embodiment, the inflow opening 21 is introduced immediately adjacent to the IC 18 in the peripheral wall 16.

In the exemplary embodiment illustrated, the support 17 holding the IC is arranged at a right angle to the printed circuit board 12 so that the air flowing through the likewise provided throughflow opening 19 passes by the IC. Also in the second embodiment, the electronics is arranged exclusively on the underside 13 of the printed circuit board 12.

In the circuit board 12, a flow opening 29 is provided for the fan 11. The fan wheel 11 is placed directly in the plane below the Anströmöffnung 29 and passes through the circuit board 12, unlike the first embodiment, not. The fan 11 blows the sucked through the inflow opening 29 from the top 20 of the circuit board 12 air exclusively below the circuit board 12.

In Fig. 4 the cup-shaped cap 14 is shown in a schematic view from below. In the peripheral wall 16, the inflow opening 21 can be seen for outside air.

In the following, the (partial) air flows in the second embodiment within the cap 14 will be described.

The fan wheel 11 arranged below the printed circuit board 12 sucks in air from the upper side of the printed circuit board 12 through the opening 29. It should be additionally mentioned that the fan 11, the circuit board 12 of course, in the second embodiment can prevail - but it should be ensured that the fan 11 emits the sucked air exclusively on the bottom 13 of the circuit board 12.

As a result of the negative pressure resulting from the suction of air on the upper side 20 of the printed circuit board 12, air flows from below through the throughflow opening 19 in the printed circuit board 12 into the space between the cover 15 and the printed circuit board 12. Much of this (part) designated by the reference numeral 30 Air flow passes through the inflow opening 21 into the interior of the cover cap 14. The still cool outside air strips on its way in the direction of flow opening 19 past the IC 18 and cools it.

The (partial) air stream 31 which has flowed out from the fan wheel 11 flows along the underside 13 of the printed circuit board 12 and thus cools the electronics arranged there.

It is understood that baffles may be provided, which optionally prevent mixing of the air streams 30 and 31.

In the figures, a further variant of the radial fan is not shown, in which the inflow opening is formed by a circumferential gap between the cap 14 and blower housing 3. Also not shown is a possible integration of one or more transmissions in the drive train between the electric motor 4 and fan 11.

LIST OF REFERENCE NUMBERS

1

centrifugal blower

2

fan housing

3

blower

4

electric motor

5

suction

6

outlet

7

front

8th

drive shaft

9

End portion of the drive shaft

10

End portion of the drive shaft

11

fan

12

circuit board

13

Bottom of the circuit board

14

cap

15

cover

16

peripheral wall

17

carrier

18

Integrated circuit (IC)

19

flow-through

20

Top of the circuit board

21

inflow

22

Luftstromleiteinrichtung

23

web

24

web

25

web

26

deflection

27

(Partial) air flow

28

(Partial) air flow

29

inflow opening

30

(Partial) air flow

31

(Partial) air flow

32

recess

Claims (16)

1. A radial fan (1) with an electric motor (4) and a fan impeller (3) driven by the electric motor (4), with a printed circuit board (12) with electronics, an air impeller (11) which is disposed on a side of the electric motor (4) being opposed to the fan impeller (3), and which is driven by the electric motor for cooling the electronics and with a cap (14) protecting the electric motor, said cap having a cover (15) and a peripheral wall (16), wherein an integrated circuit (IC) (18) is disposed on the printed circuit board (12), characterized in that a guiding device (22) is provided for directing an air flow (27, 30) produced by the air impeller (11) to the integrated circuit (IC) (18).
2. The radial fan according to Claim 1, characterised in that at least one inflow opening (21) is provided on the cap (14) for external air.
3. The radial fan according to Claim 2, characterised in that the inflow opening (21) is disposed in the cover (15) of the cap (14).
4. The radial fan according to Claim 2, characterised in that the inflow opening (21) is in the peripheral wall (16) of the cap (14).
5. The radial fan, in particular with a fan housing (2), according to Claim 2, characterised in that the inflow opening (21) is in the form of a gap between the cap (14) and the fan housing (2).
6. The radial fan according to at least one of Claims 1 to 5, characterised in that the guiding device (22) is integrally formed with the cap (14).
7. The radial fan according to any of the preceding claims, characterised in that the integrated circuit (IC) (18) is attached to a support (17) which is positioned on a different level to the level of the printed circuit board (12) in the air flow (27, 30).
8. The radial fan according to any of the preceding claims, characterised in that the printed circuit board (12) is disposed substantially parallel to the cover (15).
9. The radial fan according to any of the preceding claims, characterised in that a flow through opening (19) for the air flow (27, 30) is provided in the printed circuit board (12), the integrated circuit (IC) (18) being disposed adjacent to the flow through opening (19).
10. The radial fan according to any of Claims 7 to 9, characterised in that the support (17) projects at an angle, in particular of between 90° and 10°, from the printed circuit board (12),
11. The radial fan according to any of the preceding claims, characterised in that the integrated circuit (IC) (18) is disposed on the lower side (13) of the printed circuit board (12).
12. The radial fan according to at least one of the preceding claims, characterised in that the air impeller (11) is a radial fan.
13. The radial fan according to Claim 12, characterised in that the printed circuit board is disposed in relation to the outflow openings of the radial impeller such that part of the cooling air is blown out over the printed circuit board, and part below the printed circuit board.
14. The radial fan according to Claim 13, characterised in that the arrangement of the printed circuit board divides the air flow (27, 30) into substantially equal parts.
15. The radial fan according to any of the preceding claims, characterised in that a recess (32) for the air impeller (11) is provided in the printed circuit board (12).
16. The radial fan according to Claim 1 or 4, characterised in that an inflow opening (29) for the air impeller (11) is formed on the printed circuit board (12), the air impeller intaking above the printed circuit board, and blowing out below the printed circuit board.

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