WO2011154097A1

WO2011154097A1 - Sensor fan with integration of the air-guiding housing into the magnetic return path region of the motor stator

Info

Publication number: WO2011154097A1
Application number: PCT/EP2011/002581
Authority: WO
Inventors: Björn WINTER; Hansjoerg Berroth; Stefan Antes-Flores
Original assignee: Ebm-Papst St. Georgen Gmbh & Co. Kg
Priority date: 2010-06-10
Filing date: 2011-05-25
Publication date: 2011-12-15
Also published as: DE112011101937A5; DE202011100798U1

Abstract

A sensor fan (18) has a brushless drive motor (40, 50, 52, 54, 56, 58, 60, 66, 68) having a stator (50, 52, 54, 56, 58, 60, 66, 68) and having a permanent-magnetic rotor (40); a fan impeller (20) which is drive-connected to said rotor (40); an air inlet (78) through which the air flows into the sensor fan (18) during operation and on which can be mounted at least one sensor element (80) for detecting at least one characteristic of the air transported through the sensor fan (18); an air-guiding member (74) which is provided in the region of the air inlet (78) and by means of which, during operation, the air passing from the air inlet (78) is conducted to the fan impeller (20) and which, at least in a magnetically active return path region (72) of the drive motor, is formed from a ferromagnetic material and serves there as a magnetic return path for the stator; stator pole shoes (50, 52, 54, 58, 60) which are separated from the rotor (40) in each case by a magnetically active air gap (50B, 52B, 64B, 56B, 58B, 60B); stator pole cores (66) which extend in each case from a stator pole shoe (50, 52, 54, 56, 58, 60) to the magnetically active return path region (72) of the air-guiding member (74); stator windings (68) which are arranged on the stator pole cores (66) and which are separated from one another in the circumferential direction by radial passages (81), through which passages (81) the air conveyed by the fan impeller (20) can flow during operation.

Description

SENSOR FAN WITH INTEGRATION OF THE AIR LEADING HOUSING INTO THE MAGNETIC RESORT AREA OF THE ENGINE STATION

The invention relates to a sensor fan with a sensor for detecting a property of a gas flowing through the sensor fan during operation, in particular air.

Such sensor fans are very small and have about the dimensions of a

oversized thimble. They serve z. As for detecting the air temperature, humidity, the radioactivity of the air or other gases, and they have a fan, and an electric motor for driving this fan.

Being mass-produced, it is important that such fans can be made inexpensively while still ensuring accurate acquisition of the variables to be measured.

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

According to the invention, this object is achieved by the subject matter of claim 1. The fact that here the magnetic yoke for the stator of the electric motor is simultaneously formed as an air guide member for the fan, results in a compact design, wherein the sensor can be arranged so that no undesirable thermal influence of the sensor by the electric motor occurs and thus one receives very accurate measurement, the z. B. in an air conditioner allows a very constant temperature control even under extreme environmental conditions as z. B. on the one hand in the Sahara desert, on the other hand in winter in Siberia or Lapland can occur.

Further details and advantageous developments of the invention will become apparent from the following described and illustrated in the drawings, in no way as a limitation of the invention to be understood embodiments, and from the dependent claims. It shows: Fig. 1 is a longitudinal section, taken along the line II of Fig. 2; it shows the base plate 34 of a sensor fan, on which a radial fan 20 is rotatably mounted; on the underside of the fan 20, a rotor magnet 40 is fixed in the 2K process,

Fig. 2 is a plan view of the base plate 34, viewed in the direction of arrow II of FIG.

1, in a comparison with FIG. 1 even more enlarged scale,

Fig. 3 is a longitudinal section similar to FIG. 1, in which also the stator with the

Stator windings and an air guide member and a sensor are shown,

4 is a three-dimensional view analogous to FIG. 3,

Fig. 5 is a schematic representation of the annular rotor magnet with a

Magnetization in the form of a Halbach array, in which on the outer circumference of a strong magnetic field and on the inner circumference only a very weak

Magnetic field is present,

Fig. 6 is an exemplary illustration of the circuit of the stator coils in the form of a

Delta connection, and

Fig. 7 is an exemplary view of another type of circuit of the stator coils, wherein two stator coils are used to start the motor and four coils together form the motor winding for driving the rotor.

Fig. 1 shows an assembly of a sensor fan 18, namely its radial impeller 20. This has fan blades 22 which are fixed to a conical air guide 24 and from this, based on Fig. 1 and 3, projecting upwards. The air guide body 24 has an extension at the top 26, in which a shaft 28 is secured by injection molding. The fan 20 sucks air in the direction of arrows 21 so in the axial direction and transports them in the direction of arrows 23 to the outside.

The fan 20 is preferably made of a polyamide with glass fiber reinforcement by

Injection molded. Its shaft 28 is mounted in a bearing 30, which is exemplary here is shown as a sliding bearing and in the projection 32 of a base plate 34 (plastic) is attached.

The air guide body 24 has an annular at its in Fig. 1 and 3 lower end

Broadening 36, on the underside 38 in the 2K process, a magnetic ring 40 is molded. This has a polyamide matrix in which hard ferromagnetic particles are located, for. B. from neodymium, and at the interface 38 merges the polyamide matrix of the

Magnet ring 40 with the polyamide of the fan 20, which is referred to as 2K method for short, because two plastics are fused along an interface 38 with each other. This creates an excellent bond between these two plastics.

As shown in FIG. 1 and FIG. 2, six recesses 46 are provided in the base plate 34 at equal intervals (here eg 60 °), and six stator pole elements 50, 52, 54, 56, 58, 60 are provided, which are also recesses have, which are designated 48 and are aligned with the recesses 46, see. Fig. 1. The stator pole elements have pole pieces (stator pole shoes) 50A, 52A,... 60A, often referred to as "hammers".

are each separated by a magnetically active air gap 50B, 52B, ... 60B from the outer periphery 61 (Figure 2) of the permanent magnet rotor magnet 40. These air gaps can either - as shown - have a constant size, z. B. 0.2 mm, or they can, for. B. to generate a reluctance, be variable. In the latter case, a pole gap 62 of the rotor magnet 40 at the position largest air gap. Fig. 2 shows schematically such a pole gap 62, which is therefore generally no mechanical gap, but only a familiar to the electrical engineer, mental construct.

As shown in FIG. 3, each of the recesses 46, 48 associated with a pole core (Statorpolkern) 66, the z. B. may have a dimension of 2 x 2 mm. On him is one

Attached stator winding, which is designated 68. Overall, so you have the

Embodiment, a stator having six pole cores 66 and six stator windings 68. The in Fig. 3 upper ends of the pole cores 66 are secured in recesses 70 of the horizontal portion 72 of an air guide member 74, z. B. by riveting, welding or gluing. At least the horizontal portion 72 serves as a magnetic inference of the illustrated brushless drive motor and is therefore made of a ferromagnetic or soft ferromagnetic material produced, for. B. by deep drawing. The part 72 may be referred to as a magnetic return region 72.

The upper end of the air guide member 74 in Fig. 3 and Fig. 4 terminates in the circuit board 75, which is e.g. is fastened by means of support posts 76 on the air guide member 74.

As shown in FIG. 3, the circuit board 75 has in its center an opening (air inlet) 78, through which the air flows in the direction of the arrows 21 during operation. In this opening 78, a sensor or sensor element 80 of any type is attached, e.g. by means of his

Lead wires 82, which are connected to the circuit board 75, or by means of a special, not shown support member which projects into the opening 78 and on which the sensor 80 is fixed. The sensor 80 serves e.g. to capture at least one

Property of transported air, e.g. the air temperature, the humidity, the radioactivity of the air or other gases.

As shown in FIGS. 1 and 3, recesses 84 are provided at the outer ends of the wings 22, the shape of which is adapted to the shape of the air guide member 74.

Fig. 4 shows the sensor fan 18 in three-dimensional representation. The magnetic flux passes e.g. from one pole of the rotor magnet 40 through a stator pole element, e.g. the element 50, further through the associated pole core 66 to the magnetic yoke 72, through this e.g. to the pole core of the stator pole 52, and through this back to the rotor magnet 40. The windings 68 generate the current load on the

Polkernen 66.

This design makes it possible to produce a very compact shape even with an internal rotor motor.

Since the outflowing air 23 flows through passages 81, in particular radial passages 81, between adjacent windings 68, as shown in FIG. 4, one avoids heating of the sensor 80 by the outflowing air 23, i. the measured value is practically not influenced by the drive motor of the fan wheel 20.

Fig. 2 shows a radial magnetization of the rotor magnet 40. In this case, one can proceed with advantage so that one in the injection molding process (molding) in the mold a ring 88 of a soft ferromagnetic material on the radial inner side of the magnet ring 40 inserts.

The magnetic ring 40 can already be pre-magnetized in the injection mold in order to achieve an alignment of the magnetic particles, which are schematically indicated in FIG. 2 at 90. This alignment is then maintained after solidification of the polyamide matrix and, if necessary, further magnetization in the cooled state is possible to obtain a desired shape of the induced voltage.

Alternatively, a Halbach magnetization can be used as shown in FIG. In this case, one does not need a return ring 88 (FIG. 2), and one obtains on the radial

Outside 61 of the magnet ring 40 a strong magnetic field, because there is the

Add magnetic field lines, while receiving a weak magnetic field on the radial inside 92 because the field lines cancel each other there.

Due to the magnetization, which is partly already in the injection mold, one obtains sections 94, in which the magnetic flux 96 extends mainly radially from outside to inside, and one obtains sections 98, in which the magnetic flux 100 extends mainly radially from inside to outside. From the sections 98, the magnetic fluxes 102, 104 extend approximately in the circumferential direction to the sections 94. The magnetic particles 90 (FIG. 2) are correspondingly mechanically aligned by the magnetization within the injection mold, so that a corresponding magnetic field 106 is formed on the outside of the magnetic ring 40 results, as indicated schematically in Fig. 5. Due to the nature of the magnetization, the shape of this magnetic field 106 can be influenced in a known manner.

Fig. 6 shows how the coils 68 are switched to obtain a delta connection for a three-phase motor. There are two opposing coils 68 connected in series. Since the coils are denoted by 68 throughout, the reference numeral 50, 52, ... 60 of the associated pole element 50, 52, ... 60 is used for their definition, and this reference number is therefore written in parentheses.

Fig. 7 shows the circuit of the coils 68 for a so-called single-phase motor. Two of the six coils, namely those with pole elements 52 and 58, are in series switched and serve as start-up windings. Of these may possibly be omitted, so that the engine has only five coils 68 in this case.

The four coils with the pole elements 56, 54, 50 and 60 are also connected in series and serve as motor coils. These are distributed symmetrically on the circumference and thereby generate symmetrical forces on the magnetic ring 40, so that there is a smooth running of the sensor fan.

The exemplary embodiments according to FIGS. 1 to 7 thus show a sensor fan 18, which has a brushless drive motor 40, 50, 52, 54, 56, 58, 60, 66, 68 with a stator 50, 52, 54, 56, 58 , 60, 66, 68 and a permanent magnet rotor 40; a fan wheel 20 in drive connection with this rotor 40; one

Air inlet 78 through which the air flows into the sensor fan 18 during operation and to which at least one sensor element 80 for detecting at least one property of the air transported by the sensor fan 18 is mountable; a provided in the air inlet 78 air guide member 74, which in operation from the

Air inlet 78 incoming air to the impeller 20 passes and which at least in a magnetically active return region 72 of the drive motor from a

ferromagnetic material is formed and there serves as a magnetic conclusion for the stator; Stator pole pieces 50, 52, 54, 58, 60 each separated from the rotor 40 by a magnetically active air gap 50B, 52B, 64B, 56B, 58B, 60B;

Statorpolkerne 66 which each extend from a Statorpolschuh 50, 52, 54, 56, 58, 60 to the magnetically active return region 72 of the air guide member 74; and stator windings 68 which are arranged on the stator pole cores 66 and separated from each other by radial passages 81 in the circumferential direction, through which passages 81 in operation the air conveyed by the fan 20 can flow.

The fan wheel 20 preferably has at least one region 24, 36 which is formed from a thermoplastic plastic, which region 24, 36 is connected in a 2K process to the rotor magnet 40, which as a part consists of a thermoplastic material with embedded ferromagnetic particles 90 is formed, wherein the ferromagnetic particles 90 are preferably at least partially made of neodymium.

Preferably, the rotor magnet 40 is magnetized in the manner of a Halbach array (FIG. 5), and the rotor magnet 40 is preferably formed as part of an inner rotor whose Outer periphery 61 forms one of the boundaries of the magnetically active air gap 50B, 52B, 54B, 56B, 58B, 60B. Preferably, the rotor magnet 40 is provided on its side 92 remote from the magnetically active air gap 50B, 52B, 54B, 56B, 58B, 60B with a magnetic yoke 88 and magnetized in the radial direction (FIG. 2).

Preferably, a base member 34 is provided of a non-metallic material, on which a bearing 30 is provided for rotatably supporting the fan wheel 20, wherein preferably the Statorpolschuhe 50, 52, 54, 56, 58, 60 are mounted on the base member 34, and preferably the pole cores 66 are fixed on the base part 34.

Preferably, the fan 20 is designed as a radial fan.

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

The stator has six stator poles in the embodiment, but it may be e.g. also have two, four or eight poles.

Claims

claims

1. Sensor fan (18), which has

A brushless drive motor (40, 50, 52, 54, 56, 58, 60, 66, 68) having a stator (50, 52, 54, 56, 58, 60, 66, 68) and a permanent magnet rotor (40);

a fan wheel (20) drivingly connected to said rotor (40);

an air inlet (78) through which the air flows into the sensor fan (18) during operation and to which at least one sensor element (80) for detecting at least one property of the air transported by the sensor fan (18) is mountable;

an air guide member (74) provided in the region of the air inlet (78) which, during operation, directs the air coming from the air inlet (78) to the fan wheel (20) and which is formed of a ferromagnetic material at least in a magnetically active return region (72) of the drive motor and there serves as a magnetic return for the stator;

Stator pole pieces (50, 52, 54, 58, 60) each separated from the rotor (40) by a magnetically active air gap (50B, 52B, 64B, 56B, 58B, 60B); Statorpolkerne (66), which in each case by a Statorpolschuh (50, 52, 54, 56, 58, 60) to the magnetically active return region (72) of the

Air guide member (74) extend; and

Stator windings (68) which are arranged on the stator pole (66) and separated by radial passages (81) in the circumferential direction, through which passages (81) in operation, the air conveyed by the fan (20) can flow.

2. Sensor fan according to claim 1, wherein the fan wheel (20) has at least one region (24, 36) which is formed from a thermoplastic plastic,

which region (24, 36) in the 2K process is connected to the rotor magnet (40), which is formed as a part of a thermoplastic with embedded ferromagnetic particles (90).

3. Sensor fan according to claim 2, wherein the ferromagnetic particles (90) consist at least partially of neodymium.

4. Sensor fan according to claim 2 or 3, wherein the rotor magnet (40) in the manner of a Halbach array (Fig. 5) is magnetized.

5. Sensor fan according to claim 2 or 3, wherein the rotor magnet (40) is formed as part of an inner rotor whose outer periphery (61) forms one of the boundaries of the magnetically active air gap (50B, 52B, 54B, 56B, 58B, 60B).

6. Sensor fan according to claim 5, wherein the rotor magnet (40) on its side facing away from the magnetically active air gap (50 B, 52 B, 54 B, 56 B, 58 B, 60 B) side (92) provided with a magnetic yoke (88) and in the radial direction is magnetized (Fig. 2).

7. Sensor fan according to one of the preceding claims, wherein a base part (34) is provided from a non-metallic material, on which a bearing (30) for rotatably supporting the fan wheel (20) is provided.

8. A sensor fan according to claim 7, wherein the Statorpolschuhe (50, 52, 54, 56, 58, 60) are mounted on the base part (34).

9. Sensor fan according to claim 7 or 8, wherein the Statorpolkerne (66) are mounted on the base part (34).

10. Sensor fan according to one of the preceding claims, wherein the fan wheel (20) is designed as a radial fan.