AXIAL FLOW FAN

The invention relates to an axial flow fan (1) comprising a fan wheel (2) which has a plurality of primary fan blades (3) which are arranged between an inner fan wheel hub (4) and an outer collar (5); and comprising a fan drive (6), which is arranged in the inner hub (4) and which cooperates with a drive electronics arrangement (7) arranged in a stationary outer hub (4), characterized in that a radial flow fan (8) is integrated in the inner hub (4) for generating a cooling air flow for the fan drive (6) and/or the drive electronics arrangement (7).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of German Patent Application No. 102017210629.8 filed Jun. 23, 2017, the disclosure of which is herein incorporated by reference in its entirety.

DESCRIPTION

The invention relates to an axial flow fan according to the preamble of Claim1.

In a fan of this type, a fan drive is provided which cooperates with a drive electronics arrangement that responds to the respective operating conditions and controls the fan drive so that the desired fan output is achievable.

Since the drive electronics arrangement is arranged within the hub of the axial flow fan, temperature states may occur which in an extreme case may damage the electronics arrangement.

It is therefore the object of the present invention to create an axial flow fan of the type indicated in the preamble of Claim1, which enables an improved cooling within the hub, particularly of the drive electronics arrangement.

The solution to this problem is carried out by the features of Claim1.

Correspondingly, in the case of an axial flow fan, comprising a fan wheel and a fan drive, which cooperates with a drive electronics arrangement, a radial flow fan is provided, integrated in the hub, which makes it possible to generate a targeted cooling air flow for the fan drive and/or for the drive electronics arrangement, which extends in a targeted way within the hub or the housing of the axial flow fan and thus achieves an improved cooling in a targeted and efficient way, in particular of the drive electronics arrangement and/or the fan drive.

A ventilator is known from DE 44 41 649 B4 which is provided with slot-like recesses in its hub that represent air passage openings and are to act as a radial fan wheel, wherein these slot-like recesses exclusively form outlet openings to guide a cooling air flow from an electric motor out of the hub to the outside over the shortest path. Therefore, these slot-like recesses do not represent a radial flow fan which would be suitable for generating a cooling air flow.

The subclaims contain as subject matter advantageous refinements of the invention.

The radial flow fan preferably has radial fan blades, which may be arranged and fixed on the hub to generate the cooling air flow.

It is additionally provided that a defined flow path is achievable for the cooling air flow due to the radial flow fan and preferably due to the geometry of the hub or of the housing of the axial flow fan.

It is herein particularly preferred if this flow path may be directed across cooling ribs for the drive electronics arrangement.

Furthermore, the advantage arises that the radial flow fan may form a stiffening arrangement for the entire area of the fan wheel hub of the axial flow fan.

The fan drive is preferably designed as an electric motor, which has a stator which is surrounded on the outer side by a rotor.

It is hereby particularly preferred that the stator is designed such that it forms a housing for the radial flow fan.

In another particularly preferred embodiment, the housing formed by the stator forms a heat sink for the drive electronics arrangement. The stator is encapsulated by a plastic coating for this purpose in a particularly preferred embodiment.

The design of an axial flow fan1according to the invention arises from an overview ofFIGS. 1 through 3and comprises a fan wheel2, which has a plurality of primary fan blades3, of which one fan wheel is designated with reference numeral3inFIGS. 1 through 3respectively.

As is clear fromFIGS. 1 through 3, primary fan blades3are arranged between an inner hub4and a collar5which radially surrounds primary fan blades3on their outer periphery, wherein primary fan blades3are connected both to hub4and also to collar5.

Axial flow fan1, depicted inFIGS. 1 through 3, has a fan drive6, which is designed as an electric motor6in the particularly preferred embodiment provided here. Fan drive6is hereby integrated in hub4and cooperates with a drive electronics arrangement7, likewise integrated in hub4, which is clear from the depiction inFIGS. 2 and 3.

As explained at the outset, axial flow fan1according to the invention has a radial flow fan8, which generates a cooling air flow for cooling the drive electronics arrangement and/or fan drive6and is integrated in hub4. Radial flow fan8has a plurality of radial fan blades which are fixed on a base plate11of hub4and radial fan blades8A-8D are visible inFIG. 1. The number of radial fan blades of radial flow fan8may be adjusted to the respective application, wherein the radial fan blades of radial flow fan8are naturally arranged about the entire circumference of hub4.

It is particularly clear fromFIG. 2that fan drive6, designed as an electric motor, is provided with a stator6A, which is surrounded on the outer side by a rotor6B.

An arrangement of cooling ribs9is provided between drive electronics arrangement7and fan drive6according to the depiction fromFIG. 2.

As is primarily indicated inFIG. 2, it is also possible to form a defined flow path within hubs4and10for the cooling air flow, which is depicted inFIG. 2by arrows P1-P10, wherein arrows P1and P2illustrate the inlet flow area and arrow P10illustrates the outlet flow area, whereas arrows P3-P9illustrate the flow path within an outer hub10and inner hub4, which is preferably designed such that an optimized cooling is possible for drive electronics arrangement7and, in the particularly preferred embodiment shown, also for fan drive6. AsFIG. 2additionally shows, the cooling air flow extends in the particularly preferred embodiment across cooling rib arrangement9, which is symbolized by arrow P5.

InFIG. 3, axial flow fan1according to the invention is reproduced again in an enlarged view.FIG. 3illustrates that outer stationary hub10is connected to a stationary frame14surrounding collar5on the outer peripheral side via connecting struts, of which an arrangement of three is designated with reference numeral15.

FIG. 3additionally illustrates that inner hub4is designed as pot shaped and has a base plate11, which is surrounded on the outer peripheral side by an outer hub ring12. An inner hub ring13is provided on the inner periphery.FIG. 3additionally illustrates that the radial fan blades of radial flow fan8are designed as curved and extend, corresponding to their curvature, from inner hub ring13up to outer hub ring12, wherein the curvature of the radial fan blades is adaptable to the respective application.FIG. 3additionally shows that the radial fan blades are arranged on base plate11of inner rotatable hub4.

Finally,FIG. 3illustrates that the arrangement of rotor6B, which is connected to inner hub4, has the result that, during a rotation of rotor6B, the inner hub also rotates with this, and correspondingly both primary fan blades3of fan wheel2and also the radial fan blades of radial flow fan8rotate with this, and by this means generate cooling air flow P1through P10, as illustrated inFIG. 2, and also primary flow HS (illustrated by three arrows).

InFIG. 2, arrows P2and P3symbolize an inlet flow path in outer hub10and arrow P4symbolizes a transition path in hub10to inner hub4. Subsequent arrows P5, P6, P7, P8, and P9symbolize the through flow path across cooling rib arrangement9and through hub4up to flow outlet P10.

In addition to the preceding written disclosure of the invention, reference is hereby explicitly made to the graphic representation of the invention inFIGS. 1 through 3as a supplemental disclosure of the invention.

REFERENCE SIGN LIST