US20120189456A1

US20120189456A1 - Guide geometry for half-axial fan wheels

Info

Publication number: US20120189456A1
Application number: US13/387,820
Authority: US
Inventors: Andreas Schiel; Matthias Ludwig
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2009-07-30
Filing date: 2010-06-01
Publication date: 2012-07-26
Also published as: EP2459883A1; DE102009028130A1; EP2459883B1; CN102472289A; WO2011012351A1; JP2013500426A; JP5709866B2

Abstract

A fan wheel (150) of a fan (130) comprises suction blades (210) having a leading edge (220) facing an axial inlet direction of the fan wheel, and exhaust blades (230) having an exhaust edge (240) facing a radial outlet direction of the fan wheel, as well as one deflecting element (270) connected positively or non-positively to at least one exhaust blade so as to deflect air from an active area of the suction blades (210) to an active area of the exhaust blades.

Description

The invention relates to a fan. In particular, the invention relates to a fan wheel in a fan for use in a motor vehicle.

PRIOR ART

Fans with half-axial fan wheels are often used in ventilation or air conditioning blowers, and these fan wheels can have a higher efficiency than purely axial and purely radial fan wheels. A half-axial fan wheel represents a combination of an axial fan wheel and a radial fan wheel. An axial section of the fan wheel sucks in the air to be delivered in the manner of a propeller from a direction parallel to the axis of rotation. The air already sucked in flows through a radial section of the fan wheel in the radial direction in the manner of a centrifuge.
In order to divert air which has passed through the axial section of a half-axial fan wheel to the radial section, a deflecting element is mounted in the region between the two sections. The deflecting element is usually secured on a fan motor and can have a conical shape, for example. The radially extending exhaust blades of the axial part of the half-axial fan wheel are not in contact with the fixed deflecting element so as to minimize frictional losses and noise generation. Owing to the resulting gap between the ends of the exhaust blades and the deflecting element, a certain portion of the air sucked in escapes instead of leaving the fan wheel in the radial direction exclusively between the exhaust blades. The efficiency of such a half-axial fan wheel therefore remains below a possible maximum.

DISCLOSURE OF THE INVENTION

It is therefore the underlying object of the invention to indicate a fan wheel which overcomes this disadvantage and is furthermore easy to manufacture.
The object is achieved by a fan having a fan wheel as claimed in claim 1 and by a motor vehicle as claimed in claim 10. Subclaims indicate advantageous or possible additional features.
According to a first aspect, a fan wheel of a fan comprises suction blades having a leading edge facing an axial inlet direction of the fan wheel, and exhaust blades having an exhaust edge facing a radial outlet direction of the fan wheel, and a deflecting element for deflecting air from an active area of the suction blades to an active area of the exhaust blades, wherein the deflecting element is connected positively and/or nonpositively to at least one exhaust blade.
In contrast to known half-axial fan wheels, the deflecting element follows the rotary motion of the fan wheel relative to a fan motor. The connection between the deflecting element and at least one exhaust blade makes it possible to eliminate a gap between the exhaust blade and the deflecting element and thus ensure that the desired direction and speed is imposed on the exhausted air as it flows out. In particular, some or all of the exhaust blades can be connected to the deflecting element, forcing all the exhausted air to pass between exhaust blades.
At least one of the suction blades can be formed in one piece with an exhaust blade. In one embodiment, a combined suction and exhaust blade can have a suction section and an exhaust section. One of the boundary surfaces of the combined combined suction and exhaust blade can rest partially or over its full length against the deflecting element. It is also possible for the number of exhaust blades to be greater or smaller than the number of suction blades. In addition to combined suction and exhaust blades, it is possible, for example, for further discrete exhaust blades to be formed in the fan wheel. In one embodiment, the fan wheel comprises twice as many exhaust blades as combined air blades. In a corresponding way, it is also possible for the number of suction blades to exceed the number of exhaust blades.
The deflecting element can be connected to the exhaust blade by means of a coupling fit. This is advantageous especially where fan wheels are manufactured in large numbers, the intention being to create a positive or nonpositive connection between the deflecting element and the exhaust blades by means of a simple work step. The coupling fit can have pegs and apertures corresponding to the latter, for example. As an alternative, the deflecting element can have a peripheral edge into which a plurality of exhaust blades engage, for example. Other types of positive or nonpositive connection between the deflecting element and the exhaust blades are also possible, e.g. latching in, adhesive bonding, riveting, screwing, welding, soldering, keying or caulking.
The suction blades and the exhaust blades can form a one-piece element of the fan wheel. Such a one-piece element can additionally have a hub and/or reinforcing elements that follow a periphery or a peripheral contour of the fan wheel. In one embodiment, the reinforcing element comprises a hollow-cylindrical section which delimits the suction blades toward the outside in the radial direction.
The one-piece element can be without an undercut with respect to a joint surface radially symmetric with the axis of rotation. For example, the one-piece element can be manufactured in a casting or injection molding process in a permanent mold or die that can be parted along the joint surface, allowing the one-piece element to be removed from the permanent mold or die. The joint surface can be one section of a plane perpendicular to the axis of rotation. The choice of a joint surface radially symmetric with the axis of rotation advantageously enables the one-piece element to be designed in such a way that neither the suction blades nor the exhaust blades present a hindrance during removal from the permanent mold or die. Any structures used to reinforce the fan wheel, e.g. the hub or the reinforcing surface, are also shaped in such a way that they do not hinder removal from the mold or die. As a result, large numbers of fan wheels can be produced using a permanent mold or die which comprises just two parts and no slides.
The fan can furthermore comprise a fan motor having a shaft which supports the fan wheel, wherein a drive torque is transmitted from the fan motor to the fan wheel by means of the deflecting element. The fan wheel can be injection-molded onto the shaft or a shaft socket on the hub, for example. The shaft can be connected to a stator or a rotor of the fan motor, and the shaft can be rotatably supported on one side or on two sides. In particular, the shaft can be set up to transmit shear, bending, tension and/or thrust forces between the fan wheel and the stator or rotor of the fan motor without participating in transmission of the drive torque from the fan motor to the fan wheel. Introducing the drive torque into the fan wheel by means of the deflecting element means that it is not necessary to transmit the drive torque to the exhaust blades by means of the suction blades, thus enabling the suction blades to be shaped in a manner optimized for advantageous flow without being affected by strength requirements.
The fan motor can comprise an external rotor connected nonpositively to the deflecting element. By virtue of the design of the external rotor, the drive torque can be introduced into the deflecting element at a relatively large radial distance from the axis of rotation, where the lever forces are low, thereby keeping structural stresses on the deflecting element to a low level. In addition, a fan motor stator surrounded by the external rotor can occupy a space on the side of the deflecting element facing away from the fan wheel in an optimum manner, thus enabling the fan to be constructed in a particularly compact way.
The external rotor can comprise one or more permanent magnets. The relatively large mass of the permanent magnet at a relatively great distance from the axis of rotation of the fan wheel means that the rotational inertia of the fan wheel is high, with the result that the rotation of the fan wheel as it is driven by the fan motor is damped and, as a result, is more uniform. It is thus possible to minimize noise generation during the driving of the fan wheel by means of alternately activated windings of the stator.
According to a second aspect, a motor vehicle comprises a fan with the fan wheel described above.

BRIEF DESCRIPTION OF THE FIGURES

The invention is described in greater detail below with reference to the attached drawings, in which:

FIG. 1 shows a schematic illustration of a fan system in a motor vehicle;

FIG. 2 shows a sectioned side view through a fan having a fan wheel for use in the fan system shown in FIG. 1, and

FIG. 3 shows an isometric view of part of the fan wheel from FIG. 2.

FIG. 1 shows a schematic illustration of a motor vehicle fan system 100. A motor vehicle 110 comprises an intake section 120, a fan 130 and a distributing section 140. The fan 130 comprises a fan wheel 150 and a fan motor 160. Not included in the illustration in FIG. 1 are optional elements of the motor vehicle fan system 100, such as filters, flaps, valves, heat exchangers, condensers and other elements which are not of further relevance here. The fan motor 160 sets the fan wheel 150 in rotation, with the result that air is sucked in from outside the motor vehicle 110, through the intake section 120, into the fan wheel 150 and is then delivered to the interior of the motor vehicle 140 through the distributing section 140.
The intake section 120 and the distributing section 140 are often embodied in such a way as to be integrated into a common section. The fan 130 can be capable of insertion in the manner of a cartridge into the intake section 120, the distributing section 140 or the common section. In the vicinity of the fan 130, the section can have an element which converts a radial flow direction of air flowing out of the fan wheel 150 into a linear flow direction, e.g. a pressure increasing spiral, which furthermore compresses the exhausted air.
FIG. 2 shows the fan 130 from FIG. 1 in a sectioned side view. The fan 130 comprises the fan wheel 150 and the fan motor 160, which are connected to one another by means of a shaft 300.
The fan wheel 150 comprises suction blades 210 having leading edges 220 and exhaust blades 230 having exhaust edges 240. The suction blades 210 extend radially outward from a hub 250 of the fan wheel to a reinforcing surface 260 of the fan wheel 150, said surface following part of the peripheral contour of the fan wheel 150. The suction blades 210 are shaped in such a way that air is sucked in from below in the axial direction when the fan wheel 150 rotates. The suction blades 210 merge into exhaust blades 230, which are arranged along the reinforcing surface 260 in the direction of rotation. When the fan wheel 150 is set in rotation, the exhaust blades 230 impart an acceleration in the circumferential direction to air which has passed through the suction blades 210 in the axial direction, with the result that the accelerated air is exhausted in the radial direction at the exhaust edges 240 by virtue of a centrifugal effect. In the region of the exhaust edges 240, the exhaust blades 230 can be bent in a crescent shape for improved outflow.
At the top, the suction/ exhaust blades 210, 230 of integrated design border on a deflecting element 270. The deflecting element 270 is of annular design in the region of the hub 250 and is connected by means of a coupling fit to the blades 210, 230 or to the hub 250. In addition, the two exhaust blades 230 that are visible in this view have slotted holes 290 in the region of their exhaust edges 240, into which corresponding pegs 280 of the deflecting device 270 are fitted, thereby establishing a nonpositive connection between the deflecting element 270 and the exhaust blades 280.
The fan motor 160 comprises a stator 310 and an external rotor 320 with a permanent magnet 330. The external rotor 320 is formed in one piece with the deflecting element 270 and accommodates the permanent magnet 330. The permanent magnet 330 can be fitted, pressed and/or adhesively bonded into the external rotor 320. A torque between the stator 310 and the permanent magnet 330 is introduced directly, by means of the external rotor 320, to the deflecting element 270 and, from there, into the exhaust blades 230, thus driving the fan wheel 150 around the stator 160. The stator 310 can be connected in a torsionally rigid manner to a surrounding structure in order to secure the fan 130 in the intake section 120 and/or in the distributing section 140, for example.
The shaft 300 is connected to the hub 250 and to the deflecting element 270 for conjoint rotation therewith. This connection can be established by welding, adhesive bonding, pressing, latching or by means of a coupling fit, for example; the hub 250 can also be injection-molded or molded onto the shaft 300. At its upper end, the shaft 300 is supported rotatably on the stator 310 of the fan motor 160. The shaft 300 ensures that the fan motor 160 is fixed in the axial direction relative to the fan wheel 150. In addition, the shaft 300 transmits tilting, bending and shear forces between the fan wheel 150 and the stator 310 of the fan motor 160. However, the rotatable support in the stator 310 means that the shaft 300 does not transmit any torque and, in particular, any drive torque from the fan motor 160 to the fan wheel 150.
FIG. 3 shows a one-piece element 340 as part of the fan wheel 150 from FIG. 2. The element 340 comprises the hub 250, the reinforcing surface 260 and a number of exhaust blades 230 and a number of suction blades 210, although only a section of the latter is visible in the illustration selected. The suction blades 210 merge into some of the exhaust blades 230; the integrated suction/exhaust blades 210/230 extend between the hub 250 and the reinforcing surface 260. Formed between each pair of exhaust blades 230 integrated with suction blades 210 is a further exhaust blade 230, which does not extend as far as the hub 250 in the radial direction. The exhaust blades 230 which are designed so as to be integrated with suction blades 210 have slotted holes 290 to receive pegs 280 formed on the deflecting element 270 from FIG. 2 in order to produce a coupling fit between the deflecting element 270 and the exhaust blades 230.
The one-piece element 340 is constructed in such a way that it can be produced easily in a casting or injection molding process and can then be removed without problems from the mold or injection molding die. A permanent mold or die for the production of the integrated molding 240 can comprise an upper and a lower section, wherein a joint surface between the sections can extend in a radial plane of the element 340 or can follow the upper contour of the blades 210/230, at least in sections.
To produce the fan wheel 150, the deflecting element 270 from FIG. 2 can be connected to the one-piece element 340 in a simple operation. By means of the coupling fit in the region of the pegs 280 and slotted holes 290 or in the region of the hub 250, the deflecting element 270 can be connected quickly and permanently to the one-piece element 340.

Claims

1. A fan (130) having a fan wheel (150), which has

suction blades (210) having a leading edge (220) facing an axial inlet direction of the fan wheel (150), and exhaust blades (230) having an exhaust edge (240) facing a radial outlet direction of the fan wheel (150),

and a deflecting element (270) for deflecting air from an active area of the suction blades (210) to an active area of the exhaust blades (230), characterized in that

the deflecting element (270) is connected to at least one exhaust blade (230).

2. The fan (130) as claimed in claim 1, characterized in that at least one suction blade (210) is formed in one piece with an exhaust blade (230).

3. The fan (130) as claimed in claim 1, characterized in that the deflecting element (270) is connected to the exhaust blade (230) by means of a coupling fit (280, 290).

4. The fan (130) as claimed in claim 3, characterized in that the coupling fit (280, 290) has pegs (280) and apertures (290) corresponding to the pegs.

5. The fan (130) as claimed in claim 1, characterized in that the suction blades (210) and the exhaust blades (230) form a one-piece element (340) of the fan wheel (150).

6. The fan (130) as claimed in claim 5, characterized in that the one-piece element (340) is without an undercut with respect to a joint surface radially symmetric with the axis of rotation.

7. The fan (130) as claimed in claim 1, characterized in that the fan comprises a fan motor (160) having a shaft (300) which supports the fan wheel (150), wherein a drive torque is transmitted from the fan motor (160) to the fan wheel (150) by means of the deflecting element (270).

8. The fan (130) as claimed in claim 7, characterized in that the fan motor comprises an external rotor (320) connected nonpositively to the deflecting element (270).

9. The fan (130) as claimed in claim 8, characterized in that the external rotor (320) comprises at least one permanent magnet (330).

10. A motor vehicle (110) comprising a fan (130) as claimed in claim 1.

11. The fan (130) as claimed in claim 1, characterized in that the deflecting element (270) is connected nonpositively to at least one exhaust blade (230).

12. The fan (130) as claimed in claim 11, characterized in that the deflecting element (270) is connected to the exhaust blade (230) by means of a coupling fit (280, 290).

13. The fan (130) as claimed in claim 12, characterized in that the coupling fit (280, 290) has pegs (280) and apertures (290) corresponding to the pegs.

14. The fan (130) as claimed in claim 11, characterized in that the deflecting element (270) is also connected positively to at least one exhaust blade (230).

15. The fan (130) as claimed in claim 1, characterized in that the deflecting element (270) is connected positively to at least one exhaust blade (230).