EP1617085B2 - Damped fan - Google Patents

Abstract

The axial fan (1) for the cooling of especially electrical and/or electronic components in a computer, has a fan housing (2) which in the axial direction has a rectangular cross section and fastening holes (3) in its four corners for fastening of the fan to a component to be cooled or to a housing containing such a component. At least one elastic damping element (9) is integrated into the fan and is installed in such a way that it is effective between the fan impeller (6) and fastening holes. A damping component may be provided in each corner of the housing, with the fastening hole provided inside the damping element. An independent claim is included for a computer, especially a PC, which incorporates the aforesaid cooling fan.

Description

The present invention relates to an axial fan according to the preamble of claim 1. Such axial fans are used for air cooling of heat generating components. Above all, they are used as computer fans for air cooling of electrical and / or electronic components in personal computers or computers. They include a fan housing with an axially durchströmbaren Luftleitrahmen in which a fan is rotatably mounted, wherein the fan housing in the axial direction has an at least substantially rectangular cross-section and in its four corners with fastening means for direct attachment to a component to be cooled or for indirect attachment is provided on a housing containing the component to be cooled. Preferably, the fastening means are formed by mounting holes which are arranged at a standard distance such that the fan can be fixed by means of screws in the computer housing also provided in the standard distance holes. However, the fastening means can also be designed for other types of fastening, for example for snap connections

Such axial fans, which are also referred to as case fans, are well known. They are used in particular in computers for cooling or for dissipating the heat that is emitted by heat-generating components, for example, processors, in particular via heat sinks. For this purpose, a cooling air flow is generated by rotation of the provided with suitably shaped blades or fan blades fan, which is directed in at least substantially axial direction on the heat-releasing and to be cooled component. Alternatively, the fan can also be arranged so that it sucks the ambient air surrounding the heat-dissipating member, so as to dissipate the heat. Such fans may also be connected to other chips, in particular to graphics cards, to hard disk drives and / or to Power supplies are used. In addition, such fans can be used in other devices with heat-generating components, such as projectors.

Fans of the type mentioned thus basically consist of two main main assemblies, namely the fan housing and the rotatable fan wheel unit connected thereto. While the fan housing with its outer areas or with its Luftleitrahmen the installation of the ready-to-use fan, the fan wheel unit ensures with their fan blades by their rotation for the desired movement of the air. The rotational movement of the fan wheel unit is usually brought about by an electric motor arranged coaxially with the fan wheel in or on the fan housing.

Due to the increasing processor performance in computers and the associated increase in heat generation, especially in so-called overclocking of the CPU, the need for effective cooling and thus also the demands on the performance of the fan is growing. The fans must therefore be increasingly operated at higher speeds. At the same time, however, there is an increased demand for low-noise cooling methods and quieter fans.

The high number of revolutions of the impeller from 1000 up to 4000 revolutions per minute generate partly strong vibrations which are transmitted to the fan housing and thus lead to disturbing noise developments. Although this could be counteracted by the use of high-quality and expensive materials limited because, for example, heavy or glass fiber reinforced plastics swing less than lightweight, low-quality plastics. In particular, high-frequency vibrations can be reduced so that the fan quieter and the audible frequencies are lower and thus perceived as less disturbing. Ultimately, however, the disturbing noise developments can not be completely prevented in this way. In addition, this would lead to a disadvantageous increase in the cost of the fan.

The mechanically transmitted to the fan housing during operation oscillations or vibrations increase the overall volume of the fan depending on the speed considerably, since the fan housing of the fan forms a resonator. If the fan is mounted in a computer housing, usually made of sheet steel, which is usually done by a fixed snap or screw connection, the vibrations are transmitted to the then resonating computer case, which again increases the volume. The vibration transmission to the computer case is carried out by the direct contact of the vibrating plastic parts of the fan housing with the computer case. Since a computer housing is a very good sound box, the high-frequency vibrations (structure-borne noise) caused by the fan are clearly audibly amplified by the PC housing.

To prevent the transmission of vibration to the computer case, it is therefore known to fasten the fan with little vibration. The fan is not fastened with metal screws, but attached as a separate mounting means additionally and specially shaped rubber elements, which should prevent the transmission of the fan vibrations to the computer case.

For example, in the DE 201 20 225 U1 proposed to attach a fan of the type mentioned above rubber-elastic elastomeric elements to a component to be cooled in a computer case. In this way, the fan housing is vibration damping attached to a component or the computer case, whereby a certain noise attenuation can be achieved. It is also known to mount the fan housing freely swinging by means of one or more outwardly tensioned rubber cords.

A disadvantage of these solutions, however, is that here too the fan housing still serves as a resonating resonating body and therefore interfering noises are clearly perceived during operation of the fan.

Of particular disadvantage, however, is that in addition to the fan separate elastomer components are needed, which significantly increase the cost and the installation of the fan in the computer is difficult.

Another disadvantage is the additional installation space required for the elastomer components located outside of the fan housing, which represents a considerable problem, especially in the cramped space conditions in a computer housing.

From the US 4 807 718 A is an axial fan with a fan housing is known, which is surrounded by an inertial collar, which consists of two substantially L-shaped collar halves. The fan housing is connected to this inertial collar via an acoustic insulation collar such that the insulation collar is pressed as an elastic damping element by the inertial collar against the outside of the fan housing. The insulation collar is not integrated into the fan housing, but it requires as well as the inertial collar as located outside of the fan housing component additional space, which in turn leads to the aforementioned disadvantages.

Also the GB 2 107 787 A discloses an axial fan with a fan housing surrounded by an external isolation device. This isolation device comprises an outer frame and an inner frame, which are interconnected by an elastic membrane. The inner frame is either attached by screws to the fan housing or designed in one piece with it, wherein the membrane acting as an elastic damping element is not integrated in each case in the fan housing, but this outside surrounds. This in turn requires additional space and is associated with the disadvantages mentioned.

Object of the present invention is therefore to provide an inexpensive to manufacture and easily assembled without additional components fan of the type mentioned above, which has a significantly improved noise reduction in a structurally simple manner and is very quiet in operation, without requiring additional space.

This object is achieved by a fan according to claim 1. Advantageous embodiments and modifications of the invention will become apparent from the dependent claims.

It is essential in the solution according to the invention that four elastic damping elements are integrated into the fan housing of the axial fan, that in each of the four corners an elastic damping element is provided, wherein the fastening means for fixing the axial fan are each arranged within an elastic damping element that the elastic damping element between the fan and the respective fastening means is effective, wherein the damping elements in the axial direction have a greater length than the Luftleitrahmen, so that the damping elements axially project beyond the Luftleitrahmen at both ends by at least 0.5 millimeters, preferably at least 1 millimeter, wherein the fan has fan blades whose surface is provided on one side or on both sides with a plurality of small local elevations and / or small local depressions, in particular with dome-shaped indentations t, and wherein the elastic damping elements are firmly bonded to the Luftleitrahmen, in particular on the outer sides of the Luftleitrahmens.

A significant advantage lies in the fact that due to the effective between the fan and the attachment means for fixing the axial damping damping element, the fan or the Lüfterradeinheit decoupled as a vibration-generating component mechanically completely from a serving for mounting the fan component, in particular from a computer housing receiving the fan is. Therefore, vibrations or vibrations that arise can no longer or at most be transmitted to a significantly reduced extent to an outer component or to a computer housing. Outer components or computer cases are therefore no longer amplifying the resonant body, whereby the volume of the fan during operation is considerably reduced. In particular, in perceived as annoying frequency range as a significant noise attenuation can be achieved.

Another significant advantage is that due to the complete integration of the at least one damping element or the complete integration of all damping elements in the fan neither additional space nor separately to be mounted elastomeric elements are needed. All damping elements are located in the fan housing, so that the axial fan according to the invention can be mounted or attached in exactly the same way and used by the user, as the conventional fan without integrated damping elements.

In this constructively simple manner, an axial fan is created, which not only runs very quietly, but is also inexpensive to produce and quick and easy to install. In the fan according to the invention all the damping elements are integrated into the fan, so that no separate damping components are needed more, via which the fan must be mounted in the computer. The fan according to the invention can therefore be easily mounted in a conventional manner by snap connections or by screw in a computer case, the conventional and standardized mounting Befestigungsbohrüngen can be used. Since all damping means are arranged in the fan housing, on the one hand no additional space is required and on the other hand, an unwanted amplification of the vibrations or an increase in the volume of the fan can be effectively avoided.

Another significant advantage of the inventive solution, in each of which an elastic damping element is provided in the four corner regions, wherein the fastening means are each disposed within an elastic damping element, is that by the elastic decoupling of the fastening elements of the fan housing, a transmission of the vibrations from Fan housing can be particularly effectively reduced or prevented on the surrounding computer case. It is essential in this case that each fastening means which is used for fastening the fan to a component to be cooled or to a computer housing, is accommodated in a damping element, wherein the damping elements are in turn disposed within the axial fan.

Another essential component of the inventive solution in which the damping elements in the axial direction have a greater length than the Luftleitrahmen so that the damping elements project beyond the Luftleitrahmen axially on both end faces, is that can be reliably prevented that the axial fan or its Luftleitrahmen has direct axial contact with a component or housing to which the fan is attached. Only the elastic damping elements can come into direct axial contact with the component to be cooled or with the computer housing. The transmission of vibrations to a component to be cooled or to a computer housing containing the fan can thus be effectively prevented.

The fact that the damping elements can project beyond the Luftleitrahmen axially on both end faces of the fan with both end faces axially applied to a component or a computer case and attached thereto. The vibration decoupling can be done regardless of the orientation of the fan during its assembly.

And the fact that the damping elements project beyond the Luftleitrahmen at the end faces axially by at least 0.5 millimeters, preferably by at least 1 millimeter, a direct contact of the fan housing with surrounding components or computer housings is particularly safe prevented.

Yet another significant advantage of erfindungsaemäßen solution in which the fan has fan blades whose surface is provided on one side or on both sides with a plurality of small local elevations and / or small local depressions, in particular with dome-shaped indentations, is that by the small indentations the air resistance of the fan blades or blades is reduced so that the noise during operation of the fan can be reduced even further regardless of possible vibrations or vibrations.

An additional significant advantage of the solution according to the invention, in which the elastic damping elements are firmly bonded to the air guide frame, in particular on the outer sides of the Luftleitrahmens, is to that a particularly cost-effective production of the axial fans according to the invention can be achieved in particular by gluing or vulcanization.

According to a further advantageous embodiment of the invention, the Luftleitrahmen viewed in the axial direction, at least approximately have an octagonal cross section, wherein the elastic damping elements each have an at least approximately triangular cross-section. Also, the sides facing the damping elements may be rounded or the Luftleitrahmen may have a total of a round cross-section, wherein the damping elements each have an at least approximately triangular cross-section with a concavely curved base side. By this arrangement, a particularly good damping effect is achieved.

The fastening means are preferably formed by bores. Depending on the type and material of the damping element used self-tapping screws can be used to attach the fan. For less stable materials of the damping elements or if a multiple mountability is desired, it is particularly advantageous if the mounting holes each comprise a recorded or cast in the respective elastic damping element, preferably made of metal or plastic, threaded sleeve having an internal thread. In this case, then the internal thread corresponding, in particular metric screws can be used for secure attachment of the fan.

As bearing means, fans and / or roller bearings, in particular ball bearings, are preferably used in fans. In the axial fan according to the invention, however, the bearing means can advantageously also be integrated in the electric motor, so that the bearing means need not be mounted separately but are practically formed by the electric motor. It is also particularly advantageous if the electric motor is designed as a brushless external rotor motor.

Of course, in the context of the present invention, other types of electric motors can be used. For example, the rotor or the rotating magnets of the electric motor can also be arranged in the radially outer region of the fan wheel, so that the stator or the coils of the electric motor are located radially outside the fan wheel.

According to a preferred embodiment of the invention, the elastically resilient damping elements made of rubber or rubber material or of an elastically resilient plastic, in particular made of polyurethane.

The present invention furthermore relates to a computer, in particular a PC, which contains a fan according to the invention of the type described above.

Further advantages and features of the invention will become apparent from the following description and the embodiments illustrated in the drawings.

Figur 1:

schematische Darstellung eines Lüfters gemäß dem vorbekannten Stand der Technik;

Figur 2:

schematische Darstellung einer weiteren Ausführungsvariante eines erfindungsgemäßen Lüfters; und

Figur 3:

schematische Darstellung des Querschnitts des Lüfters aus Figur 2.

Show it:

FIG. 1:

schematic representation of a fan according to the prior art;

FIG. 2:

schematic representation of another embodiment of a fan according to the invention; and

FIG. 3:

schematic representation of the cross section of the fan off FIG. 2 ,

The in FIG. 1 schematically shown axial fan 1 of conventional design has a manufactured from plastic cuboid fan housing 2, which in each case has a mounting hole as a fastening means 3 for attachment in a computer case, not shown here in the corners of its outer housing portion. From the outer housing portion extending four straight connecting arms 4 inwardly, at its inner End in a circular trained central storage area 5 of the fan housing 1 open.

The connecting arms 4 extend in the embodiment shown here tangential to the bearing area 5. However, they can also extend in other directions, for example radially. Likewise, the connecting arms 4 can also be bent and / or provided in a different number.

At the central storage area 5, a fan 6 is rotatably mounted. For this purpose, the hub 7, from which the fan blades 8 extend outwardly, stored in non-illustrated bearing means. To drive the fan wheel 6, a not-shown electric motor is provided in the fan housing 2, which is arranged completely or partially in or on the hub 7 and the storage area 5.

The fan 6 is thus connected via the bearing means and the storage area 5 and the connecting arms 4 to the fan housing 2. By its rotation, the fan 6 generates the air movement required for cooling, the outer region of the fan housing 2 serves as Luftleitrahmen for the air flow. In this respect, fans 1 are generally known.

In order to allow a particularly quiet fan operation is inventively provided that within the fan housing 2 between the fan housing 2 and the bearing means for the fan 6 elastically resilient damping elements 9 are arranged as vibration buffer.

At the in FIG. 2 illustrated embodiment, four damping elements 9 are arranged in the four corners of the fan housing 2. The damping elements 9 are then vulcanized onto the outer sides of the Luftleitrahmens 10. The Luftleitrahmen 10 of the fan housing 2 has viewed in the axial direction on the inside a surrounding the fan 6 round cross section and the outside a substantially octagonal cross-section, the four the Damping elements 9 facing sides 11 are made shorter than the four outer sides of the fan housing 2 forming sides 12th

As in FIG. 3 can be seen, the damping elements 9 in the axial direction have a greater length than the Luftleitrahmen 10 or as the fan housing 2. The damping elements 9 have a length of 25 mm, which corresponds to a standard width of axial fans for PCs, while the Luftleitrahmen 10 only one Width of 23 mm, so that the damping elements 9 project beyond the Luftleitrahmen 10 at both ends axially by one millimeter.

The fastening means 3 are also formed here by fastening bores, which are each arranged within an elastic damping element 9. In order to ensure a particularly secure and multiple attachment of the fan 1, each made of metal threaded sleeve 13 is cast with an internal thread in the respective elastic damping element 9 at each mounting hole 3, so that the attachment of the fan 1 in a computer case by means of metric Screws can be carried out very easily and safely.

In the embodiment according to the invention according to the FIGS. 2 and 3 four elastic damping elements 9 are integrated into the axial fan and arranged so that they are effective between the fan 6 and the mounting holes 3 for fixing the axial fan 1.

Claims (5)

1. Axial-flow fan (1) for the ventilation of heat generating components, in particular computer fans for the ventilation of electrical and/or electronic components in a computer, comprising a fan housing (2) with an air guide frame (10), which may be axially flowed-through, in which a fan impeller (6) is rotatably mounted, the fan housing (2) having in the axial direction an at least substantially rectangular cross-section and being provided in the four corner regions thereof with fastening means (3), in particular with fastening holes, for directly fastening to a component to be cooled or for indirectly fastening to a housing containing the component to be cooled,
   characterised in that
   four elastic damping elements (9) are incorporated in the fan housing (2) of the axial-flow fan (1) such that one elastic damping element (9) is provided in each of the four corner regions respectively,
   the fastening means (3) for fastening the axial-flow fan (1) being respectively arranged inside an elastic damping element (9) such that the elastic damping element (9) is effective between the fan impeller (6) and the respective fastening means (3),
   the damping elements (9) being of greater length in the axial direction than the fan guide frame (10), so that the damping elements (9) axially project beyond the air guide frame (10) on both front faces by at least 0.5 millimetres, preferably by at least 1 millimetre,
   the fan impeller comprising fan blades, of which the upper surface is provided on one side or on both sides with a plurality of small local raised portions and/or small local recesses, in particular with spherical-shaped notches,
   the elastic damping elements (9) being integrally fastened to the air guide frame (10), in particular to the outer faces of the air guide frame (10).
2. Fan according to claim 1, characterised in that, viewed in the axial direction, the air guide frame (10) has at least approximately an octagonal or round cross-section and in that the elastic damping elements (9) respectively have an at least approximately triangular cross-section and/or an at least approximately triangular cross-section with a concave curved bottom face.
3. Fan according to one of the preceding claims, characterised in that the fastening means (3) are formed by holes which comprise one respective threaded bush (13) with an internal thread, received or cast in the respective elastic damping element (9) and preferably consisting of metal or plastic.
4. Fan according to one of the preceding claims, characterised in that the elastic damping elements (9) consist of rubber or caoutchouc material or an elastically flexible plastic.
5. Computer, in particular PC, characterised in that it contains a fan (1) according to one of the preceding claims.

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