DE1503489B2

DE1503489B2 - STORAGE FOR BLADES OF LARGE AXIAL FANS

Info

Publication number: DE1503489B2
Application number: DE19661503489
Authority: DE
Inventors: Fritz Dipl.-Ing.; Brobeck Helmut; 6710 Frankenthal Bub
Original assignee: Kuehnle Kopp and Kausch AG
Current assignee: Howden Turbo GmbH
Priority date: 1966-02-01
Filing date: 1966-02-01
Publication date: 1972-10-12
Also published as: BE693378A; NO127120B; NL6701532A; DK124624B; GB1102110A; DE1503489A1; FR1509493A

Description

3 43 4

Metall-Gummi-Federelementes trägt die Klemm- da durch die Federelemente 8 die Lage des Holms nabe 9, die auf dem Holm 3 des Flügels aufgeklemmt auch in Umfangsrichtung genügend festgelegt ist.
ist. Damit ist der Flügelhohn durch das Federelement Als federndes Element können natürlich auch am Nabenkranz abgestützt. Die Gummi-Feder- andere Einrichtungen als die in dem Ausführungselemente 8 haben in unserem Beispiel nach F i g. 2 5 beispiel dargestellten Metall-Gummi-Federelemente eine langgestreckte rechteckige Form, wobei sich die benutzt werden; beispielsweise Stahlfedern. Die längere Seite in Umfangsrichtung erstreckt. Dadurch Metall-Gummi-Federelemente eignen sich jedoch für hat die federnde Abstützung in Richtung der Achs- die Anwendung bei dieser Flügellagerung in besondeebene des Laufrades eine wesentlich größere Weich- rem Maße, weil sie neben der Einfachheit der Ausheit als in Umfangsrichtung; das heißt die Aufhän- io führung auch eine gewisse Dämpfung besitzen und gung des Flügels ergibt in der vertikalen Ebene eine darüber hinaus relativ große Federwege; das heißt wesentlich niedrigere Eigenfrequenz als in der Um- eine geringe Steifheit bei kleinen Abmessungen erfangsrichtung, unabhängig davon, daß auch die Flü- möglichen.The metal-rubber spring element carries the clamping because the spring elements 8 position the spar hub 9, which, when clamped on the spar 3 of the wing, is also sufficiently fixed in the circumferential direction.
is. This means that the wing mockery is supported by the spring element. As a resilient element, it can of course also be supported on the hub rim. The rubber spring devices other than those in the execution elements 8 have in our example according to FIG. 2 5 exemplified metal-rubber spring elements have an elongated rectangular shape, which are used; for example steel springs. The longer side extends in the circumferential direction. As a result, metal-rubber spring elements are suitable, however, for the resilient support in the direction of the axis - the application in this wing mounting in a special plane of the impeller has a much greater degree of flexibility because, in addition to the simplicity of the unity, they are more flexible than in the circumferential direction; This means that the suspension guide also has a certain damping and movement of the wing results in a relatively large spring deflection in the vertical plane; This means that the natural frequency is much lower than in the surrounding area.

gelprofilform unterschiedliche Eigenfrequenzen in den Die Erfindung ermöglicht es, die Flügel großer verschiedenen Richtungen ergibt. 15 Axialventilatoren so in der Laufradnabe zu lagern, F i g. 2 zeigt weiterhin, wie die Klemmnabe 9 durch daß die Eigenfrequenz der Flügelschwingung insbe-Schrauben 10 zusammengehalten wird. Die Schrau- sondere in Richtung der Achsebene bzw. senkrecht ben 7 sind in der Tragplatte 6 in Langlöchern 11 mit zur Profilebene des Flügels so niedrig liegt, daß gekreisförmiger Mittellinie so angeordnet, daß der Flü- fährliche Resonanzen nicht auftreten. Eine solche gelholm 3 mit dem ganzen Federelement 8 um den 20 Lagerung ist insbesondere dort erforderlich, wo eine Winkel β um seine Achse gedreht werden kann. Da- Erregung durch ungleichmäßige Anströmung erfolgt, mit besteht die Möglichkeit, den Anstellwinkel des z. B. bei Kühlturmlüftern. Die Erfindung ermöglicht Flügels den Erfordernissen des Betriebes entspre- es aber, bei entsprechender Bemessung der Federchend zu verstellen, ohne die Federungseigenschaften elemente auch in Umfangsrichtung eine Abstützung richtungsbezogen auf den Flügel selbst zu ändern. Es 25 zu erreichen, die die Gefahr von Resonanzen bei ist jedoch auch möglich, den Anstellwinkel durch Torsionsschwingungen des gesamten Ventilatoraggre-Drehen des Flügels in der Klemmnabe 9 zu ver- gates vermeidet. Dabei wird bei einzeln vorkommenändern, wobei die Federungseigenschaften in bezug den stoßartigen Ausschlägen die Möglichkeit einer auf die Laufradachse unverändert bleiben. Die an größeren Durchfederung und eines weichen Abfander Nabe angebrachten Anschlagplatten 12 begren- 30 gens des Ausschlages gegeben. Auch kann darüber zen gegebenenfalls die in Umfangsrichtung möglichen hinaus ein fester Anschlag angeordnet werden. Durch Ausschläge des Flügels. Dabei sollen aber diese die Erfindung wird daher im ganzen eine möglichst Platten 12 keine Führung in senkrechter Richtung geringe Beanspruchung des Flügelholms bei geringdarstellen und sind auch hierfür nicht erforderlich, stem Bauaufwand erreicht.Gelprofilform different natural frequencies in the The invention makes it possible to produce the wings of large different directions. 15 axial fans to be mounted in the impeller hub, F i g. 2 also shows how the clamping hub 9 is held together by the natural frequency of the wing oscillation, especially screws 10. The special screws in the direction of the axial plane or perpendicular ben 7 are located in the support plate 6 in elongated holes 11 with the profile plane of the wing so low that the circular center line is arranged so that dangerous resonances do not occur. Such a gelholder 3 with the entire spring element 8 around the 20 mounting is particularly necessary where an angle β can be rotated about its axis. Since excitation takes place through uneven flow, there is the possibility of changing the angle of attack of the z. B. with cooling tower fans. The invention enables the wing to meet the requirements of the operation, but to adjust the spring with appropriate dimensioning, without changing the suspension properties elements in the circumferential direction, a support based on the direction of the wing itself. It is also possible, however, to avoid the risk of resonance in the case of the angle of attack due to torsional vibrations of the entire fan assembly rotating the blade in the clamping hub 9. In this case, individual occurrences change, with the suspension properties in relation to the shock-like deflections and the possibility of an impact on the wheel axle remaining unchanged. The stop plates 12 attached to the larger spring deflection and a soft spacer hub limit the deflection. In addition, a fixed stop that is possible in the circumferential direction can also be arranged above this. Due to wing deflections. In this case, however, the invention is therefore as a whole as possible panels 12, no guidance in the vertical direction, low stress on the wing spar with low and are also not required for this.

Hierzu 1 Blatt Zeichnungen1 sheet of drawings

Claims

1 2 is relatively small in terms of length, and an outright suspension is not to be expected under these conditions, since rubber is not compressible. Even

1. Storage for blades of large size, the ring shape of the elastic material does not allow axial fans, especially for cooling towers 5 coordination of a spring constant after different ventilation, characterized in that directions. The absorption of the moments from that the resilient elements (8) on the hub rim of the flow around the wing must be arranged in the short (6, 6 a) and in the axial direction of the metal-rubber sleeve, because a tight impeller have a different spring rate The spherical cap arranged behind the bushing serves as a circumferential direction. io only as a counter bearing for one in the longitudinal direction of the

2. Storage for wing blades according to claim 1, wing by mercury, which under centrifugal force thereby characterized in that the resilient EIe- effect is, generated force that the centrifugal force of the elements (8) in the axial direction of the impeller cancels a wing.

have significantly greater softness than in the subject of the application is on the other hand

Circumferential direction. 15 is based on the task of a bearing for wing

3. Storage for blades according to claim 1 blades of large axial fans in the impeller or 2, characterized in that to create for the hub in which a resonance excitation is supported on the hub rim metal-rubber-spring - probably for the oscillation in the axial direction as in elements (8) are used. Circumferential direction is prevented and at the same time

4. Storage for wing blades according to claim 1 20 large moments from the flow forces on the wing or 3, characterized in that the spring can be added.

elements (8) on the hub rim at an angle (/?) The invention solves this problem with a position

are attached rotatably about the spar axis. tion for blades of large axial fans,

in which the inner end of a vane spar spherically 25 held movably in an impeller hub and the

Holm is supported in the hub by resilient elements, in that the resilient elements on Hub rim are arranged and have a different spring constant in the axial direction of the impeller than The invention relates to the storage for wing 30 in the circumferential direction.

blades of large axial fans, in particular The advantage of the storage according to the invention is

for cooling tower ventilation, in which the inner end that large centrifugal forces flawlessly through the spherical a wing spar can be accommodated spherically movable in a barrel storage, with zwiradnabe held and the spar in the hub see through this and the support on the hub rim resilient elements is supported. 35 such a large distance is executed that the

Such a mounting must of course be designed in such a way that the flow forces around the wing absorb the flow forces and moments or absorb the forces of the resilient ones. But it should also be suitable and supported by a correspondingly long lever arm so that it is kept small vibrations to the pivot point in the ball, the wing by periodically acting forces 4 ° The resilient elements are avoided to avoid. It is known to suspend the blades from the axially balanced flow of resonance vibrations through turbomachinery and swing them in the two main directions (axial and vice versa Mistake,
so in the plane of rotation (see German patent specification 45 The drawing explains the 'invention on hand

1 167 852). of an embodiment. 1 shows a Furthermore, through the USA patent specification, a radial section through one half of the impeller hub,

2 416 178 an embodiment of a bearing for wings, the wings themselves not being shown, FIG. 1 line of the blades indicated by a universal joint on the hub 50 AB, the angle of inclination α of the blade axis being kept wreath of the impeller, the large one being neglected to clarify the illustration. Angular mobility of this joint by rubber According to Fig. 1, the hub 1 of the impeller with the buffer, which have a damping effect, a bushing 2 is set on the not shown in the drawing. The action of these links is attached to the vertical shaft of the axial fan. 3 is the support or resilient mounting of the wing, 55 is the spar of the wing, but with the angle of inclination α it is very small because the rubber buffer is inclined relative to the horizontal. As a result of this, in addition to the pivot points in the area of the inclination, a torque compensation is attached between the cardan joint, so that there is no attacking suspension for the centrifugal force of the wing and the effect in the present case in the sense of a suspension that is coordinated with the axis at a certain frequency, for example from top to bottom Lever arm 60 brought about allelic buoyancy forces, so that the is available. It is also not evident that the stress on the wing spar 3 is as low as possible for the elements in the various directions (axial. The wing spar is at its inner end direction and circumferential direction) different tuning is held in the spherical bearing 4, the bearing should have. carrier 5 with the impeller hub 1, for example

US Pat. No. 2,319,335 shows a layer 65 weld is firmly connected. On the hub rim 6 a tion, in which the very short spar of a propeller, the support plate 6 is attached, which is held with the help of the wing in a hollow cylindrical metal-rubber screws 7, the left metal plate of the metal sleeve. The wall thickness of the rubber is rubber spring element 8 carries. The right plate of the