WO2013007537A2 - Production of an air flow by means of vibrations - Google Patents

Abstract

The invention relates to a turbomachine (H) comprising an air flow generation unit (1) which can be excited to create vibrations and which includes a Chladni resonator (3, 9) having at least one resonantly excitable plate (3). An illumination device (R) includes at least one turbomachine (H) for cooling at least one light source (L). The method, which involves the exciting of a plate (3) of a Chladni resonator (3, 9), is used to produce a cooling air flow (K). The invention can be advantageously used in particular for cooling LED lights and/or luminaires equipped with LED lights.

Description

description

Generation of an air stream by means of oscillations The invention relates to a turbomachine with a

A vibration excitable air flow generating unit, wherein the air flow generating unit comprises a Chladni resonator having at least one resonant excitable plate. The invention further relates to a lighting device, comprising at least one such flow machine for cooling

at least one light source. The invention also relates to a method for generating an air flow, in particular

Cooling air flow, by stimulating a

 Air flow generating unit to vibrations. The invention is particularly advantageously applicable for cooling of LED lamps and / or lamps that can be equipped with them.

DE 10 2008 038 549 A1 discloses a method for generating an air flow by means of ultrasound, specifically for the cooling of small electronic circuits, for example electronic ballasts. Described is a device for generating an air flow with a

Excitation element and a vibrating element, wherein the

Oscillating element of the excitation element to vibrations can be excited and the vibrations lead to an air flow. In particular, a connecting element between the

Provided excitation element and the vibrating element and be mechanically connected to both. The connecting element may be formed frusto-conical and be completed at its lid and bottom surface of the vibrating element and the excitation element. Specifically, it is proposed that a

piezoelectric actuator with a front mounted

Stimulate and operate vibration diaphragm with ultrasonic frequencies. The vibrations of the vibrating diaphragm create an air flow which cools the circuit.

Furthermore, natural vibrations of plates are known. This solid forms on the plate for solid boundary conditions Positions for resonant oscillation maxima and

Vibration minima, which e.g. can be made visible by sprinkling the plate with sand (creation of Chladnic sound figures). A resonantly oscillating or intrinsically vibrating plate may also be referred to as a Chladni resonator.

It is the object of the present invention to provide a particularly simple and compact way of generating a

To provide air flow by means of mechanical vibrations.

This object is achieved according to the characteristics of the independent

Claims solved. Preferred embodiments are

in particular the dependent claims.

The object is achieved by a turbomachine with an airflow generating unit that can be excited to oscillate, wherein the airflow generating unit has a Chladni resonator with at least one resonantly excitable plate.

Under a turbomachine can in particular a

Gas engine to be understood in the one

Energy transfer between gas (especially air) and

Machine takes place in an open space through a flow according to the laws of fluid dynamics via the detour of kinetic energy.

This turbomachine has the advantage that its air flow generating unit is particularly flat ausgestaltbar. Also like the air flow generating unit without special

 Extensive efforts be made. In addition, this turbomachine can be simple and inexpensive

getting produced. The turbomachine may be in addition to the at least one air flow generating unit, e.g. also electrical connections, a holder, air guiding devices and / or a driver for the electrical operation of

Air flow generating unit, etc. have. Of course, the turbomachine can bring or promote another gaseous medium than air to the flow. Thus, the description of this invention is not limited to "air," and a reference to air may include, in particular, any gaseous medium.

It is a preferred for enabling a particularly compact and precisely energizable turbomachine

Embodiment, that the plate can be excited by means of at least one volumetric actuator. Under a

In particular, any actuator that can change its material volume by means of an external control signal (e.g., a voltage, a magnetic field) can be understood as a volumetric actuator. For example, a volumetric actuator may include an electrostrictive actuator or a magnetostrictive actuator. Due to its robustness, compact design, its comparatively inexpensive

However, production and its easy activation, a piezoelectric actuator or piezoelectric actuator is particularly preferred. The actuator can in particular be glued to the plate.

It is still an embodiment that the plate can be excited by means of a matrix-like array of actuators. Thus, particularly uniform or deliberately uneven vibration amplitudes can be achieved across the plate.

 In particular, the actuators may be individually or in groups controllable to produce a predetermined resonance pattern. Alternatively, however, the plate may also be e.g. be stimulated by a, in particular central, actuator to natural oscillations or to resonance.

It is yet a further embodiment that the at least one volumetric actuator is configured as a piezoactuator plate. So can a particularly flat and

inexpensive air flow generating unit can be provided. It is also an embodiment that the plate with a frequency of at least about 50 kHz, in particular of

at least about 100 kHz, in particular of at least about 200 kHz, can be excited. Thus, a strong air flow can be generated at an (ultrasonic) frequency that is no longer audible for humans and most animals.

It is also an embodiment that the plate has a

Metal plate is. A metal plate is particularly easy excitable to natural vibrations with high amplitudes, inexpensive available and simply variable in their properties

producible.

It is still an embodiment that the plate a

Plastic plate is, which can be particularly light, durable and inexpensive. It is a development that the plastic plate is connected to a piezoelectric plastic film. The piezoelectric plastic film serves as an actuator or actuator field and can in particular with the

Plastic plate as a large-scale layer composite

be connected. This enables a particularly flat and robust air flow generating unit. The piezoelectric plastic film may consist in particular of polyvinylidene fluoride (abbreviation PVDF).

It is still an embodiment that the plate a

Ceramic plate is. The ceramic used may in particular be a ceramic with a low acoustic attenuation. If the at least one actuator, in particular piezoelectric actuator, is a ceramic actuator, the at least one actuator can be sintered to the plate to form a piece.

It is also an embodiment that the plate

is swingably suspended on webs. Thus, a simple suspension and alignment of the plate can be achieved without a substantial restriction of its ability to vibrate. The webs can hold or fasten the plate to a frame. In particular, the frame and the plate can off be worked out a full-surface layer or (semi-finished or output) plate, in particular by introducing corresponding recesses, for example by means of a

mechanical material removal or by means of a

Laser ablation, in particular laser cutting.

 In particular, in this embodiment, but also quite generally, the air flow generating unit may have a plurality of resonant excitable plates. It is an advantageous for a little disturbing suspension

Embodiment that the plate is a polygonal plate at the corners attach the webs. However, the plate may be e.g. also be a round or oval plate, etc., in which case the webs can then in particular be equidistant.

It is yet another embodiment that at least one region of the plate, which forms a maximum vibration, a Übertragerelement is present, which mechanically connects this area with a vibration unit, so that the vibration unit can be excited from this area to vibrations. So the transformer element may vibrate particularly strong, thus causing a particularly strong vibration of the vibration unit and thus a particularly strong flow of cooling air.

It is still another embodiment that at least a portion of the plate, which is located between a

Vibration maximum and a vibration minimum is present, a transformer element is present, which mechanically connects this area with a vibration unit, so that the vibration unit from this area to vibrations

is excitable. Thus, the air flow generating unit can be adapted to a high quality factor, which can also cause a particularly strong vibration of the vibration unit and thus a particularly strong flow of cooling air.

It is still a further embodiment that at least one region of the plate, which is also a Minimum vibration is located, a Übertragerelement is present, which mechanically connects this area with a vibration unit, so that the vibration unit of this area to vibrations can be excited. Thus, the air flow generating unit can also be at a high

Quality factor to be adjusted.

The positions of the vibration minima and vibration maxima forming on the plate during operation need not coincide with a position of the at least one actuator. It is a preferred development for a particularly durable connection between the at least one actuator, in particular adhered actuator, and the plate, that the actuator is arranged in the region of a vibration minimum.

It is a development that the transformer element has a conical basic shape, which tapers from the plate to the vibration unit. This can be a

Amplification amplitude at the vibration unit to be amplified.

The oscillation unit protrudes laterally beyond its contact surface with the transmitter element for particularly effective generation of an air flow.

It is a development which is particularly preferred for a simple and inexpensive production of the transformer element that at least the transformer element has a plurality of layers or is composed of such layers (ie is a layered body). An advantage consists in the production of at least the transformer element by simple layering, in particular by means of pre-structured layers or

Plates, instead of a complex machining of a solid material. Among other things, the transformer element makes use of the fact that an outer contour which is favorable for the function does not necessarily have to be smooth, since in the case of typical, sufficiently large wavelengths generated by the plate of the Chladni resonator, the Suggestions about the existing in this structure stages away.

It is a preferred embodiment for simple and compact production that the transformer element and the vibration unit as a common laminated body

be present, the vibration unit is thus also constructed of one or more layers. It is also an embodiment that the plate as

 Having air channels serving recesses. This improves a uniform air supply across the plate, which in turn enables more uniform airflows across the surface of the plate.

The object is also achieved by a lighting device, comprising at least one turbomachine for cooling at least one light source, wherein the at least one

Turbomachine a turbomachine as described above.

The lighting device may be a lamp, a module, a

Be a light or a lighting system. For example, the lighting device may be a luminaire, e.g. a ceiling light, which has a reflector. The reflector (or a reflector of another lighting device) can be used as the

Serving plate of the Chladni resonator and thus assume both a reflection function and a cooling function. The light source may in particular be a semiconductor light source. Preferably, the at least one

Semiconductor light source at least one light emitting diode. at

If several LEDs are present, they can be lit in the same color or in different colors. A color may be monochrome (e.g., red, green, blue, etc.) or multichrome (e.g., white). This can also be done by the at least one

LED emitted light is an infrared light (IR LED) or an ultraviolet light (UV LED). Several Light emitting diodes can produce a mixed light; eg a white mixed light. The at least one light-emitting diode may contain at least one wavelength-converting phosphor

(Conversion LED). The phosphor may alternatively or additionally be arranged away from the light-emitting diode

 ("Remote Phosphor"). The at least one light-emitting diode can be in the form of at least one individually housed light-emitting diode or in the form of at least one LED chip. Several LED chips can be mounted on a common substrate ("submount"). The at least one light emitting diode may be equipped with at least one own and / or common optics for beam guidance, e.g. at least one Fresnel lens,

Collimator, and so on. Instead of or in addition to inorganic light emitting diodes, e.g. based on InGaN or AlInGaP, organic LEDs (OLEDs, for example polymer OLEDs) can generally also be used. Alternatively, the at least one semiconductor light source may be e.g. have at least one diode laser. The object is further achieved by a method for

Generating a cooling air flow, the method a

Stimulating a plate of a Chladni resonator comprises. This method allows the same advantages as the

Lighting device and can be configured analog.

For example, it may be an embodiment that movement of the excited plate of the Chladni resonator by means of a Übertragerelements on a vibration unit

is transmitted, wherein the moving vibration unit generates the cooling air flow.

The above-described characteristics, features and advantages of this invention as well as the manner in which they are achieved will become clearer and more clearly understood

In connection with the following schematic description of exemplary embodiments that are associated with the

Drawings are explained in more detail. It can to Clarity identical or equivalent elements must be provided with the same reference numerals.

Fig.l shows in a view obliquely from above one

Exploded view of an air flow generating unit according to a first embodiment;

2 shows a sectional side view of a

Section of the air flow generating unit in the region of a transformer element;

3 shows a Chladni plate the

 Air flow generating unit in plan view; 4 shows a top view of a section of a

Air flow generating unit according to a second

Embodiment;

5 shows a lighting device with a

Air flow generating unit according to the first or the second embodiment.

Fig.l shows in a view obliquely from above one

Exploded view of an air flow generating unit 1 according to a first embodiment. The

 Air flow generating unit 1 is composed of a plurality of layered plates 3 to 7.

A bottom in this view, metallic plate 3

("Chladni plate") is a full-surface plate. The Chladni plate 3 has thirty-five at its bottom

circular disk-shaped (plate-shaped) piezoelectric actuators 9, which may be glued to the Chladni plate 3, for example. The Chladni plate 3 and the piezo actuators 9 form a Chladni resonator 3, 9, wherein the piezo actuators 9 can excite the Chladni plate 3 to natural oscillations. The piezo actuators 9 are here in an mxn matrix pattern with, for example, m equal to seven and n equal to five

arranged. The piezo actuators 9 can via electrical

Signals are activated, with no electrodes, electrical insulation, electrical

Connections, etc. are shown, even if they may be present.

On the Chladni plate 3 four more plates 4 to 7 are stacked applied. Each of the plates 4 to 7 is

structured such that a plurality of partially separated, circular portions 4a to 7a are present. The

Subareas 4a to 7a are arranged analogously to the piezo actuators 9 in a congruent 7x5 matrix pattern. The portions 4a to 7a are arranged in particular in the same pattern on the plates 4 to 7, that superposed portions 4a to 7a and a

arranged underneath piezoelectric actuator 9 are arranged concentrically with each other.

The subregions 4a to 7a are integrally connected to a remaining layer frame 4b to 7b via in each case three webs 8. By the webs 8 are the

Subareas 4a to 7a capable of oscillation in the respective

Layer frame 4b to 7b held. The

 Vibration properties of the subregions 4a to 7a are then also determined by the properties of the webs 8, e.g. their number, dimensions and / or material determined. For example, the number of lands 8 per subregion 4a to 7a can be variably selected, e.g. in terms of a desired strength.

The partial separation of the subregions 4a to 7a can

For example, by introducing three annular sector-shaped recesses 11 per portion 4a to 7a in one

full-surface plate 4 to 7 are performed. The

 Partial separation may e.g. by means of an etching process, a stamping process or a laser structuring,

especially laser cutting, process from the full-surface Plate 4 to 7 can be achieved. Alternatively, at least one of the plates 4 to 7 may already be in the partially separated

Parts 4a to 7a having been produced.

The sections 4a, 5a, 6a of the first three plates

("Übertragerplatten") 4 to 6 above the Chladni plate 3 each form a transformer element 4a, 5a, 6a. The

Although sections 4a, 5a, 6a have the same circular basic shape, but with increasing distance from the

Chladni plate 3 smaller in area (here: in diameter). The shape of the transformer element 4a, 5a, 6a is thus stepped frustoconical. The subregions 7 a of the top plate 7

 ("Vibration plate") have a larger diameter than the portions 6a of the directly underlying

Connecting plate 6. The sections 7a form a

respective vibration unit.

The plates 3 to 7, in particular 4 to 7, may be made of a same material, or the connecting plates 4 to 6 may consist of a same material and the

Vibration plate 7 may consist of a different material. The plates 4 to 7 may be made of metal, plastic and / or ceramic.

To produce the air flow generating unit 1, the plates 3 to 7 are connected to a solid layer stack.

This bonding can be achieved for example by gluing, for example by means of epoxy resin. Metallic plates 3 to 7 can also be soldered together, ceramic plates 3 to 7 are sintered together. Fig. 2 shows a sectional side view of a section of the air flow generating unit 1 in the region of a transformer element 4a to 6a. In operation, by applying an electrical signal, in particular an alternating voltage, to the piezoelectric element 9, this stimulates mechanical oscillations (in particular acoustic vibrations, in particular ultrasonic vibrations of at least 100 kHz). The vibrations are transmitted to the Chladni plate 3, which thereby

Natural oscillations is stimulated. The natural oscillations of the Chladni plate 3 are further transmitted to the transformer element 4a, 5a, 6a, and from there on to the

Oscillation unit 7a. The transformer element 4a, 5a, 6a reinforces a due to its tapered shape

Vibration amplitude at the subregion or the

Oscillation unit 7a. The oscillation unit 7a in turn generates a desired air flow.

In particular, the material and / or the thickness of the partial regions 4a to 6a and / or the partial region 7a can be designed for a low vibration damping and / or for a strong excitation of the partial region 7a.

That the outer contour of the Übertragerelements 4a, 5a, 6a is formed in stages, is not a disadvantage, because the thickness is typically small compared to a wavelength of a natural vibration generated by the Chladni plate 3 and thus is not resolved by the mechanical shaft.

3 shows the Chladni plate 3 of

 Air flow generation unit 1 in plan view. The Chladni plate 3 has a rectangular shape and is connected at its corners via webs 12 with a frame 13. By means of the webs 12 remains the edge of the Chladni plate. 3

capable of vibrating. The covered by the piezo actuators 9

Regions 14 of the Chladni plate 3 are dashed

drawn

In the air flow generation unit 1, the more

Transmitter elements 4a, 5a, 6a and vibration units 7a in a frame 4b to 7b, it can at a large lateral expansion with many transformer elements 4a, 5a, 6a and vibration units 7a happen that a

Air supply to the vibration units 7a is not uniform, since at the edge of the air flow generating unit 1 located vibration units 7a are better supplied with air than internally arranged vibration units 7a. However, this may decrease the efficiency of the airstream generation and hence the cooling performance from outside to inside. To add an air supply or air forward to the

 To improve vibration units 7a, in particular to uniform, can, as the basis of

 Airflow generating unit 15 shown in Figure 4, laterally of the occupied by the piezo actuators 9 areas 14 of the Chladni plate 3 air ducts 16 may be present in the air flow generating unit 15. The air channels pass through the stacked layer frames 4b to 7b. Thereby, air from a rear side of the air flow generating unit 15 to the

Front side, which has the vibration units 7a, sucked or tracked.

A contour of the air ducts 16 can, as shown in Figure 4, for a good utilization of space substantially the shape of the

adjacent areas 14 of the Chladni plate 3 correspond. Alternatively, the contour of the air channels may be shaped, in particular, by simple geometric shapes, e.g. a circular shape, oriented to simplify manufacture.

Otherwise, the airflow generating unit 15 may be formed in particular like the airflow generating unit 1.

5 shows a lighting device R with a

Turbomachine H, which has an air flow generating unit 1 or 15. The lighting device R furthermore has two semiconductor light sources, in particular LEDs, L, which are cooled by means of a cooling air flow K generated by the air flow generation unit 1 or 15. A turbomachine H having the air flow generating unit 1 can be used in addition to the

Airflow generating unit 1 e.g. also electric

Connections, louvers, a holder and / or a driver for electrical operation of the piezoelectric actuators 9, etc. (o.Fig.) Have.

Although the invention is shown in detail by the

Embodiments have been further illustrated and described, the invention is not limited thereto and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

So like the transformer elements 4a, 5a, 6a and the

Vibration units 7a also laterally offset to the

Piezo actuators 9 may be arranged.

In particular, the transformer elements 4a, 5a, 6a may rest on areas of the Chladni plate 3, which are not covered by (also on the other side) piezoactuators 9. Thus, a particularly high oscillation amplitude of the Chladni plate 3 can be exploited if the regions 14 regions of low oscillation amplitude (including a

Vibration minimums). At the shown

For example, exemplary embodiments may include transformer elements 4a, 5a, 6a arranged in a 6 × 4 matrix field between the free points present in the 7 × 5 matrix field

be arranged. However, the transformer elements 4a, 5a, 6a may overlap with the areas 14 covered by piezoactuators 9 or even rest thereon, as shown above. Although the regions 14 may have a comparatively low oscillation amplitude, but the transformer elements 4a, 5a, 6a resting thereon may cause a particularly high quality factor.

In general, the transformer elements 4a, 5a, 6a and the vibration units 7a on areas of the Chladni plate 3, which correspond to areas with oscillation maxima, areas with oscillation minima or areas between them.

LIST OF REFERENCE NUMBERS

1 air flow generation unit

3 Chladni plate

 4 plate

 4a subarea

 4b layer frame

 5 plate

 5a subarea

5b layer frame

 6 plate

 6a subarea

6b layer frame

 7 plate

7a subarea

 7b layer frame

 8 footbridge

 9 piezoelectric actuator

11 recess

12 footbridge

 13 frames

 14 covered area

 15 air flow generation unit

16 air duct

 R lighting device

 H turbomachine

 L LED

K cooling air flow

Claims

claims 1. Turbomachine (H) with a to vibrations  excitable air flow generating unit (1; 15), wherein the air flow generating unit (1; 15) a Chladni resonator (3, 9) with at least one resonant  excitable plate (3). 2. Turbomachine (H) according to claim 1, wherein the plate (3) by means of at least one volumetric actuator, in particular piezoelectric actuator (9), can be excited. 3. Turbomachine (H) according to claim 2, wherein the plate (3) by means of a matrix-like array of actuators (9) is excitable. 4. turbomachine (H) according to any one of claims 2 or 3 wherein the at least one volumetric actuator is designed as a piezoactuator plate (9). 5. Turbomachine (H) according to one of the preceding  Claims, wherein the plate (3) with a frequency of at least about 50 kHz, in particular of at least about 100 kHz, in particular of at least about 200 kHz, can be excited. 6. Turbomachine (H) according to one of the preceding  Claims, wherein the plate (3) is a metal plate. 7. turbomachine (H) according to any one of claims 1 to 5, wherein the plate (3) is a plastic plate, which with a piezoelectric plastic film,  especially from polyvinylidene fluoride, is connected. 8. Turbomachine (H) according to one of the preceding Claims, wherein the plate (3) is swingably suspended on webs (12). Turbomachine (H) according to claim 8, wherein the plate (3) is a polygonal plate, at the corners of the webs (12) attach. Turbomachine (H) according to one of the preceding claims, wherein at least a portion of the plate (3), which forms a vibration maximum Transducer element (4a, 5a, 6a) is present, which mechanically connects this area with a vibration unit (7a), so that the vibration unit (7a) is excitable from this area to vibrations. Turbomachine (H) according to one of the preceding claims, wherein at least a portion of the plate (3), which is located between a vibration maximum and a minimum vibration, a transformer element (4a, 5a, 6a) which mechanically connects this region with a vibration unit (7a), so that the vibration unit (7a) can be excited to oscillate from this region. Turbomachine (H) according to one of claims 10 or 11, wherein the plate (3) serving as air ducts Having recesses (11). Lighting device (R), comprising at least one Turbomachine (H) for cooling at least one Light source (L), wherein the at least one Turbomachine (H) is a turbomachine (H) according to one of the preceding claims. A method for generating a cooling air flow, the method comprising exciting a plate (3) of a Chladni resonator (3, 9). A method according to claim 14, wherein a movement of the excited plate (3) of the Chladni resonator (3, 9) by means of a Übertragerelements (4a, 5a, 6a) on a Vibration unit (7a) is transmitted, wherein the moving vibration unit (7a) generates the cooling air flow.