CN102543915A

CN102543915A - Cooling device

Info

Publication number: CN102543915A
Application number: CN201210025656XA
Authority: CN
Inventors: 和田宽昭; 神谷岳
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2007-09-14
Filing date: 2008-09-09
Publication date: 2012-07-04
Also published as: TW200930899A; JP5083322B2; US20120134858A1; CN101803011A; US20110064594A1; WO2009034956A1; JPWO2009034956A1; CN101803011B

Abstract

The invention provides a cooling device. A piezoelectric fan includes a blade that is joined to a piezoelectric oscillator that bends in response to an application of a voltage, and the blade of the piezoelectric fan is arranged to swing in a space between neighboring heat dissipating fins of a heat sink. The formation of a hole in the blade increases the amplitude of the blade and also improves the sweep effect of sweeping high-temperature air in the vicinity of the wall of the heat dissipating fin, and thus, improves the cooling capability of the piezoelectric fan.

Description

Cooling device

The application is that international filing date is that September 9, international application no in 2008 are that PCT/JP2008/066201, the application number that gets into the China national stage are 200880107653.2, name is called the dividing an application of application for a patent for invention of " cooling device ".

Technical field

The present invention relates to be used for the cooling device of use piezoelectric fan that the heat of electronic equipment internal is discharged towards electronic device exterior.

Background technology

In recent years, portable electric appts particularly, along with the progress of the high-density installationization of miniaturization and member, the hot countermeasure of electronic equipment internal has become problem.

As an example of the portable electric appts of aforementioned problems particular importance, can lift portable personal computer is example.In the portable personal computer, be devoted to the technological development of miniaturization, meanwhile, the high speed of CPU that is used to improve information processing capability is also in progress.Therefore, the high-density installation of member causes the air permeability straight line decline of electronic equipment internal, because of the caloric value increase of CPU, so the temperature rising that this heat is discharged to suppress electronic equipment internal towards electronic device exterior is difficult increasingly.

Before; Following radiator is disclosed in patent documentation 1; That is: and the heat generating part of heater radiator in succession have air tank to contain the operation strip of structure vacating to be situated between between many fin that required interval is arranged side by side; Rotation or swing this operation strip sending into cold air towards between fin, and discharge the heating installation between fin.

On the other hand, in patent documentation 2, disclose and have the air-out oscillator that contains piezoelectric vibrator, exhaust outlet and air entry are located at the piezoelectric fan that constitutes with one side.In this piezoelectric fan, be provided with a pair of dividing plate that prolongs to the inside from the peristome of case body with the mode of the both sides of clamping the air-out oscillator, the opening between the both sides of this each dividing plate and case body forms air entry, and the opening between two dividing plates forms exhaust outlet.

Here, the structure to the piezoelectric fan of patent documentation 2 describes based on Fig. 1.Among Fig. 1, piezoelectric fan 1 is the built-in fan body 5 that is made up of piezoelectric vibrator 3 and air-out oscillator 4 in the fan case 2 that forms flat partially case shape, at the same one side formation air entry 6 (6A, 6B) and the exhaust outlet 7 of fan case 2.Fan case 2 is made up of case body 8 peaceful tabular lids 9, and case body 8 has bottom surface sections 8a, the facial 8b in the left and right sides, 8c and the 8d of back side portion, and forms with the open mode of front face, and tabular lid 9 air-tightness are fixed in the upper surface of this case body 8.

Patent documentation 1: real the opening of Japan Patent put down the 02-127796 communique

Patent documentation 2: Japanese Patent Laid is opened the 2002-339900 communique

Disclosure of an invention

Invent technical problem to be solved

But in the aforementioned portable electric appts, if directly use the radiator like patent documentation 1, then the viewpoint from miniaturization is unsuitable.Therefore, consider to replace the operation strip of this patent documentation 1, and use the piezoelectric fan shown in patent documentation 2.

When using piezoelectric fan, though its air-out ability depends on the addendum modification of the piezoelectric vibrator in the air-out oscillator, the addendum modification of piezoelectric vibrator and not as the actuating quantity of the operation strip of patent documentation 1 big.

Therefore, be necessary to consider to carry out expeditiously the cooling of electronic equipment internal as far as possible.Record and narrate in the patent documentation 2, the interval between two dividing plates is aim to dwindle two dividing plates as far as possible with the gap that goes out aerofoil promptly basically as far as possible near the width that goes out aerofoil.

In order to the operation strip that the heating installation between the fin of the radiator of patent documentation 1 is discharged; Even be the member that exists air drag with respect to the operation strip action also can use the powerful drive source like motor to be rotated or to swing; So the action of operation strip can't be hindered because of the influence of air drag; But under the situation of the air-out oscillator of the piezoelectric fan that is used for patent documentation 2; Interval as if between the fin that is equivalent to two dividing plates is approaching with the width that goes out aerofoil, then will hinder displacement because of the air drag that action produced of air-out oscillator.

Here, according to the inventor of this case test gained go out aerofoil (to call " blade " in the following text) amplitude of front end and the relation of air drag as shown in Figure 2.The piezoelectric vibrator that draws this result is of a size of 6mm * 12mm, and blade is of a size of 6mm * 18mm * 40 μ m, and both are engaged with each other with short side part.

Because of considering that air drag and atmospheric density are proportional basically, atmospheric density and air pressure are proportional, so the amplitude of air pressure and blade front end is investigated and carried out when this experiment is driven by piezoelectric vibrator by the blade under the regulation reduced pressure atmosphere.As shown in Figure 2, the amplitude of blade receives air pressure, i.e. the influence of air drag, and air drag large amplitude more is more little.

So,, also will hinder displacement, thereby have the problem of the amplitude that is difficult to increase blade on the contrary because of the air drag that action produced of blade even make the interval between the fin that is equivalent to two dividing plates approaching as far as possible with the width of blade.

Therefore, the object of the present invention is to provide a kind of cooling device, its amplitude that can increase blade to be to improve draft capacity, in addition, improves from the radiating effect of fin so that cooling capacity promotes.

The technical scheme that the technical solution problem is adopted

Because of heating installation to be discharged is resulting by the heating heated air of fin, so the Temperature Distribution in the space between fin and heterogeneity, high-temperature part concentrates near the wall of fin.

In addition, the velocity flow profile when considering air flow between fin is though the flow velocity of the central portion air between fin is fast, because of there is the viscous drag of air in the wall with respect to fin, so slow more near the wall flow velocity of fin more.

That is, if only merely in fin chien shih air flow, be discharged from though then be present in the relatively low air of the temperature of the central portion between fin, the heating installation that is present near the high temperature the wall of fin is not by abundant discharge.

Inventors of the present invention find from various experiments and simulation; No matter whether the air between fin is all discharged by blade; If the mode by with near the heating installation the cleaning fin wall makes the blade action; The central portion of heating installation between fin moved,, then can fully efficiently the heat of electronic equipment internal be discharged to electronic device exterior so that heating installation is easy to discharge.

Therefore, the present invention's formation that is described below.

(1) apply and the piezoelectric fan of crooked piezoelectric vibrator and the blade that is adhered to or is integrally formed at this piezoelectric vibrator and swing by aforementioned piezoelectric vibrator by comprising, constitute with the radiator that comprises at least 2 fin according to voltage,

Aforementioned blade shaped becomes the strip that extends from aforementioned piezoelectric vibrator, and at the aforementioned piezoelectric vibrator of position configuration and the aforementioned blade that are not connected to the swing of aforementioned fin and the space between adjacent fin,

Aforementioned blade is provided with peristome or notch part.

By this structure,, increase the amplitude of blade because of peristome or notch part reduce air drag.Even the air output of the integral body that peristome or notch part caused reduces, near the cleaning effect of the heating installation the wall of fin also can not reduce, and follows the increase of amplitude also will improve whole cooling capacity.In addition, peel off as the central portion direction wave because of near the current of warm air the wall of fin and to flow, near the heating installation prioritized sweeping the fin, so radiating effect will improve, cooling capacity will promote.

(2) near aforementioned blade away from also being provided with counterweight the leading section of aforementioned piezoelectric vibrator side or the front end.

By this structure, because of making moment of inertia, counterweight increases, drive with the resonance frequency of the blade that comprises counterweight, the amplitude of blade will increase by this.Therefore, cooling capacity will improve.

(3) aforementioned blade can also form bending shape with the mode that aforementioned rectangular length direction shortens.

By this structure, the total length of blade will increase, and amplitude will increase.Therefore, cooling capacity will improve.

(4) can also be that aforementioned piezoelectric vibrator disposes with the mode that the end of aforementioned blade is clamped from the two sides, aforementioned piezoelectric vibrator and aforementioned blade constitute bimorph type oscillator.

By this formation, and apply the corresponding bending deflection amount of voltage and will increase, the amplitude of blade will increase.Therefore, cooling capacity will further improve.

(5) also can be arranged between the sidewall of this fin the fan that produces air-flow in air-flow direction for aforementioned fin.

By this structure, the heating installation that makes near the wall of fin current of warm air peel off, flow as the central portion direction wave because of the existence of peristome or notch part flows out by the fan high efficiency that other establishes, and whole cooling capacity will improve.

(6) aforementioned peristome is microscler shape along the length direction of aforementioned blade, and the size on the limit of parallel aforementioned peristome is bigger than the gap size between aforementioned fin and the aforementioned blade from this limit of Bian Zhiyu of the length direction of aforementioned blade.

Thus, can obtain higher cooling capacity.

The invention effect

According to the present invention, the amplitude of blade will increase, and cooling capacity will improve.In addition, meanwhile the radiating effect from fin will improve, and cooling capacity will promote.

Description of drawings

Fig. 1 is the figure of the piezoelectric fan structure of expression patent documentation 1.

Fig. 2 is the air drag of expression piezoelectric fan and the figure of amplitude relation.

Fig. 3 is the stereogram of the employed piezoelectric fan of cooling device of the 1st example.

Fig. 4 is the figure of the structure of the same cooling device of expression.

Fig. 5 is the figure of effect of peristome of the employed piezoelectric fan of cooling device of expression the 1st example.

Fig. 6 is the figure of appearance of the air-flow that swing produced of expression blade.

Fig. 7 is the figure that flows in the example that the gas flow temperature in the space between fin distributes when having or not the peristome that is formed at blade.

Fig. 8 is the stereogram of the employed piezoelectric fan of cooling device of the 2nd example.

Fig. 9 is the stereogram of the employed piezoelectric fan of cooling device of the 3rd example.

Figure 10 is the figure of effect of counterweight and the peristome of the same piezoelectric fan of expression.

Figure 11 is the stereogram of the employed piezoelectric fan of cooling device of the 4th example.

Figure 12 is the end view of the employed piezoelectric fan of cooling device of the 5th example.

Figure 13 is the stereogram of the employed piezoelectric fan of cooling device of the 6th example.

Figure 14 is the figure of the beam mode of the same piezoelectric fan of expression.

Figure 15 is the stereogram of the employed piezoelectric fan of cooling device of the 7th example.

Figure 16 is the beam mode of the same piezoelectric fan of expression and the figure of blade oscillating.

Figure 17 is the figure of structure of the cooling device of expression the 8th example.

Figure 18 is the figure of structure of the cooling device of expression the 9th example.

Figure 19 is the vertical view of the employed piezoelectric fan of cooling device of the 10th example.

Figure 20 is the figure of the position relation of expression fin, piezoelectric fan and the peristome that is formed at blade.

Figure 21 be expression when having or not piezoelectric fan with figure apart from the gradient difference of the corresponding temperature of distance of fin.

(symbol description)

19 metallic plates

20,25,26,27 piezoelectric vibrators

20a, 20b piezoelectric element

21 blades

22 peristomes

23 notch parts

24 counterweights

28,29 pads

30 fin

31～39 piezoelectric fans

40 radiators

41 supporting members

50 Air Blast fans

100,101 cooling devices

110 heaters

120 circuit substrates

Embodiment

" the 1st example "

Fig. 3 is the stereogram of the employed piezoelectric fan of cooling device of the 1st example.Piezoelectric fan 31 among Fig. 3 is made up of blade with peristome 22 21 and piezoelectric vibrator 20.Piezoelectric vibrator 20 is the piezoelectric vibrators in the bimorph type that constitutes as the two sides configuration piezoelectric element of the metallic plate of target.Promptly; Piezoelectric element as the both sides of the metallic plate of the target of this piezoelectric vibrator 20 forms electrode film on surface separately; Between these electrodes and the metallic plate, polarize by the driving voltage of the polarised direction that applies corresponding piezoelectric element and to handle with crooked to carry out flexural vibrations in length direction (L1 dimensional directions) as target.

Blade 21 is to connect the member that forms rectangular-shaped peristome 22 with respect to corrosion resistant plate, and its end is adhered to the end of piezoelectric vibrator 20.

Each size of piezoelectric fan 31 shown in Figure 3 is described below.

L1：12mm

L2：18mm

W：6mm

t：50μm

In addition, peristome 22 is of a size of 12mm * 2mm, and its end near root coincides with the end of piezoelectric vibrator 20.

Fig. 4 (A) is that piezoelectric fan 31 shown in Figure 3 is disposed at the assigned position of radiator and main stereogram of the cooling device that constitutes.In the radiator, a plurality of fin 30 as shown in Figure 4 are parallel outstanding, and the mode that 30 of adjacent fin are swung so that the blade 21 of piezoelectric fan 31 is not connected to fin 30 disposes piezoelectric fan 31.

Fig. 4 (B) is the whole front view of the being seen cooling device of the bearing of trend (direction relative with air supply direction) from fin.

Radiator 40 comprises a plurality of fin 30 that extend parallel to each other.Heaters (generating component) 110 such as CPU, the bottom surface that disposes radiator 40 at this upper surface of 110 with the mode of hot combination are installed in top at circuit substrate 120 in this example.

So constitute cooling device 100 by radiator 40 and a plurality of piezoelectric fans 31.

The amplitude variations that has or not the blade front end that is produced of the fin 30 that has that it's too late of the peristome 22 that the blade 21 of Fig. 5 presentation graphs 3, piezoelectric fan 31 shown in Figure 4 is set.

So if exist fin then will reduce in the both sides of blade with amplitude as the contrast blade front end of open space.For example the situation to input voltage 30V and imperforation portion compares, and is 9.2mm with respect to the amplitude of finless situation lower blade front end, and the amplitude of blade front end is reduced to 5.5mm when having fin.But, can make the amplitude of blade front end increase to 7.5mm by peristome 22 is set.

This is because by the existence of peristome 22, the substantive area of oscillating vane 21 is cut down, and improves the corresponding minimizing of air drag like the said ventilation via peristome 22 in back in addition.

By so establishing peristome 22 at blade, though can know can also be bigger in the space between fin the amplitude fluctuation blade.

Fig. 6 is the figure of effect that the peristome 22 of blade 21 is located in expression.Piezoelectric fan 31 is that the center makes blade 21 in the arrow u shown in the figure, the swing of d direction with the support (left end among the figure) of piezoelectric vibrator 20.By this, the air-flow that becomes shown in arrow A F of the air in the space between the fin 30 flows.At this moment, also produce from the top downwards, reach the air-flow that passes peristome 22 from the lower direction top, mix with the air-flow of upper surface side that flows in blade 21 and lower face side.In addition, meanwhile, near the current of warm air the wall of fin 30 is peeled off at the side edge of blade, and this heating installation is to the direction of peristome 22, and promptly the central portion direction in the space between 2 adjacent fin 30 flows.

So peristome 22 is not only to reduce air drag to increase the amplitude of blade 21; Also function as follows; That is: peel off near the wall of fin 30 current of warm air, and all air-flows in the space of this current of warm air between 2 adjacent fin 30 are cleared away to the outside.(below, this action effect is called " cleaning effect ") therefore can improve radiating effect.

Fig. 7 is the figure that is used to explain the effect of the piezoelectric fan that comprises the blade that is provided with peristome.The low part of brightness is a low-temperature region among Fig. 7, and the high part of brightness is a high-temperature area.

For though the Temperature Distribution that flows in the air-flow in the space between fin in the cooling device of trying to achieve structure shown in Figure 4 is necessary to carry out 3 dimension simulations, huge because of amount of calculation, replace with 2 dimension simulations here.

Fig. 7 (A) expression makes adjacent 2

fin

30,30 rise to regulation high temperature, and in this fin 30 space each other, the Temperature Distribution when direction flows the cold wind of set point of temperature from left to right in figure.

If like this airflow flowing laminar flow in fin 30 space each other, then the central portion flow velocity the closer to the space is big more, the wall place of fin 30 because of the viscous drag of air in theory flow velocity be 0.Therefore the cold wind that flows into from left end is still cold wind through the central portion in fin 30 space each other, and to flow to the amount of right-hand member direction more, and the radiating effect of fin 30 is low.

Fig. 7 (B) expression is near the oar P of the wall of fin 30 Temperature Distribution during the left and right directions vibration in figure.Other condition is identical with the situation of (A).This oar P is equivalent to the position of the both sides of blade shown in Figure 4 21 split shed portions 22.

The heating installation (high temperature air layer) that so is distributed in the wall of fin 30 flows as the central portion wave in space and is cleared away along with flowing through the air-flow in the whole space.Therefore can improve whole radiating effect.

" the 2nd example "

Blade 21 is formed with the single peristome 22 that extends in the length direction of blade in the 1st example, and Fig. 8 representes the piezoelectric fan of 2 kinds of different with it structures.

In the example of Fig. 8 (A), the leading section (away from piezoelectric vibrator 20 sides) that is illustrated in blade 21 is formed with the piezoelectric fan 32 of the notch part 23 that extends in the length direction of blade 21.In the structure shown in this Fig. 8 (A), the position configuration of the oral area of can also explaining clearly is in the leading section of blade 21.Even so the leading section at blade 21 forms notch part 23, and the amplitude that also can obtain blade 21 through the minimizing of air drag increases the cleaning effect of the high temperature air of effect and fin wall.

In the example of Fig. 8 (B), the blade 21 that is formed with a plurality of peristome 22a～22d is engaged in piezoelectric vibrator 20 and constitutes piezoelectric fan 33.

The position of the peristome on above-mentioned blade 21 and the action effect difference that quantity produced are described below.

At first; As shown in Figure 3, when peristome 22 is formed near the root (piezoelectric vibrator 20 sides) of blade, the little place of displacement when being present in the swing of blade 21 because of peristome 22; So the minimizing effect of air drag is little; It is little that the amplitude of blade 21 increases effect, but the extrusion effect of the air of blade 21 leading sections is not because of the peristome loss, so air-supply property is high.

On the other hand, if as as Fig. 8 (A) notch part 23 be formed at (or peristome is formed near the leading section) near the leading section of blade 21, the then minimizing effect height of air drag and the amplitude increase of blade 21.Therefore the cleaning effect of the high temperature air of fin wall increases.But because of the extrusion effect that extrudes air-flow from the blade leading section descends, so the decline of air-supply property.

Because of air-supply property as so be a trade-off relation with the cleaning effect in a way, so confirm shape, position, big or small the getting final product of peristome to obtain the mode of high cooling capacity.

In addition, when a plurality of peristome being set as Fig. 8 (B), the size of these peristomes, form position, quantity etc. also consider that aforementioned air-supply property and cleaning effect confirm to get final product.

In addition; When peristome is formed near the root (piezoelectric vibrator 20 sides) of blade; Though the substantive width of the position that the bending stress of blade 21 is relatively large diminishes; But, peristome 22, can relax concentrating of bending stress, the reliability when guaranteeing to drive for a long time in the shape that length direction extends by being formed not in the cross direction of blade 21.

" the 3rd example "

Fig. 9 is the stereogram of the employed piezoelectric fan of cooling device of the 3rd example.In this example, by forming peristome 22, leading section comprises that the blade 21 of

counterweight

24a, 24b and piezoelectric vibrator 20 constitute piezoelectric fan 34.

Counterweight

24a, 24b and blade 21 are identical to be constituted by stainless steel, engages by bonding agent.Size L3 is 2mm among the figure of this

counterweight

24a, 24b, and d is 0.5mm.In addition, the gauge of blade 21 is 100 μ m.Other size L1, L2, W are all L1=12mm, L2=18mm, W=6mm mutually with the situation of the 1st example shown in Figure 3.The formation position and the size of peristome 22 are identical with situation shown in Figure 3.

Figure 10 is the figure of effect of counterweight and the peristome of the expression cooling device that comprises piezoelectric fan shown in Figure 9 34.Can know that so by comprising

counterweight

24a, 24b and peristome 22, the piezoelectric fan that all is not provided with compared with counterweight and peristome can obtain bigger amplitude in the situation of open space internal vibration.When for example applying input voltage 30V; Under the situation of the piezoelectric fan that counterweight and peristome all are not provided with, the about 5.5mm of the amplitude of blade front end is relative therewith; Shown in figure 10 under the situation of the piezoelectric fan that comprises counterweight and peristome, the amplitude of blade front end increases to 9.5mm.

So

counterweight

24a, 24b are installed by leading section at blade 21; Because of making moment of inertia, counterweight increases; Resonance frequency by with the blade that comprises counterweight drives, even also can increase the amplitude of blade 21 in the space between fin as shown in Figure 4 during the above-mentioned piezoelectric fan 34 of configuration.So can improve cooling capacity.

In addition, there is the effect that multiplies each other in the formation of the additional and peristome of counterweight.This is because the additional formation with peristome of counterweight is moved the blade center of gravity forward end, the moment of inertia increase of the every quality of blade.

Therefore, be accompanied by

counterweight

24a, 24b the amplitude of blade is increased, the cleaning effect that peristome 22 is produced can further improve.

" the 4th example "

Figure 11 is the stereogram of the piezoelectric fan of the 4th example.In this example, constitute piezoelectric fan 35 by blade 21 and with the piezoelectric vibrator 20 of it joint, blade 21 is provided with

peristome

22b, 22c, and integral body is strip, and so that the mode bending that length direction shortens.By structure like this, the total length of blade 21 increases, by drive vane 21 so that its with fundamental resonance, amplitude increases, cooling capacity improves.In addition, although blade 21 total lengths are long because of can the lengthwise dimension globality being shortened, so can suppress the whole maximization of cooling device and improve cooling capacity.

In addition, blade 21 is being divided into the mode bending at 3 positions shown in 21a, 21b, the 21c in this example, and near the position 21a piezoelectric vibrator 20 do not form peristome, and 21b,

21c form peristome

22b, 22c respectively at the position.In addition,

peristome

22b, 22c avoid dogleg section and form.By structure like this, the elastic reinforcement of the root of piezoelectric vibrator side, the elasticity of leading section weakens, and the amplitude of

position

21b, 21c (the particularly amplitude of 21c) increases.Therefore, carry out swinging as the circular fan motion, can obtain high draft capacity.

In addition, stress does not concentrate on peristome, so the reliability can guarantee to drive for a long time the time.

In addition, local in the leading section or the regulation of the blade of above-mentioned bending structure, also can install counterweight as shown in Figure 9.

" the 5th example "

Figure 12 is the end view of the piezoelectric fan of the 5th example.Each example so far is the type that engages piezoelectric vibrator 20 in the one side of blade 21; But piezoelectric fan 36 shown in Figure 12; Be to dispose

piezoelectric element

20a, 20b respectively, constitute bimorph type oscillator by

piezoelectric element

20a, 20b and blade 21 with the mode that the end of blade 21 is clamped from the two sides.

Form electrode film on

piezoelectric element

20a, 20b surface separately; Between these electrodes and the blade 21; Driving voltage by applying corresponding to the polarised direction of

piezoelectric element

20a, 20b makes

piezoelectric element

20a, 20b flexible round about, drives as bimorph type piezoelectric vibrator.

By becoming so bimorph type,, can increase the amplitude of blade 21 more efficiently because of

piezoelectric element

20a, 20b can increase blade 21 with respect to the bending deflection amount that applies voltage.

Though expression peristome 22 is formed at the example of the piezoelectric fan of blade 21 among Figure 12, for as Fig. 9 at the leading section of blade 21 structure of counterweight is installed, or also suitable equally like the piezoelectric fan of the structure that makes blade 21 bendings of Figure 11.

" the 6th example "

Figure 13 is the stereogram of the employed piezoelectric fan of cooling device of the 6th example.As shown in the drawing 2 piezoelectric vibrator 26a, a 26b end is separately engaged via pad 28 each other constitutes U font piezoelectric vibrator unit, and the end of a side piezoelectric vibrator 26a engages with blade 21 via pad 29 and constitutes piezoelectric fan 37.On blade 21, form peristome 22 in this example.

In addition,

aforementioned pad

28,29 is not to be necessary.

Beam mode when Figure 14 representes that the voltage of aforementioned U font piezoelectric vibrator unit applies.Figure 14 (A) is that the voltage that applies to 2

piezoelectric vibrator

26a, 26b is 0 o'clock state, (B) is the state when applying positive voltage, (C) is the state when applying negative voltage.

Front end because of the piezoelectric vibrator 26b of downside is fixed here, thus the front end of the piezoelectric vibrator 26a of upside and the contrast of using single piezoelectric vibrator, with about 2 times angle swinging.Therefore, can further increase the amplitude of blade shown in Figure 13 21.

In addition, though the piezoelectric fan that is formed at blade 21 with peristome 22 in the example of Figure 13 is that illustration goes out, for as Fig. 9 at the leading section of blade 21 structure of counterweight is installed, or as the piezoelectric fan of the structure that makes blade 21 bendings of Figure 11 also suitable equally.

" the 7th example "

Figure 15 is the stereogram of the employed piezoelectric fan of cooling device of the 7th example.As shown in the drawing with respect to comprising that 3

piezoelectric vibrator

27a, 27b, 27c part and the integral body piezoelectric vibrator unit for the E font constitutes piezoelectric fans 38 via pad 29 engagement blade 21.This example split shed portion 22 is formed at blade 21.

The beam mode of the piezoelectric vibrator cell mesh of the aforementioned E font of (A)～(C) expression of Figure 16.In addition, the swing of the blade of the aforementioned piezoelectric fan 38 of Figure 16 (D)～(F) expression.

Figure 16 (A) is that the voltage that applies to

piezoelectric vibrator

27a, 27b, 27c is 0 o'clock state, (B) is the state when applying positive voltage, (C) is the state when applying negative voltage.

Front end because of

piezoelectric vibrator

27a, 27b is fixed here, so the front end of the piezoelectric vibrator 27c of central authorities and the contrast of using single piezoelectric vibrator are with about 2 times angle swinging.Therefore, can further increase the amplitude of blade shown in Figure 15 21.

In addition, though the piezoelectric fan that is formed at blade 21 with peristome 22 in the example of Figure 15 is that illustration goes out, this moment for as Fig. 9 at the leading section of blade 21 structure of counterweight is installed, or also suitable equally like the piezoelectric fan of the structure that makes blade 21 bendings of Figure 11.

" the 8th example "

Figure 17 is the figure of structure of the cooling device of expression the 8th example.This cooling device 101 is made up of piezoelectric fan 31, radiator 40 and Air Blast fan 50.In the 1st example～the 8th example; Basically constitute cooling device by piezoelectric fan and radiator; And the mode that piezoelectric fan is dispelled the heat by the air in the space that fin was surrounded of radiator with cleaning constitutes; But in this example shown in Figure 17, the air in the fin 30 formed spaces of radiator 40 is stirred by piezoelectric fan 31, makes it whole by Air Blast fan 50 and blows to the outside.

Piezoelectric fan 31 is made up of blade that is formed with peristome 22 21 and piezoelectric vibrator 20, and is basic identical with situation shown in Figure 3.But, blade 21 towards being that length direction with respect to fin 30 is with about 45 ℃ of inclinations in this example.The support of piezoelectric vibrator 20 (fixed part) can be located at the outside of radiator 40 thus, and the installation of piezoelectric fan 31 is easy to carry out.

In addition, the composition that peristome 22 is relative with the air-flow that Air Blast fan 50 is produced increases, and can more approach the simulated conditions shown in Fig. 7 (B), improves the cleaning effect of the high temperature air of fin 30 walls.

In addition, though the piezoelectric fan that is formed at blade 21 with peristome 22 in the example of Figure 17 is that illustration goes out, for as Fig. 9 at the leading section of blade 21 structure of counterweight is installed, or as the piezoelectric fan of the structure that makes blade 21 bendings of Figure 11 also suitable equally.

" the 9th example "

Figure 18 (A) is the stereogram of structure of the cooling device of expression the 9th example, and Figure 18 (B) is the vertical view of this piezoelectric fan.

Shown in Figure 18 (B), piezoelectric fan 39 comprises the outstanding metallic plate 19 that root is a plurality of blades 21 of one that is formed with.Each blade 21 is formed with peristome 22.On the metallic plate 19, piezoelectric vibrator 25 is affixed on the root of blade 21.Metallic plate 19 is installed on supporting member 41 by screw 42.By piezoelectric vibrator 25 is applied alternating voltage, making metallic plate 19 and blade 21 is that fulcrum is swung with the position of supporting member 41.

Shown in Figure 18 (A), cooling device 102 constitutes by aforementioned piezoelectric fan 39 being disposed at bottom surface specified altitude apart from radiator 40 (central authorities' height or than it lower slightly height).Comprise parallel a plurality of fin 30 in the radiator 40, be not connected to fin 30 with the blade 21 of piezoelectric fan 39 between the adjacent fin 30 and the mode of swing disposes piezoelectric fan 39.

So, formation comprises the cooling device 102 of swinging the piezoelectric fan of a plurality of blades with single piezoelectric vibrator.

" the 10th example "

Figure 19 is the vertical view of the piezoelectric fan of the 10th example.

In the example of Figure 19 (A), metallic plate 19 is divided into the area L in left side, the zone C of central authorities, these 3 zones of region R on right side, piezoelectric vibrator 25L, 25C, 25R are located at each zone respectively.Can independently swing these 3 zones by this.

Equally, in the example of Figure 19 (B), metallic plate 19 is divided into the area L in left side and these 2 zones of region R on right side, piezoelectric vibrator 25L, 25R are located at each zone respectively.Can independently swing these 2 zones by this.

By this structure, can swing each regional blade 21 according to purpose.For example, under the situation of Figure 19 (A),,, supporting member 41 suffered reaction forces are reduced with anti-phase driven piezoelectric vibrator 25C by with positive driven piezoelectric vibrator 25L, 25R.Equally, under the situation of Figure 19 (B),,, supporting member 41 suffered reaction forces are reduced with anti-phase driven piezoelectric vibrator 25R by with positive driven piezoelectric vibrator 25L.

So, can suppress to be equipped with the vibration of the member of this supporting member 41, reach quietization.

In addition, regional cutting apart counted or each regional interior blade quantity is not limited to situation shown in Figure 19, and metallic plate 19 and blade 21 are got final product with suitable setting as the vibration mode vibration of expection.

" fin, piezoelectric fan and be formed at the position relation of the peristome of blade "

For position relation, the size relationship of each one of the cooling device shown in aforementioned each example, inquire into here.

Between the fin of radiator, to insert blade, blade is scraped the hot-air of getting and clear away fin surface and is promoted cooling as prerequisite as the piezoelectric fan of object.Be to promote cooling, increase and scrape that to get area extremely important.Therefore, be necessary to increase radiator fin surface area and the amplitude of blade is increased, vertically long blade should be set in adjacent fin gap to each other.

Figure 20 is the vertical view of the state of configuration blade 21 in fin 30 gap to each other of radiator.The x direction is called vertically here, and the y direction is called Width, and the z direction is called thickness direction.

Because of desiring to scrape the hot-air of getting

fin

30,30 surfaces, so fin 30 is more little good more with the spacing G of blade 21 by blade 21.But if dwindle spacing G, then the air drag during oscillating vane 21 will increase, and the amplitude of blade 21 will dwindle.On the other hand, consider to scrape the air this purpose on fin 30 surfaces of getting radiator, the air of scraping the central portion (approximate with the zone shown in the symbol B among Figure 20) of getting 30 of fin is not important.Therefore, establish peristome 22 for the minimizing air drag at the central portion of blade 21 its reasonability is arranged.

If a purpose that peristome 22 is established in emphasis then can spread all over the total length of blade 21 and establish peristome 22.But according to following reason, reality is established peristome at the central portion (place shown in the symbol A among Figure 20) of blade 21 only.At first consider the root portion of blade 21, less because of the amplitude of root, air drag is also little, so there is not necessity that peristome is set.Next considers the fore-end of blade 21, and undoubtedly because of not having blade 21 than the more preceding place of front end, the air that therefore extrudes can be dissipated to the broad space simply.Therefore, the leading section office of blade 21, the minimizing effect of the air drag that peristome produced is smaller.In addition, if till the front end of blade 21, form peristome, then become not only thin but also 2 elongated blades are swung between narrow fin.Though air drag reduces, exist the action of each blade to influence each other via air, can't form the situation of stable vibration.Therefore, the fore-end of blade 21 is suitably firm connection.In addition, do not put aside for 30 heats of fin that make radiator, air-supply effect to a certain degree is necessary.The maximum fore-end of amplitude is big to the influence of air-supply effect, if more connecting out peristome near a side of root than front end, then is easy to form the flowing of stable air of a direction.

Consider and only to establish peristome 22 from above-mentioned these situation at the central portion of blade 21.

Shape about peristome 22; Based on the reason that is described below; In the vertical can except that root and the fore-end on a large scale in offer peristome; Relative therewith, be necessary on the Width to guarantee from the size E on limit to the limit of the peristome that is parallel to this limit 22 of the length direction of blade 21 for more than to a certain degree.From this situation, and blade 21 is vertically can knows that than length the shape of peristome 22 is also longer for vertically originally.

Longitudinal size about peristome:

If ignore the end face effect, then the air drag of a certain position of x direction can be thought of as, and is proportional with the quadratic sum sectional area ratio of speed.That is, if amplitude is that h (x), frequency are that f, sectional area ratio are r _A, then,

The air drag ∝ f at x place ²h ²r _A

The air drag in each cross section spreads all over the value air drag as a whole that blade progress row integration obtains.

In addition, [sectional area ratio]=([blade is wide]-[peristome is wide])/[fin interval to each other].So, square proportional because of air drag and amplitude is so near the air drag the little root of amplitude can be ignored.Therefore, it is meaningless basically near root, to establish peristome.

About leading section, even imperforation portion, also there is large space in the more preceding place of its front end.Therefore, though the air of extrusion the narrow gap (the G part among Figure 20) through blade 21 and fin but also the forward end direction flow.Therefore, air drag is littler than the valuation of ignoring aforesaid end face effect.The scope of this end face effect is equal to the width of blade 21 in theory basically.Therefore, at least from front end to the scope of the wide equal length of blade in, even also do not have necessity of offering peristome from the viewpoint of air drag.

Width size about peristome:

Figure 21 is when having or not piezoelectric fan, with the figure apart from the gradient difference of the corresponding temperature of distance of fin.Thick line is the situation that does not have piezoelectric fan, and fine rule is the situation that has piezoelectric fan.Temperature Distribution between the fin of radiator is shown in the thick line of Figure 21.Piezoelectric fan exists and the situation of action, because of making the air mixed at blade two ends, so shown in fine rule in scheming, the temperature homogenization (temperature gradient is mild) of blade-section (part of symbol E among the figure).Its result, the temperature of the gap portion between fin and the blade (part of symbol G among the figure) descends, and the temperature gradient of fin surface is precipitous.Proportional because of heat stream and temperature gradient, so this expression is flowed out a large amount of heats from fin surface, promptly cooling effect promotes.

Because the mechanism that above-mentioned cooling capacity promotes, so, then can't fully promote cooling capacity if the temperature difference at blade two ends (position of the position of G and G+E among Figure 20) is insufficient.Therefore, undoubtedly G must be set in the big zone of variations in temperature (both sides that are blade 21 should be as far as possible near fin 30), also is necessary to guarantee to form the size of abundant two ends temperature difference for size E.

If quite near apart from the distance of fin 30, then Temperature Distribution roughly becomes straight line.If with the gradient (=temperature gradient) of this straight line be k, the temperature of fin surface is To, is that the temperature of the position of size G is To+k*G apart from the wall of fin then, and distance is that the temperature of the position of (G+E) is To+k* (G+E).During because of the position temperature complete and homogeneous of blade 21, the temperature of the position of this blade 21 is To+k* (G+E/2), so but the temperature gradient valuation is k* (1+0.5*E/G).

That is, if E=G then estimates to promote maximum 50% cooling capacity.Consider the Temperature Distribution complete and homogeneousization that can't make blade part, Temperature Distribution also might break away from the situation of linear domain, promotes for obtaining clear and definite cooling capacity, confirms that E＞G can be effective.

" other example "

More than shown in several kinds of examples in, the end of bonding blade constitutes the piezoelectric fan of single piezoelectric chip type in the end of piezoelectric vibrator, but the end of blade also can bonding piezoelectric vibrator whole.

In addition, more than shown in several kinds of examples in, represented the example of the bonding counterweight in end of blade, but counterweight and blade integral forming also can.In addition, counterweight also can be located at the end of blade and be located near the end.

In addition, more than shown in each example in, blade also can use high metallic plate or the resin plate of elasticity such as phosphor bronze beyond the stainless steel.

In addition; In the example beyond the structure shown in Figure 12; Bimorph type piezoelectric vibrator is adhered to the one side of blade, but uses single piezoelectric element as the piezoelectric vibrator that is adhered to the one side of blade, constitutes single piezoelectric chip type oscillator by this piezoelectric element and blade and also can.

Claims

1. cooling device, it has: piezoelectric fan, this piezoelectric fan comprise according to voltage and applying and crooked piezoelectric vibrator and the blade that is adhered to or is integrally formed at this piezoelectric vibrator and swing by said piezoelectric vibrator; And radiator, this radiator comprises at least 2 fin, it is characterized in that,

Said blade shaped becomes the strip that extends from said piezoelectric vibrator, and said piezoelectric vibrator of position configuration and the said blade in the space of the said fin of butt ground between adjacent fin not, swung,

Said blade arrangement becomes the wall approximate vertical of blade surface (Width of blade) and said fin,

Said blade is provided with peristome or notch part.

2. cooling device as claimed in claim 1 is characterized in that, said blade away from being provided with counterweight near the leading section of said piezoelectric vibrator side or the front end.

3. according to claim 1 or claim 2 cooling device is characterized in that, said blade is so that the mode that length direction shortens forms bending shape.

4. cooling device as claimed in claim 1 is characterized in that, said piezoelectric vibrator disposes with the mode that the end of said blade is clamped from the two sides, and said piezoelectric vibrator and said blade constitute bimorph type oscillator.

5. cooling device as claimed in claim 2 is characterized in that, said piezoelectric vibrator disposes with the mode that the end of said blade is clamped from the two sides, and said piezoelectric vibrator and said blade constitute bimorph type oscillator.

6. cooling device as claimed in claim 3 is characterized in that, said piezoelectric vibrator disposes with the mode that the end of said blade is clamped from the two sides, and said piezoelectric vibrator and said blade constitute bimorph type oscillator.

7. cooling device as claimed in claim 1 is characterized in that, is provided with the fan of airflow flowing in the space that is created between said fin.

8. cooling device as claimed in claim 2 is characterized in that, is provided with the fan of airflow flowing in the space that is created between said fin.

9. cooling device as claimed in claim 3 is characterized in that, is provided with the fan of airflow flowing in the space that is created between said fin.

10. cooling device as claimed in claim 4 is characterized in that, is provided with the fan of airflow flowing in the space that is created between said fin.

11. cooling device as claimed in claim 5 is characterized in that, is provided with the fan of airflow flowing in the space that is created between said fin.

12. cooling device as claimed in claim 6 is characterized in that, is provided with the fan of airflow flowing in the space that is created between said fin.

13. like each described cooling device in the claim 1,2,4,5,7,8,10 and 11; It is characterized in that; Said peristome is a shape long on the length direction of said blade; The size on the limit of parallel said peristome is bigger than the gap size between said fin and the said blade from this limit of Bian Zhiyu of the length direction of said blade.

14. cooling device as claimed in claim 3; It is characterized in that; Said peristome is a shape long on the length direction of said blade; The size on the limit of parallel said peristome is bigger than the gap size between said fin and the said blade from this limit of Bian Zhiyu of the length direction of said blade.

15. cooling device as claimed in claim 6; It is characterized in that; Said peristome is a shape long on the length direction of said blade; The size on the limit of parallel said peristome is bigger than the gap size between said fin and the said blade from this limit of Bian Zhiyu of the length direction of said blade.

16. cooling device as claimed in claim 9; It is characterized in that; Said peristome is a shape long on the length direction of said blade; The size on the limit of parallel said peristome is bigger than the gap size between said fin and the said blade from this limit of Bian Zhiyu of the length direction of said blade.

17. cooling device as claimed in claim 12; It is characterized in that; Said peristome is a shape long on the length direction of said blade; The size on the limit of parallel said peristome is bigger than the gap size between said fin and the said blade from this limit of Bian Zhiyu of the length direction of said blade.