JP2002130199A - Piezoelectric fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently suck air for cooling, and to freely control an air flow inside of a mounted apparatus. SOLUTION: This piezoelectric fan is provided with a fan 2 for sandwiching the base end part side of an elastic plate 5 between a pair of piezoelectric elements 4 and installing a vibrating plate 6 on the other end part side of the elastic plate 5, and a case 3 for internally housing the fan 2 in a state capable of vibrating the vibrating plate 6 while supporting the base end part side of the elastic plate 5 as a cantilever. The case 3 has respectively opening parts 11a, 11b, 11c and 11d on a side surface opposed to a base end part of the elastic plate 5, a side surface opposed to a tip part of the vibrating plate 6, and a side surface opposed to at least one side end part of both side end parts orthogonal to the tip part of the vibrating plate 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric fan using a piezoelectric element, and more particularly to a piezoelectric fan suitable for cooling the inside of an electronic device such as a portable personal computer.

[0002]

2. Description of the Related Art For example, in an electronic device such as a portable personal computer having a central processing unit (CPU), a problem of cooling heat generated inside the device is serious due to an increase in power consumption due to an increase in the speed of the CPU. Is becoming

In general, a portable personal computer (hereinafter, referred to as a portable PC) is provided with a cooling fan inside the device to discharge heat inside the device to the outside.

More specifically, as shown in FIG. 12, a portable PC has a suction port 101 for sucking air for cooling into a side surface of a device body 100 and heat generated inside the device body 100. An outlet 103 for discharging the cooling fan 102 to the outside is provided.

In this portable PC, the device body 10
The air sucked from the suction port 101 of the
0 while absorbing heat generated from a heat source such as a microprocessor mounted inside the apparatus main body 100 while passing through the inside of the apparatus main body 100, the cooling fan 102 discharges the exhaust port 10.
3 to the outside of the device main body 100. Thereby, the inside of the device main body 100 can be cooled. It should be noted that, depending on the device, there is also a structure in which the above-described suction port 101 is not provided, and the clearance after assembly of the device body 100 is used as the suction port.

The arrows shown in FIG. 12 schematically show the flow of air generated in the apparatus main body 100.
13 to 17, the flow of air is schematically shown by arrows shown in the drawings.

As the cooling fan 102, an electromagnetic fan 200 as shown in FIG. 13 is generally used. The electromagnetic fan 200 has a structure in which a fan 202 driven by an electromagnetic motor is housed in a fan case 201 formed in a substantially box shape. The fan case 201 has a suction port 203 on its upper surface for sucking air, and a discharge port 20 on one side surface for discharging air sucked from the suction port 203.
4 are provided.

[0008] The electromagnetic fan 200 is a portable P
When the electronic device is used in an electronic device in which the thickness of the device main body 100 is limited as shown in FIG.
Is rotated in a plane parallel to the upper surface of the fan case 201, so that air is sucked from an inlet 203 provided on the upper surface, and the sucked air is
It will be discharged from the discharge port 204 provided on one side surface of the one.

However, in the above-described portable PC, as shown in FIG. 14, when such an electromagnetic fan 200 is used, inside the device main body 100, between the device main body 100 and the electromagnetic fan 200, Fan case 2
It is necessary to secure an upper space S for securing the flow of the air sucked through the suction port 203 formed on the upper surface of the upper surface S1. Therefore, the use of such an electromagnetic fan 200 in the above-described portable PC requires the device main body 10.
This was very disadvantageous in reducing the thickness of the zero.

Therefore, a piezoelectric fan 300 as shown in FIG. 15 has attracted attention as a cooling fan 102 capable of suppressing the dimension in the thickness direction.

The piezoelectric fan 300 includes a fan 304 in which a base end of an elastic plate 302 is sandwiched between a pair of piezoelectric elements 301 and a diaphragm 303 is attached to the other end of the elastic plate 302. And a pair of piezoelectric elements 301
The base end side of the elastic plate 302 sandwiched between the fixing plate 30
5 and a fan case 306 formed in a substantially box shape for accommodating a fan 304 therein while allowing the diaphragm 303 to vibrate while being fixed and cantilevered. Also,
In the fan case 306, a suction port 307 for sucking air, and a side face facing the suction port 307, that is, a diaphragm is provided on a side face (hereinafter, referred to as a front side face) facing the base end portion of the elastic plate 302. A discharge port 308 for discharging the air sucked from the suction port 307 is provided on a side surface (hereinafter, referred to as a rear side surface) opposite to the distal end of the 303. Note that the upper surface of the fan case 306 is sealed with a fan cover 309.

In the piezoelectric fan 300, the fan 304
By applying an AC voltage to the pair of piezoelectric elements 301, the diaphragm 303 vibrates via the elastic plate 302 sandwiched between the pair of piezoelectric elements 301. Then, when the diaphragm 303 vibrates inside the fan case 306, air is sucked from the suction port 307 provided on the front side surface of the fan case 306,
The air sucked from the suction port 307 is supplied to the fan case 3
06 from the outlet 308 provided on the rear side surface.

Therefore, in the portable PC described above, FIG.
As shown in FIG. 6 and FIG.
By using 0, between the device main body 100 and the piezoelectric fan 300 inside the device main body 100,
There is no need to secure the upper space S as in the above-described electromagnetic fan 200, and air can be sucked and discharged from the side of the fan case 306.
0 can be reduced in thickness.

[0014]

By the way, as the above-mentioned problem of cooling the portable PC, it has become increasingly important to control the flow of air inside the apparatus main body 100. That is, when the inside of the device main body 100 is cooled by the above-described piezoelectric fan 300, the flow of air generated inside the device main body 100 is predicted in advance, and the arrangement of each heat source, the amount of heat generated during operation, and the like are taken into consideration. while doing,
It is necessary to control this air flow.

However, as shown in FIG. 18, for example, in the above-described portable PC, each electronic component 104A, 104 serving as a heat source mounted inside the device main body 100 is provided.
Depending on the arrangement of B and 104C, it is very difficult to control the flow of air inside the device main body 100 by the above-described piezoelectric fan 300.

Here, in the portable PC shown in FIG.
The piezoelectric fan 300 has an outlet 308 and the device body 10.
0 is disposed so as to face the outlet 103 provided on one side surface. Also, the suction port 1 of the device body 100
Reference numeral 03 is provided on the side of the piezoelectric fan 300 facing the suction port 307.

The electronic component 104A (hereinafter referred to as a heat source A ')
That. ) Has the largest amount of heat generated during operation, and the electronic components 104B and 104C (hereinafter, referred to as heat sources B ′ and C ′).
Has a smaller heat value during operation than the heat source A ′. Among them, the heat source A ′ is the piezoelectric fan 300
Is thermally connected to the piezoelectric fan 300 by the heat pipe 105. The heat source B ′ is arranged near the suction port 101 of the device main body 100.
The heat source C ′ is connected to the inlet 101 and the outlet 1 of the main body 100.
It is arranged at one corner of the device main body 100, which is off the extension line connecting the device main body 03 with the main body.

In this case, since the heat source A ′ is arranged near the piezoelectric fan 300 inside the apparatus main body 100 and the heat source A ′ is connected to the piezoelectric fan 300 by the heat pipe 105, Cooling is most preferentially performed on the heat source A '. In addition, the heat source B ′ is also disposed near the suction port 101, so that appropriate cooling is performed. Therefore, this portable PC has a structure in which the temperature rise of these heat sources A ′ and B ′ is suppressed.

However, in this portable PC, when the heat source C ′ is directly hit by the air flow generated by the piezoelectric fan 300, one corner of the main body 100 deviating from the extension line connecting the suction port 101 and the discharge port 103. Is located in no position. Therefore, appropriate cooling is not performed on the heat source C ′, and it is very difficult to suppress a rise in temperature.

As described above, in the conventional piezoelectric fan 300, the inlet 307 and the outlet 308 are provided on the front side and the rear side of the fan case 306, respectively. The flow is necessarily limited.

Further, in the conventional piezoelectric fan 300, the area of the air sucked from the suction port 307 is also smaller than that of the fan 30.
4 and the size of the fixing plate 305,
This reduction in the suction area causes an increase in pressure loss at the suction port 307 and the like.

For this reason, in the conventional piezoelectric fan 300,
In the above-described portable PC, there is a case where the flow of air inside the device main body 100 cannot be appropriately controlled, and there is a problem that the inside of the device main body 100 cannot be sufficiently cooled.

Therefore, the present invention has been proposed in view of such conventional circumstances, and efficiently inhales air for cooling and freely controls the flow of air inside the mounted equipment. It is an object of the present invention to provide a piezoelectric fan capable of doing so.

[0024]

According to a first aspect of the present invention, there is provided a piezoelectric fan comprising a pair of piezoelectric elements sandwiching a base end of an elastic plate and a diaphragm provided at the other end of the elastic plate. And a case for accommodating the fan inside such that the diaphragm can be vibrated while the base end side of the elastic plate is cantilevered. Then, the case is opposed to a side surface facing the base end portion of the elastic plate, a side surface facing the distal end portion of the diaphragm, and at least one side end portion of both side ends orthogonal to the distal end portion of the diaphragm. It is characterized by having openings on the side surfaces.

In this piezoelectric fan, the opening provided on the side of the case facing the base end of the elastic plate, and the side of the case facing at least one of the two ends of the diaphragm. The opening provided in the case serves as a suction port through which air is sucked, and the opening provided in the side surface of the case facing the tip of the diaphragm serves as a discharge port through which air sucked from the suction port is discharged. .

As a result, in this piezoelectric fan, the suction area of the sucked air can be made larger than that of the conventional fan, and the air can be sucked over a wide range.

Further, in this piezoelectric fan, the size and position of each opening formed in the case can be arbitrarily adjusted according to the arrangement of heat sources inside the device to be mounted and the amount of heat generated. .

Therefore, in this piezoelectric fan, air for cooling can be efficiently sucked in, and the flow of air inside the mounted equipment can be freely controlled.

In this piezoelectric element, a heat radiating plate is provided on the upper surface of the case facing the main surface of the diaphragm.
The heat sink and the heat source may be configured to be thermally connected by a heat pipe. In this case, it is preferable that the connecting portion between the heat pipe and the heat sink is located above the connecting portion between the heat pipe and the heat source.

Thus, in this piezoelectric fan, the heat transfer efficiency of the heat pipe can be improved.

[0031]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIGS. 1 and 2 show a configuration example of a piezoelectric fan to which the present invention is applied.

FIG. 1 is a perspective view showing the structure of the piezoelectric fan 1, and FIG. 2 is an exploded perspective view showing the structure of the piezoelectric fan 1. The arrow shown in FIG.
3 schematically shows the flow of air. 6 to 8 described below, the flow of air is schematically shown by arrows shown in the drawings.

The piezoelectric fan 1 includes a fan 2 and a fan case 3 for housing the fan 2 therein.

The fan 2 has a structure in which a base end of an elastic plate 5 is sandwiched between a pair of piezoelectric elements 4 and a diaphragm 6 is attached to the other end of the elastic plate 5. .

The pair of piezoelectric elements 4 are made of, for example, a substantially rectangular plate-shaped piezoelectric ceramic. As shown in FIG. 3, the pair of piezoelectric elements 4 each have electrodes formed on the entire surfaces of both main surfaces, and these pair of piezoelectric elements 4 sandwich the base end of the elastic plate 5. Electrodes formed on the outer main surfaces of the pair of piezoelectric elements 4 and one end of the power supply circuit 7 are electrically connected, and the elastic plate 5 and the other end of the power supply circuit 7 are electrically connected. When the power supply circuit 7 applies an AC voltage, a current flows from the pair of piezoelectric elements 4 to the elastic plate 5 or from the elastic plate 5 to the pair of piezoelectric elements 4. Also, a pair of piezoelectric elements 4
As shown in FIG. 4, polarization processing is performed in a direction perpendicular to the main surface, and the polarization directions are the same as each other. That is, the pair of piezoelectric elements 4 are subjected to a polarization process such that when one piezoelectric element 4 contracts, the other piezoelectric element 4 expands.

FIG. 3 is a side view showing the structure of the fan 2, FIG. 4 is an enlarged view of the encircling portion A shown in FIG. 3, and arrows shown in FIG. The polarization direction of a pair of piezoelectric elements 4 is shown.

The pair of piezoelectric elements 4 is formed of an elastic plate 5
Are adhered to appropriate positions with respect to the base end portions. In this case, the pair of piezoelectric elements 4 and the elastic plate 5 need to be firmly bonded, and for example, an adhesive made of an epoxy resin is used.

The elastic plate 5 is, as shown in FIGS.
For example, a spring material such as phosphor bronze or a metal material such as stainless steel is formed into a substantially rectangular flat plate shape. As a material of the elastic plate 5, a composite resin material such as carbon fiber or aramid fiber, a plastic material such as polyimide, or the like can be used. The thickness of the elastic plate 5 is appropriately determined according to mechanical properties such as the Young's modulus and specific gravity of the above-described material, and the shape is similarly determined.

The diaphragm 6 is made of, for example, a spring material such as phosphor bronze or a metal material such as stainless steel into a substantially rectangular flat plate shape, similarly to the elastic plate 5. Further, as a material of the diaphragm 6, a composite resin material such as carbon fiber or aramid fiber, or a plastic material such as polyimide can be used. The thickness of the elastic plate 5 is appropriately determined according to mechanical properties such as the Young's modulus and specific gravity of the above-described material, and the shape is similarly determined.

The elastic plate 5 and the vibration plate 6 need to be firmly bonded, and for example, an adhesive made of epoxy resin is used. In some cases, the elastic plate 5 and the diaphragm 6 may be integrally formed.

In this fan 2, as shown in FIG. 3, when an AC voltage is applied by the power supply circuit 7, one of the pair of piezoelectric elements 4 contracts and the other piezoelectric element 4 contracts. It will stretch. As a result, the elastic plate 5 sandwiched between the pair of piezoelectric elements 4 bends and vibrates in the direction of arrow B in the figure according to the polarity of the voltage. Also,
Vibration in the direction of arrow C in the figure is generated at the tip of the diaphragm 6 via the elastic plate 5. At this time, when the natural frequency of the diaphragm 6 and the signal frequency of the AC voltage applied to the pair of piezoelectric elements 4 match, the distal end (free end) of the diaphragm 6 vibrates largely due to resonance. This allows
The fan 2 can send out (or send) air from the base end side of the elastic plate 5 toward the tip end side of the diaphragm 6.

On the other hand, the fan case 3 is formed in a substantially box shape as shown in FIGS. 1 and 2, and the upper surface is sealed by the fan cover 8 while the fan 2 is housed inside. I have.

Here, the fan case 3 holds the fan 2 inside in a state in which the diaphragm 6 can be vibrated while the base end of the elastic plate 5 sandwiched between the pair of piezoelectric elements 4 is cantilevered. Stored in. Specifically, the fan case 3 is shown in FIG.
As shown in FIG. 5, the base end side of the elastic plate 5 sandwiched between the pair of piezoelectric elements 4 is fixed by a support base 9 and a fixing plate 10 provided on one side of the fan case 3. I support it. Note that the support 9 and the fixed plate 10 are
Are fixed by bonding or screwing while sandwiching a pair of piezoelectric elements 4 sandwiching the base end side of the piezoelectric element 4.

Also, on each side of the fan case 3,
Openings 11a, 11b, 11c, 11d are provided respectively. That is, the fan case 3 has an opening (hereinafter, referred to as a first suction port) 11a for sucking air and a first suction port on a side surface facing the base end of the elastic plate 5. 11a, that is, the side surface facing the vibration plate 6
An opening (hereinafter, referred to as an outlet) 11b for discharging air sucked from the first suction port 11a is provided on a side surface facing the tip of the diaphragm 6, and both end portions orthogonal to the tip of the diaphragm 6. Openings (hereinafter, referred to as second suction ports) 11c and 11d for sucking air are respectively provided on the side faces opposite to.

The fan case 3 is provided with a treatment for attaching the piezoelectric fan 1 to another member requiring cooling, for example. Especially for cooling purposes,
A material having a high thermal conductivity, for example, aluminum or the like is used, and at the same time, a surface treatment for increasing the heat radiation of the surface, for example, an alumite treatment, a black dyeing treatment, a sand blast treatment, or the like is performed. Also, the mounting surface of the piezoelectric fan 1
That is, it is desirable that the lower surface of the fan case 3 also has a surface accuracy that maintains good adhesion to the member to be cooled. The shape of the fan case 3 is appropriately determined so that the piezoelectric element 4 and the power supply circuit 7 can be attached thereto.

The fan cover 8 is formed, for example, of aluminum or the like into a substantially rectangular flat plate shape, and is subjected to a surface treatment for enhancing heat radiation on its surface, for example, an alumite treatment, a black dyeing treatment, a sand blast treatment or the like. I have. The fan cover 8 is fixed to the fan case 3 by bonding, screwing, or the like, and seals the upper surface of the fan case 3.

In the piezoelectric fan 1 configured as described above, the fan 2 vibrates inside the fan case 3 as shown in FIG. At this time, the air inside the fan case 3 moves due to the vibration of the diaphragm 6.

In FIG. 6, the arrow in the amplitude direction of the diaphragm 6 indicates the vibration width of the diaphragm 6, and the arrow in a direction substantially perpendicular to the amplitude direction of the diaphragm 6 indicates the diaphragm. 6 schematically shows the magnitude and direction of the moving speed of air according to FIG.

In this case, since the fan 2 is driven at the same frequency, the moving speed of the diaphragm 6 in the vibration direction is
It is proportional to the vibration width of the diaphragm 6. Therefore, the movement of the air caused by the vibration of the diaphragm 6 also becomes maximum near the front end where the vibration width of the diaphragm 6 becomes the maximum displacement. According to Bernoulli's theorem, the pressure of the diaphragm 6 decreases from the base end (fixed end) to the tip end (free end) because the pressure decreases as the velocity of the fluid increases. , At the tip.

From this, the air inside the fan case 3 is blown by the fan 2 from the base end side of the elastic plate 5 to the diaphragm 6.
(The air is blown) toward the tip end side.

Here, as shown in FIG. 7, when the flow of air near the diaphragm 6 is three-dimensionally expressed, the air generated by the vibration of the diaphragm 6 is slightly different depending on the shape of the diaphragm 6 and the like. In addition to the flow moving from the base end side to the distal end side of the diaphragm 6, a flow entering from both end portions of the diaphragm 6 also occurs.

Therefore, in the piezoelectric fan 1 to which the present invention is applied, as described above, the first suction port 11a for sucking air is provided on the side surface of the fan case 3 opposed to the base end of the elastic plate 5. The side of the fan case 3 facing the first suction port 11a, that is, the side face of the fan case 3 facing the tip of the diaphragm 6, discharges air sucked from the first suction port 11a. In addition to the configuration in which the exhaust port 11b is provided, the second side for sucking air into the side surface of the fan case 3 opposite to both side ends of the diaphragm 6 is provided.
The suction ports 11c and 11d are provided.

As described above, in the piezoelectric fan 1 shown in FIG. 1, when the fan 2 vibrates inside the fan case 3, the air for cooling is supplied to the second suction port 11a and the second suction port 11a. The air is sucked into the fan case 3 through the inlets 11c and 11d, and the sucked air is discharged from the outlet 11d.

As a result, in the piezoelectric fan 1, the suction area of the air sucked into the fan case 3 can be made larger than in the conventional case, and the air can be sucked over a wide range.

Therefore, in the piezoelectric fan 1, for example, in a portable PC or the like, it is possible to appropriately control the flow of air inside the device.

For example, in the portable PC shown in FIG. 8, by using the piezoelectric fan 1 to which the present invention is applied, each electronic component 21 serving as a heat source mounted inside the device body 20 is used.
A, 21B, and 21C can be appropriately cooled.

More specifically, the device main body 20 has a suction port 22 for sucking air for cooling at a substantially central portion of one side surface.
In addition, a discharge port 23 for discharging the heat generated inside the device main body 20 to the outside by the piezoelectric fan 1 is provided at a substantially central portion of a side surface facing the suction port 22.

Further, inside the device main body 20, the electronic component 21A (hereinafter, referred to as heat source A) generates the largest amount of heat during operation, and the electronic component 21B (hereinafter, referred to as heat source B) during operation. The calorific value is smaller than the heat source A,
The electronic device 21C (hereinafter, referred to as a heat source C) generates less heat during operation than the heat source B. That is, the amount of heat generated during the operation is: heat source A> heat source B> heat source C.

The piezoelectric fan 1 is arranged such that the outlet 11b faces the outlet 23 of the device body 20. The heat source A is the first of the piezoelectric fans 1.
And is thermally connected to the piezoelectric fan 1 by a heat pipe 24. Heat source B
Is disposed near the second suction port 11c of the piezoelectric fan 1. On the other hand, the heat source C is arranged near the second suction port 11d of the piezoelectric fan 1.

In this case, inside the apparatus main body 20, the heat source A is located in front of the first suction port 11a of the piezoelectric fan 1, and the heat source A and the piezoelectric fan 1 are connected by the heat pipe 24. Therefore, the heat source A is most preferentially cooled. That is, for the heat source A, the generated heat is transported to the piezoelectric fan 1 by the heat pipe 24, and is cooled by the air flowing inside the device main body 20 while absorbing the heat by the forced air cooling action of the piezoelectric fan 1. Is performed. Thereby, the heat source A
Temperature rise can be suppressed.

Further, the heat sources B and C are also disposed near the second suction ports 11c and 11d, respectively, so that
Appropriate cooling is provided.

At this time, since the heat source B generates a larger amount of heat during operation than the heat source C, of the second suction ports 11 c and 11 d provided in the fan case 3,
It is preferable that the opening area of the suction port 11c is larger than the opening area of the second suction port 11d on the heat source C side.

As a result, more air flows inside the apparatus main body 20 from the second suction port 11c on the heat source B side than from the second suction port 11d on the heat source C side.
Since the heat source B, which generates a large amount of heat during operation, is cooled more than the heat source C, the temperature rise between the heat source B and the heat source C can be substantially suppressed as a result.

Therefore, in this portable PC, by using the above-described piezoelectric fan 1, the temperature rise of the heat sources A, B, and C can be suppressed, and the inside of the device main body 20 can be appropriately cooled. That is, this piezoelectric fan 1
According to this, the heat generated inside the device main body 20 can be appropriately discharged to the outside of the device main body 20.

In the piezoelectric fan 1, the position and the opening area of the second suction ports 11c and 11d provided in the fan case 2 are arbitrarily changed, so that
It is also possible to freely control the flow of air flowing through the interior.

Further, in the above-described portable PC, the piezoelectric fan 1 to which the present invention is applied can be arranged in the device main body 20 even if the degree of freedom of design is not high due to design restrictions and the like. Is used, each of the openings 11a, 11b, 11 formed in the fan case 3 according to the arrangement of the heat source inside the device to be mounted, the amount of heat generated, and the like.
By arbitrarily adjusting the size and position of c and 11d, the flow of air inside the mounted equipment can be freely controlled, and efficient cooling can be performed without affecting the exterior design of the main body of the equipment. It is possible to do.

The piezoelectric fan 1 has a configuration in which second suction ports 11c and 11d for sucking air are respectively provided on the side surfaces of the vibration plate 6 of the fan case 3 opposite to both end portions. However, any configuration may be used as long as the second suction port is provided on a side surface of at least one of the two side ends of the diaphragm 6 that faces the one side end. That is, the piezoelectric fan 1 may have a configuration in which an opening is provided only on one side surface of the fan case 3 facing one side end of the diaphragm 6 as necessary.

The above-described piezoelectric fan 1 and heat source A
(The electronic component 11A) is thermally connected by the heat pipe 24, and the heat generated by the heat source A is transported to the piezoelectric fan 1. Generally, when the heat source and the cooling fan are separated from each other, heat is transported by such a heat pipe 24.

The heat pipe 24 is, as shown in FIG.
The inside of the long metal sealed tube 25 is lined (lined) with a capillary substance called a wick 26, and while the inside of the metal sealed tube 25 is made substantially vacuum, a small amount of water called a working fluid 27 or a substitute for Freon is used. Has a sealed structure. The heat pipe 24 has various cross-sectional shapes such as a circle, an ellipse, and a rectangle. The arrows shown in FIG. 9 schematically show the flow of the working fluid 27 moving inside the metal sealed tube 25.

In the heat pipe 24, when one end (high temperature side) is heated, the working fluid 27 evaporates and moves as a vapor flow to the other end (low temperature side). The working fluid 27 that has moved to the low temperature side is cooled and condensed here, and is returned to the high temperature side again in a liquefied state by capillary action due to gravity or wick. By repeating this circulation, the heat pipe 24 can transport the heat generated by the heat source A (high temperature side) to the piezoelectric fan 1 (low temperature side).

In the heat pipe 24, the working fluid 27 condensed on the low temperature side must be efficiently returned to the high temperature side in order to increase the amount of heat transported. Therefore, even when the same heat pipe 24 is used, the amount of heat transported greatly differs due to the step between the high temperature side and the low temperature side or the inclination of the heat pipe 24. For this reason, when the heat pipe 24 is used, it is desired that the arrangement is such that the low temperature side is higher than the high temperature side.

For example, in the above-described electromagnetic fan 200, as shown in FIG. 10, a suction port 203 for sucking air is provided on the upper surface thereof.
A heat radiation plate 28 is provided on the lower surface of the heat pipe 01, one end of the heat pipe 29 is thermally connected to the electromagnetic fan 200 via the heat radiation plate 28, and the heat source 30 and the other end of the heat pipe 24 are thermally connected. Will be connected.

In this case, in the heat pipe 29, since the heat source 30 on the high temperature side and the electromagnetic fan 200 on the low temperature side have approximately the same height, the heat transmission loss increases when transporting heat. Would.

On the other hand, in the piezoelectric fan 1 to which the present invention is applied, as shown in FIG.
1 is connected by the heat pipe 32, the connection between the heat pipe 32 and the fan cover 8 of the piezoelectric fan 1 is located above the connection between the heat pipe 32 and the heat source 31.

More specifically, one end of the heat pipe 32 is in contact with the fan cover 8 sealing the upper surface of the piezoelectric fan 1 and is fixed by the attaching member 33, and the other end is formed on the upper surface of the heat source 31. And is fixed by the attaching member 34. The attachment member 34 for fixing the other end of the heat pipe 32 has a wavy surface to improve heat radiation.

In this case, a step H occurs between the connection between the heat pipe 32 and the fan cover 8 and the connection between the heat pipe 32 and the heat source 31. That is, the low temperature side of the heat pipe 32 can be higher than the high temperature side by the step H. Thereby, in the piezoelectric fan 1, the heat transfer efficiency of the heat pipe 32 can be significantly improved.

In the above description, the case where the present invention is applied to a portable personal computer is taken as an example. However, the present invention is also applicable to a desktop personal computer and the like.
As long as the electronic device has an electronic component serving as a heat source inside the device, the electronic device can be applied to such various types of electronic devices.

[0079]

As described above in detail, according to the piezoelectric fan of the present invention, the suction area of the sucked air can be made larger than before, and the air can be sucked over a wide range. can do. Further, in this piezoelectric fan, the size, position, and the like of each opening formed in the case can be arbitrarily adjusted according to the arrangement of the heat source inside the device to be mounted, the amount of heat generated, and the like.

Therefore, in this piezoelectric fan, air for cooling can be efficiently sucked in, and the flow of air inside the mounted equipment can be freely controlled.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the configuration of a piezoelectric fan to which the present invention is applied.

FIG. 2 is an exploded perspective view showing a configuration of the piezoelectric fan.

FIG. 3 is a schematic side view showing a configuration of a fan.

FIG. 4 is an enlarged side view of a main part A in FIG. 3;

FIG. 5 is a sectional view showing a configuration of the piezoelectric fan.

FIG. 6 is a sectional view showing a vibration state of the piezoelectric fan.

FIG. 7 is a schematic perspective view showing the flow of air near the diaphragm in a three-dimensional manner.

FIG. 8 is a schematic plan view showing an example of the arrangement of each electronic component serving as a heat source and a piezoelectric fan mounted inside the device main body.

FIG. 9 is a cross-sectional view illustrating a configuration of a heat pipe.

FIG. 10 is a perspective view showing a state in which an electromagnetic fan and a heat source are thermally connected by a heat pipe.

FIG. 11 is a perspective view showing a state in which a piezoelectric fan and a heat source are thermally connected by a heat pipe.

FIG. 12 is a perspective view schematically showing a flow of air flowing inside a device main body in the portable PC.

FIG. 13 is a perspective view illustrating a configuration of an electromagnetic fan.

FIG. 14 is a cross-sectional view of a main part showing a state in which an electromagnetic fan is mounted inside the device main body.

FIG. 15 is a perspective view showing a configuration of a conventional piezoelectric fan.

FIG. 16 is a cross-sectional view of a main part showing a state in which a piezoelectric fan is mounted inside the device main body.

FIG. 17 is a plan view showing a flow of air in a fan case of the piezoelectric fan.

FIG. 18 is a schematic plan view showing an example of the arrangement of electronic components serving as heat sources and the piezoelectric fan mounted inside the apparatus main body.

[Explanation of symbols]

1 piezoelectric fan, 2 fans, 3 fan case, 4
Piezoelectric element, 5 elastic plate, 6 diaphragm, 7 power supply circuit, 8
Fan cover, 9 support base, 10 fixing plate, 11a
Opening (first suction port), 11b opening (discharge port),
11c, 11d opening (second suction port), 20 apparatus main body, 21 electronic component (heat source), 22 suction port, 23 discharge port, 24, 29, 32 heat pipe

Claims (3)

[Claims] 1. A fan having a base end side of an elastic plate sandwiched between a pair of piezoelectric elements, and a diaphragm attached to the other end side of the elastic plate; and a base end side of the elastic plate. A case that accommodates the fan in a state where the diaphragm can be vibrated while the cantilever is supported, and the case has a side surface facing a base end of the elastic plate;
A piezoelectric fan, characterized in that openings are provided on a side face facing the tip of the diaphragm and on a side face facing at least one of the two side ends of the diaphragm. 2. The piezoelectric fan according to claim 1, wherein the position and the area of each of said openings are made different depending on the arrangement of heat sources and the amount of heat generated. 3. A radiator plate is provided on an upper surface of the case facing a main surface of the diaphragm, and the radiator plate and a heat source are thermally connected by a heat pipe. 2. The piezoelectric fan according to claim 1, wherein a connection portion with the heat sink is located above a connection portion between the heat pipe and the heat source. 3.