Patent Application
20100065260
The present invention relates to an apparatus to cool a heat generating source in equipment of electronic devices, and in particular, to a cooling apparatus which employs a vibration generator and which is mounted in an electronic device.
With recent progress of technologies, portable electronic apparatuses are increasingly being downsized; on the other hand, both of the calorific value and calorific density tend to become greater due to developed efficiency of the apparatuses and high-density mounting of electronic parts.
In electronic apparatuses such as portable telephone terminals of which the size is particularly reduced, it is quite difficult to mount a mechanism to diffuse heat generated in a cabinet; even if the mechanism is mounted, it is difficult to efficiently convect air in the cabinet of which the size as well as thickness are remarkably reduced.
One of the reasons therefor will be that it is difficult to secure in the cabinet a space required to mount a fan and the like. In addition to a fan section which actually generates wind, there is also required a motor to generate rotational force; in a case of a general fan in which a motor is installed on a center of rotating blades, its diameter is ten mm or more and its size is almost equivalent to thickness of portable terminal apparatuses.
Patent Document 1 discloses a configuration in which fan blades are attached to an axle of a vibration generating motor beforehand mounted in a portable telephone terminal or the like. This is a configuration in which the fan blades also rotate according to the motor rotation. A vibrator is coupled with the motor by “clutch mechanism” according to necessity.
In this configuration, a certain clutch mechanism is required; in addition, since the vibrator and the clutch mechanism are on the lee side of the fan, it is necessary to keep a wind flow rate by increasing the diameter of the fan.
To make it compact by removing gears, it will be considered to connect the motor, the vibrator, and the fan blades in series. However, for the portable-type electronic devices for which the downsizing is underway, the space in the devices is increasingly becoming quite smaller; hence, it is likely that the motor interrupts the air flow in the arrangement.
Also, the principle to cause the air flow is the same as that of the rotating fun of conventional type; basically, the size thereof is only reduced.
Patent Document 2 discloses a construction in which fan blades of vibration generator built-in type is arranged at the lee-most position. By use of the construction in which the fan blades can be rotated according to the motor rotary direction, the clutch mechanism is simplified. However, it is inevitable that as for the volume in the cabinet, the volume to mount the fan is additionally required.
Patent Document 3 proposes a swing-type fan employing a piezoelectric element. By adopting a piezoelectric element, the apparatus to be mounted additionally includes new power consuming parts and heat generating elements. Also, an electric circuit to manage operation of the piezoelectric element is required to be arranged. Moreover, the wind flow rate is restricted by quantity of deformation of the piezoelectric element having relatively high rigidity.
For recent portable-type electronic apparatuses designed in micron units, the removal of the cooling problem is an important issue; to keep predominance in the market of apparatuses, it is essential that they are small in size. In these apparatuses of which performance is being enhanced, the cooling construction which relies upon heat conduction is approaching its limit today.
Patent Document 4 discloses an invention in which a cooling medium is sealed in a tube such that by vibrating the tube, heat conduction is urged; however, in a portable terminal of which size and weight are required to be reduced, it is difficult that the tube is installed in the terminal and the liquid as the cooling medium is kept in the terminal. That is, the configuration of the invention disclosed by Patent Document 4 is not applicable to portable terminals.
The present invention has been devised in consideration of these problems and aims to provide an energy-saving vibration generating and cooling apparatus with a small volume in which convection is caused inside and outside its cabinet by use of a mechanism to generate vibration and which can efficiently transfer heat.
To achieve the above object, the present invention provides a vibration generating and cooling apparatus, characterized by including a motor, a magnetic eccentric plummet mounted onto a rotary shaft of the motor, and a magnetic member indicating magnetism disposed physically apart from the eccentric plummet, wherein the magnetic member repeatedly approaches and leaves the eccentric plummet in association with rotations of the eccentric plummet and a to-be-cooled object is cooled by a jet created by the movement of the magnetic member.
In the present invention, it is favorable that the magnetic member is a diaphragm arranged to enclose a predetermined space excepting at least one nozzle section, and when the diaphragm deforms in association with the rotations of the eccentric plummet, fluid in the predetermined space is ejected as the jet from the nozzle section and is blown onto the to-be-cooled object.
Moreover, in accordance with the present invention, it is favorable that the magnetic member is a piston arranged to enclose a predetermined space excepting at least one nozzle section, and when the piston is dislocated in association with the rotations of the eccentric plummet, fluid in the predetermined space is ejected as the jet from the nozzle section and is blown onto the to-be-cooled object. In addition, the piston is favorably monoblock-molded using a magnetic substance and a resin material. Also, more favorably, at least one of the nozzle sections is arranged to generate the jet in a direction different from a stroke direction of the piston.
Alternatively, in the present invention, it is favorable that the magnetic member is a swing fan disposed in a duct physically connected to a heat generating element and a jet generated in the duct when the swing fan swings in association with the rotations of the eccentric plummet cools the duct heated through heat conduction from the heat generating element; additionally, more favorably, projections and depressions are formed on an inner wall surface of the duct.
In accordance with the present invention, it is possible to provide an energy-saving vibration generating and cooling apparatus with a small volume in which a convention is caused inside and outside its cabinet by use of a mechanism to generate vibration and which efficiently transfers heat. It is hence possible to mount more efficient electronic parts while coping with the downsizing of apparatuses.
Description will be given of a first exemplary embodiment favorably carrying out the present invention by referring to drawings.
As an example of the cooling construction responding to the magnet movement, description will be given of a method employing a synthetic jet. By moving a piston or the like in the sealed configuration excepting an opening for exhaust and intake, a flow passing the opening is generated by use of a change in the volume of the sealed construction.
In the intake, air in the vicinity of the nozzle 6 is sucked; in the exhaust, the air is discharged linearly from the nozzle 6 toward a distant point; hence, quite a small amount of air in the cabinet can be efficiently circulated.
The vibration generator in accordance with the present embodiment is applicable to a small-sized electronic apparatus in which the conventional cooling mechanism using the convection cannot be easily mounted. In a cooling construction in which heat is transferred to the cabinet primarily through the heat conduction, there exists a problem that the cabinet is locally heated to a high temperature; however, in the present embodiment, a flow of air is generated in the sealed space in the cabinet; hence, in addition to the cooling of the electronic part, there is attained an advantage that the surface temperature of the cabinet is uniform.
As
When a cylinder having a diameter of 10 mm and a stroke of 1 mm is formed and the vibrator 1 is rotated with the number of rotations of 1000 turns per minute which is equal to or less than one tenth of that for the vibration generation, a jet flow equal to or more than 40 cm per second can be generated even if the contour of the nozzle 6 is limited to 1 mm×3 mm. This indicates that, when compared with an 8 mm square small-sized fan, a flow speed of about 40% is attained while lowering the number of turns to one fifteenth.
For the small-sized fan, although the thickness of the fan itself is reduced to 2 mm, the thickness direction is the wind flowing direction; hence, it is required to dispose a space to flow the wind; in consideration of a thin-type device cabinet, it is quite difficult to employ an arrangement in which the heat generating element is placed in the wind flowing direction.
For the synthetic jet 7, it is not required to arrange the nozzle 6 in the vibrating direction of the piston 5; as shown in
In the vibration generator according to the present embodiment, an air flow having stirring effect in the cabinet can be generated by use of quite a small space in the electronic device. That is, the size thereof can be reduced when compared with the configuration in which a fan is mounted. Moreover, by altering the synthetic jet diameter (the nozzle contour), the flow speed is changeable while keeping the flow rate unchanged; hence, the cooling effect can be more efficiently attained when compared with the construction in which the fan diameter directly affects the flow rate.
Description will be given of a second exemplary embodiment which favorably embodies the present invention.
In this embodiment, the vibration unit which operates in response to the magnet vibrator is implemented by a diaphragm. In the configuration, the abrasive resistance which takes place during the operation of the piston is removed, and it is possible to simplify the construction by directly mounting the diaphragm itself on the inner wall of the cabinet.
In general, a projecting section onto which a diaphragm 13 is to be attached is disposed on an inner surface of a cabinet 8 on the side of a vibrator 12 of a motor 11 held by the cabinet 8 inside the cabinet. A nozzle 15 is formed by not arranging the projecting section partially on the inner surface which faces an electronic part mounted on a printed board 9. And as
It is ideal to adopt a thin, flexible magnet sheet for the diaphragm 13. There has been developed a 1 mm thick magnet sheet which is produced through monoblock-molding by use of powder of a magnetic substance and which has flexibility and elasticity. By adhering such magnet sheet onto the projecting section of the cabinet inner wall, the volume of the cylinder construction for jet generation can be minimized.
As for the magnetic force, although depending on the sheet thickness, since the sheet-shaped magnet is made to swing in the present embodiment, sufficient effect is attainable even if the thickness is equal to or less than 1 mm. Hence, it is favorable to provide flexibility to the sheet including a magnetic material which is inherently not flexible by reducing the sheet thickness to 0.5 mm or less.
Description will be given of a third exemplary embodiment which favorably embodies the present invention.
As shown here, even for a small-sized electronic device such as a mobile telephone terminal 16, it is possible, by disposing a duct 17, to effectively collect heat on an inner wall of the duct 17. Hence, if cooling convection can be efficiently caused in the duct 17, a flow can be generated outside the cabinet by use of a magnet vibrator 1 arranged in the cabinet.
As
Further, the availability of a high inner surface of the duct 17 (a great surface area of the inner surface) is advantageous to transfer heat to the air passing through the duct 17.
In this way, by use of a magnet as the vibrator, the cooling mechanism can be operated without using mechanical connection. Hence, when a reciprocal-type fan is disposed in the cooling duct arranged outside the cabinet, the fan outside the cabinet can be operated by using a vibration generator existing inside the cabinet having a dustproof and waterproof function.
The respective exemplary embodiments described above are favorable examples of the present invention, and the present invention is not restricted by them.
For example, the present invention is applicable not only to the mobile telephone terminal, but also to any portable-type electronic apparatus in which a semiconductor device is employed such as a notebook-type computer, a portable-type game machine, a portable-type reproducer, or a PDA.
In this fashion, various variations are possible for the present invention.
This application is based upon and claims the benefit of priority from Japanese patent application No. 2007-073573, filed on Mar. 20, 2007, the disclosure of which is incorporated herein in its entirety by reference.
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| Number | Date | Country | Kind |
|---|---|---|---|
| 2007-073573 | Mar 2007 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2008/053001 | 2/21/2008 | WO | 00 | 9/1/2009 |
