JP2008240590A - Turbo fan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbo fan having higher static pressure and less noises. <P>SOLUTION: Blades 8 of an impeller 4 are erected on the peripheral edge of a base disc 4a, and fixed at their ends to an annular plate 4b. The diameter of the inside edge of the annular plate is almost equal to the inner diameter of a bell-mouth provided on the air suction side of a casing. The blades each consist of a curved portion and an extending portion, and the curved portion is covered with the annular plate and the extending portion 8a is protruded from the inside edge of the annular plate to the rotation center side. The pitch at the end of the extension portion is 5 mm or so, so that a sucked air stream is segmentalized and fed into gaps between the blades to deliver less-pulsated wind into a cavity of the casing with centrifugal force. For example, although the number of the blades are greater and the rotating speed is higher than those of current products in a washing and drying machine, noises are reduced by 5 dB or more with the same air volume to produce high static pressure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure of a turbofan used in a laundry drying apparatus or the like.

  A conventional turbofan 100 includes a casing 101, an impeller 102, and a rotating shaft 103 thereof as shown in a front view in which a part of FIG. The impeller is composed of a main disk 104 attached to the rotating shaft and a blade 105 erected on the peripheral portion thereof, and an annular plate 106 shown in FIG. To form a kind of bowl. The direction of rotation of the impeller is the direction of the arrow shown in the figure. The pitch p of the outer peripheral edge of the blade is uniform and the blade thickness t is also constant. Reference numeral 107 denotes an outlet. The side view of the impeller 102 is shown in FIG. The height of the inner peripheral edge of the blade is higher than the height of the outer peripheral edge, and the side shape is a trapezoid. A bell mouth 101a is provided at the outside air suction port of the casing 101 to urge suction. The diameter d of the inner peripheral edge of the blade is substantially equal to the diameter D of the bell mouth. It is presumed that the intention to increase the static pressure is increased by increasing the suction amount of outside air by increasing the inner peripheral edge of the blade and lowering the height of the outer peripheral edge.

  In recent years, a washing and drying machine does not release moisture to the outside of the machine, configures a circulation system that blows dry warm air from one of the drums whose rotation shaft is inclined, and takes out humid air from the other, and the circulation path Has a heat exchanger. The heat exchanger uses a heat pump method to rapidly cool damp air to remove water droplets and heat the cold air to circulate it into hot air to blow hot air on the wet laundry in the drum. Since the heat exchanging portion of the heat exchanger is arranged in close contact with the intake side of the blower incorporated in this circulation system path, resistance is generated in the air supply circulation path and a blower with high static pressure is required. In addition, the washing and drying machine is a sealed container, and noise and vibration accompanying rotation of the blower propagate to the container, and the noise around the container may be felt particularly high. People who have finished their work due to fewer customs of hanging laundry outdoors will do laundry at night, but noise is particularly a problem when washing and drying at midnight.

Japanese Laid-Open Patent Publication No. 2007-2708 is cited as a document in which static pressure is increased with a small turbofan and there is little noise during operation. The use is a ceiling embedded type air conditioner, and the trailing edge of the impeller blade is formed into a curved surface with a small curvature so as to avoid the generation of turbulent flow and provide a turbo fan with less noise. Moreover, although the front edge part of a blade | wing protrudes from the inner edge part of an annular | circular shaped shroud, there is no special description about the effect. The blades are considerably inclined with respect to the radial direction of rotation.
JP 2007-2707 A

  To provide a turbo fan with low noise disposed in a ventilation circulation path for air conditioning such as drying or heat dissipation.

  The turbofan of the present invention has a casing whose radius of curvature gradually increases when shown in a cross-sectional shape perpendicular to the rotation axis, a base disk that rotates on a plane orthogonal to the rotation axis, and a plurality of curved shapes that stand up at the peripheral edge thereof. And a circular plate covering the other end of the blade, the curved surface of the blade forms a tangent in the radial direction of the base disk, and the inner edge of the blade is the inner side of the annular plate It is characterized by including an impeller that integrally or separately forms a blade portion protruding in the direction of the rotation center from the peripheral edge portion. In addition, the diameter of the contact circle of the inner edge of the blade is made smaller than the inner diameter of the bell mouth (intake port) provided on the intake side of the casing, thereby improving the intake rectification effect and preventing the generation of vortex. The position of the contact point between the curved surface and the tangential line in the radial direction of the base disk is 0.5 W as the distance from the outer peripheral edge of the blade to the contact point, where W is the width of the blade measured parallel to the tangent line. The range in which the noise level does not change is preferably 0.4 to 0.6 W.

  The protruding blade portion is a member that forms the curved surface, a plane extending along the tangential direction of the curved surface, a curved surface extending along the curvature radius of the curved surface, or both protruding blade portions are defined. It constitutes an extension formed at the site.

  Although the protruding blade portion is formed of a member integrated with a member forming the curved surface, the present invention is not limited to this. A blade corresponding to the extended portion may be separately prepared and fixed to the base disk. In this case, since the annular plate does not exist on the other side of the protruding blade part, a structure to be fitted to a part of the blade is formed and fixed to the circular plate, and the number of the blades also forms a curved surface The number of copies is not necessarily the same as the number of copies. In addition, the present invention includes that the curvature radius of the curved portion of the blade is not constant but includes curved surfaces having different curvature radii.

  In addition, the gap between the inner edge portions of the blades protruding from the inner peripheral edge portion of the annular plate is preferably set to about 5 mm when the outer diameter of the impeller is about 150 mm. As a result, fine air can be supplied and the static pressure increases when a heat exchanger or the like blocks the air circulation path, but the pulsating wind flow generated at this time is eliminated, and vibration due to pulsation propagates to the side of the casing. Since no fixed vibration sound is generated, the effect of reducing the noise propagating to the entire drying container is obtained. Furthermore, when the outer diameter of the impeller increases, the air volume required for the turbofan increases, so the blade height, width, and blade thickness also increase and the amount of outside air sucked in increases. It is necessary to make it larger than 5 mm. In short, it is an essential condition that no vortex flow is generated when the outside air flows between the blades.

  Further, as described above, since the curved surface of the blade is at a position that forms a tangent line in the radial direction, the inclination of the blade with respect to the radial direction is small, and the flow of wind divided by the blade protruding from the annular plate is reduced. Furthermore, since it rectifies | straightens and it blows off to the outer peripheral direction of an impeller, it has the characteristic that it is hard to generate | occur | produce a turbulent flow between blades. Since the blades of the impeller of a conventional turbofan have a large inclination angle with respect to the radial direction, the airflow between the blades tends to be faster because the air sucked from the bell mouth is accelerated rapidly. The airflow flowing from the bellmouth is a cause of vortex flow when flowing into the blades. In the present invention, since the blades are arranged in the radial direction, the airflow between the blades is not so fast. Therefore, it is considered that the flow rate between the air blades is reduced, but the number of blades is increased, and the air flow rate as a whole of the impeller is not so changed. As will be described in the embodiment, when the discharge air volume per minute is the same, the rotational speed of the product of the present invention is about 13% higher than that of the conventional product. However, the reason for the low noise seems to be one of the reasons mentioned above.

  As a result of various studies on the shape of the impeller, if the length of the curved blade is W parallel to the radial direction of the impeller, the extended portion protruding from the annular plate is about 0.2 to 0.3 W. In addition, the cross-sectional shape of the extended portion is preferably a straight line in the tangential direction of the curved portion or a curved line extending along the radius of curvature of the curved portion, and the noise tends to become stronger when exceeding this range.

  The washing / drying machine equipped with the turbofan of the present invention had a low noise level of at least 5 dB when the background noise was 21.8 dB. When the door of the room where the washing / drying machine was installed was closed, almost no operation noise was heard. There was a tendency for the drying speed to be faster than the current product.

  As an example, a turbofan of a size that can be mounted on a washing / drying machine is created, and an impeller with a diameter of 150 mm and a height of 35 mm is used to have an extension portion of a blade protruding from the inner diameter of the bell mouth. Provide a turbo fan with low noise. In this example, a relatively small turbofan will be described. However, even in a turbofan using an impeller having a larger outer diameter, such as a very large fan such as a building blower, the inner edge of the blade is By forming a blade portion that protrudes from the inner peripheral edge portion of the annular plate, wind rectification is performed, and a turbo fan with low noise and high static pressure can be provided.

Example 1
FIG. 1 (a) is a front view showing a state in which a side plate including a bell mouth of a turbofan 1 of the present invention and an annular plate of an impeller are removed. Reference numeral 2 denotes a casing, and the inner surface has a spiral shape in which the radius of curvature R1 with the rotating shaft 3 as the center is gradually increased, and a blowout port 5 is provided on the side where the outer peripheral edge of the impeller 4 and the inner surface of the casing are larger. ing. A circle indicated by a one-dot chain line indicates the inner diameter of the bell mouth (intake port). FIG. 1B is a side view of the impeller 4 and shows the positional relationship between the side plate 2 a and the bell mouth 6 with respect to the inner end of the blade 8. The direction of the suction airflow from the bell mouth when the impeller 4 rotates is indicated by an arrow.

  FIG. 2 is a perspective view showing the entire turbo fan 1 of the present invention, and a bell mouth 6 is provided on the side plate 2a. The side plate 2 b is an attachment board, and a motor 7 is attached to the board, and the impeller 4 is attached to the rotary shaft 3. FIG. 3 is a perspective view of the impeller 4. A circular base disc 4a having a boss attached to the rotating shaft 3 of the motor as a central part and one end of the blade 8 on the periphery thereof are concentrically arranged. A plurality of pieces are fixed vertically, and the other end of the blade 8 is fixed to an annular plate 4b (only a part is shown). The diameter of the inner edge of the annular plate is set to be approximately equal to the diameter of the bell mouth. The blade 8 protrudes from the inner edge of the annular plate 4b to form an extension 8a, which is an important element of the present invention. The base disc 4a and the annular plate 4b are arranged in parallel, and the blades are 0.6 mm thick aluminum plates. Although not shown in particular, the fixed portion of the blade is provided with bending margins at both ends of the blade and inserted into holes formed in the base disc and the annular plate to bend and fix. In this embodiment, the curvature radius of the curved portion of the blade is 40.4 mm, and an aluminum plate having a thickness of 0.6 mm is bent and used.

  FIG. 4A is an enlarged cross-sectional view of a plane perpendicular to the rotation axis showing a part of the blade 8. The blade 8 covered with the annular plate 4b is a plate made of a curved surface with a predetermined radius r, and forms a contact P with a radial tangent extending from the center of the rotating shaft 3 of the impeller. The extension part 8a of the blade | wing protruded from the inner edge part of the annular plate 4b shows the case where it is extended with the straight line in the tangent direction of the curvature radius r of a blade | wing. FIG. 4B is an enlarged view of the blade, and is an example in which the extension portion 8a of the blade forms an extension portion with the same curvature radius r as the curvature radius of the blade. Although there is no change in the noise level in the range of these extensions, the radius of curvature r2 is smaller than the radius r of the curved portion or the radius of curvature r2 in the reverse direction as in the extension 8c as shown in FIG. If the extension is formed, the noise tends to increase. When the outside air is sucked in, the outside air is subdivided and the wind is sent into the gap between the blades. If the blade width parallel to the radial tangent line including the curved portion and the extended portion of the blade is W, the position of the contact point P is the position of the distance W1 from the outer edge of the blade. The angle with respect to the tangent of the blade is set at a position corresponding to 5 W, that is, a half of the blade width, but corresponding to 0.4 to 0.6 W. Similarly, the reference value of the width W2 of the extension portion 8a can be set in a range of 0.2 to 0.3 W with W / 4 as a reference value. In other words, W / 4 indicates that the length of the portion covered by the annular plate and the length of the extension portion is a ratio of 3: 1. By setting within these ranges, the inclination of the blade and the length of the extension portion 8a with respect to the tangent of the curved portion set to a predetermined r passing through the center of the rotating shaft 3 of the blade are defined. When the contact point P is less than 0.4 W, the blown air volume decreases. When the contact point P is greater than 0.6 W, the blades are inclined more with respect to the tangential line in the radial direction, and noise becomes significant. Further, when the width W2 of the extension is smaller than 0.2W, noise is increased, and when it is larger than 0.4W, the gap at the tip of the extension is narrowed and the suction amount is reduced and the blown air volume is reduced.

  The inclination of the blade will be described with reference to FIG. (A) The figure shows a blade 8 having a tangent to the curved surface of the vertical blade 8 passing through the center of the rotating shaft 3 and its contact point P. The contact point P is a half position when the blade width is W, that is, 0.5 W. (W1). The width W2 of the extension portion 8a is set to a length corresponding to 0.2W. The figure (b) is a contact when the contact P is changed to P1, and the length W1 from the outer edge part of the blade | wing parallel to a tangent corresponds to 0.6W. The arrangement | positioning of the blade | wing at this time is shown by the blade | wing 8-1, and the inclination | tilt angle of the blade outer edge part with respect to a tangent becomes large. The width W2 of the extension portion with respect to the blade width W is set to 0.2W. The figure (c) shows the arrangement state of the blades 8-2 when the contact P is changed to P2. The distance W1 from the outer edge of the blade is a length corresponding to 0.4W. The inclination angle of the outer edge of the blade with respect to the tangent is reduced, but the inclination angle of the extension with respect to the tangent is increased. The length W2 parallel to the tangent line of the extension portion was set to a length corresponding to 0.3W. As described above, when the position of the contact point P between the curved portion of the blade and the tangent line passing through the rotation shaft 3 is changed, the inclination angle of the blade changes and the influence on the air volume, static pressure, and noise during operation becomes significant. It should be noted that the gap G along the inscribed circle at the end of the extension 8a needs to be 3 to 5 mm. If it is narrower than 3 mm, the air volume becomes extremely small. Increases and reduces static pressure.

(Example 2)
The result of noise measurement with the turbo fan 1 of Example 1 attached to the washing / drying machine is shown in FIG. The washer / dryer uses TW-2500VC manufactured by Toshiba Corporation. The current product before the present invention is compared with the present product. FIG. 6A is an external view of the washing / drying machine 10, which has a front opening door 10a, and rotates in a state where the drum is inclined behind the inspection window 10b. Outline dimensions are 665mm in width, 714mm in depth, 1100mm in height, the front door is curved and receded, and the depth of the top plate is 550mm. The measurement position of the noise was measured by installing a microphone 1 m in front of the observation window, 1 m away from the center of the right side of the aircraft, and 1 m away from the center of the left side. The table in (b) shows the case where the blower air volume of the turbo fan is 2.0 m ³ / min, and the figure (c) shows the case where the air volume is 2.5 m ³ / min. The noise is 5.4 dB lower despite the high rotational speed of the product of the present invention.

  The washing dryer uses a heat pump system to cool the damp air that has passed through the wet laundry with a heat exchanger, remove water droplets to lower the humidity, and heat the air containing the remaining moisture again with the heat exchanger. Circulating the action of spraying on the laundry. Therefore, in the explanatory view shown in FIG. 7, warm air is sent to the drum 11 through the pipe 13 on the intake side and the blow-out side of the turbofan 1, and high-humidity air containing the moisture of the laundry is discharged from the drum to the heat exchanger 12. It is sent to. Air with high humidity is cooled by the first heat exchanger to remove the moisture as water droplets, and further heated by the second heat exchanger to send warm air to the drum. This is repeated to dry the laundry. Since the radiator mesh of the heat exchanger is arranged so as to block the circulating air flow path, the burden on the turbofan increases. This is why there is a need for a turbofan that has the ability to generate wind with high static pressure and low pulsation.

  In view of the current situation in which houses with a high degree of sealing are widespread and exhaust to the outside is limited, the demand for washing and drying machines is great. The turbofan of the present invention is an effective means for reducing noise, as heat pump dryers become widespread and noise countermeasures are required. Further, by utilizing the low noise and high static pressure, it is possible to absorb the hot air staying in the computer rack, cool it by a heat pump system and circulate it in the rack to prevent the CPU from being heated. Furthermore, since the heat pump system is used in air conditioning equipment that adjusts indoor humidity, temperature, and ventilation, the air conditioning efficiency can be increased by using the turbofan of the present invention in the heat exchange part of the heat pump.

(A) A figure is a front view of the turbofan of this invention, (b) A figure is a side view of an impeller. Example 1 It is a perspective view showing the whole turbofan of the present invention. Example 1 It is a perspective view of the impeller of the present invention. Example 1 (A) It is explanatory drawing which shows the attachment form of a blade | wing, (b) A figure is explanatory drawing which shows the detail of a blade | wing, (c) A figure is explanatory drawing which shows another shape of a blade | wing. Example 1 (a), (b) and (c) is an explanatory view showing the arrangement state of the blades accompanying the change of the position of the contact point of the blade and the tangent. Example 1 (A) A figure is explanatory drawing which shows the noise measurement position of a washing-drying machine, (b) And (c) figure is a table | surface which shows a measurement result. (Example 2) It is explanatory drawing which shows the drying mechanism of a washing dryer. (Example 2) (A) is a front view of a conventional turbofan, and (b) is a side view of an impeller. Example 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbo fan 2 Casing 3 Rotating shaft 4 Impeller 5 Outlet 6 Bell mouth 7 Motor 8 Blade 10 Washing-dryer 11 Drum 12 Heat exchanger 100 Conventional turbo fan

Claims (6)

  A casing in which the radius of curvature of the cross-sectional shape perpendicular to the rotation axis gradually increases, a base disk that rotates in a plane orthogonal to the rotation axis, a plurality of curved blades standing on the periphery thereof, An annular plate covering the other end, the curved surface of the blade forms a tangent passing through the rotation axis in the radial direction of the base disk, and the inner edge of the blade is the inner peripheral edge of the annular plate A turbofan including an impeller that forms a blade portion protruding from the portion toward the rotation center.   The protruding blade portion is formed on a plane extending along the tangential direction of the curved surface of the blade, a curved surface extending along the radius of curvature of the curved surface, or a portion between both protruding blade portions. The turbo fan according to claim 1.   When the width of the blade in the direction parallel to the radial tangent of the base disk of the curved surface of the blade is W, the distance between the contact point P between the curved surface and the tangent and the outer peripheral edge of the blade is 0.4-0. The turbo fan according to claim 1, wherein the turbo fan is set to a range of 0.2 to 0.3 W.   The turbofan according to any one of claims 1 to 3, wherein the turbofan is used for blowing air in a drying circulation path of a washing and drying machine.   The turbofan according to any one of claims 1 to 3, wherein the turbofan is used for blowing air in a cooling path for cooling hot air radiated by a CPU of a computer.   The turbofan according to any one of claims 1 to 3, wherein the turbofan is used in an air conditioner that adjusts at least one of humidity, temperature, and ventilation.

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