JP2007113476A - Electric blower and vacuum cleaner using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric blower with reduced noise, by largely reducing high-frequency sound especial in sound pressure level generated in an impeller near the acoustic source. <P>SOLUTION: The electric blower comprises: an impeller 5 having a plurality of blades 4; an air guide 7 having a plurality of stator vanes 6 disposed to surround the impeller; a fan case 10 housing the impeller 5 and the air guide 7, and having an intake port 8 at its center part and an exhaust port 9 in its side face; an electric motor 11 rotary-driving the impeller 5; a soundproof tube 13 covering the side face of the fan case 10 and a whole electric motor and having an exhaust port 12; and a muffler 16a disposed to a side face of the electric motor and having narrow two recess parts 15a which are the same in width toward a rotational shaft 14 of the impeller 5 and are different in depth and are formed on its circumference. Therefore, a particular frequency of high-frequency sound waves leaked from the exhaust port 9 of the side face of the fan case 10 can be reduced by resonance effects of each of two narrow recess parts 15a when the sound waves are propagated in an air passage between the soundproof tube 13 and the muffler 16a. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric blower that reduces high-frequency sound generated during operation and a vacuum cleaner using the same.

Conventionally, this type of electric blower has a silencer interposed in the middle of an air passage and having an enlarged portion that enlarges the passage cross-sectional area in a cylindrical shape (see, for example, Patent Document 1).
JP 2001-032798 A

  However, since the silencer is not provided near the exhaust port of the fan case in the conventional configuration shown in FIG. 9, the high-frequency sound having a protruding sound pressure level generated due to the rotation speed of the impeller and the number of blades. However, there is a problem that a sufficient silencing effect cannot be obtained. For this reason, an operator may hear an unpleasant driving sound during cleaning and receive an unpleasant impression.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a low-noise electric blower that significantly reduces high-frequency sound having a protruding sound pressure level generated by an impeller near a sound source.

  In order to solve the above-described conventional problems, an electric blower of the present invention includes an impeller having a plurality of blades, an air guide having a plurality of stationary blades arranged around the impeller, and an air guide including the impeller and the air guide. A fan case having an intake port at the side and an exhaust port on the side surface, an electric motor for rotationally driving the impeller, and a soundproof cylinder having an exhaust port that covers the side surface of the fan case and the entire motor with a gap provided And a silencer provided with a short width recess having a depth in a substantially radial direction of the rotating shaft of the impeller, and the silencer is provided on a side surface of the motor.

  As a result, when sound waves including high frequency sound leaking from the exhaust port of the fan case propagate through the air passage between the soundproofing cylinder and the silencer, the silencer provided on the side surface of the motor is determined by the depth of the recess. The sound of a specific frequency comes to be reduced by the resonance effect, and becomes a low noise electric blower.

  The electric blower of the present invention can significantly reduce high-frequency sound having a protruding sound pressure level generated by an impeller near the sound source, and can realize low noise of operation sound.

  According to a first aspect of the present invention, an impeller having a plurality of blades, an air guide having a plurality of stationary blades disposed around the blade, an air guide having an air inlet at the center and containing the impeller and the air guide, and an air outlet on a side surface A fan case having a motor, a motor that rotationally drives the impeller, a soundproof cylinder having an exhaust port that covers the side surface of the fan case and the entire motor, and a substantially radial direction of the rotating shaft of the impeller And a silencer provided with a short-width recess having a circumferential depth in a circumferential shape, and by using the electric blower provided on the side of the motor as the silencer, sound waves including high-frequency sound can be generated from the exhaust port of the fan case. When propagating through the air passage between the soundproofing cylinder and the silencer, a sound with a specific frequency determined by the depth of the short recess is silenced by the resonance effect at the silencer provided on the side of the motor. , Sound pressure level which projects the high frequency sound without lowering the efficiency of the dynamic blower can be reduced. Furthermore, since the concave portion of the silencer is provided on the circumference, high-frequency sound that has passed through the air passage between the electric motor and the soundproofing cylinder can be reduced regardless of the propagation direction of the sound wave.

  In the second aspect of the invention, in particular, the silencer of the first aspect of the invention is an electric blower having a shape having a plurality of short-width concave portions having different depths, so that sound waves including high-frequency sound are emitted from the exhaust port of the fan case. When propagating through the air passage between the soundproofing cylinder and the silencer, multiple sounds with different frequencies determined by the respective depths in the recesses of the silencer are silenced by the resonance effect, reducing the efficiency of the electric blower A plurality of high-frequency sounds having different frequencies can be reduced at a time without causing them.

  The third invention is particularly limited in that the plurality of short-width concave portions having different depths according to the second invention are electric blowers provided in the muffler portion with no partition between the concave portions. It becomes possible to provide the muffler with recesses having more different depths within the dimensions, and it is possible to reduce high-frequency sound having more different frequencies.

  According to a fourth aspect of the present invention, in particular, the silencer according to any one of the second to third aspects is an electric blower configured such that the depths of the plurality of short-width recesses are continuously changed. A wide frequency range that includes high-frequency sound without reducing the efficiency of the electric blower, since multiple sounds with different frequencies determined by all the depths from the minimum depth to the maximum depth of the recesses are muted by the resonance effect Can be reduced at once.

  In the fifth aspect of the invention, in particular, the silencer according to any one of the first to fourth aspects of the invention is an electric blower having a shape in which the chamfer is formed on the circumference of the entrance of the recess, so that the silencer at a high speed can be obtained. The disturbance of the air flow generated when passing through the recess inlet is reduced, so that the sound of the air flow generated due to the turbulence of the air flow can be reduced, and the silencing effect due to the resonance effect can also be obtained.

  According to a sixth aspect of the present invention, an impeller having a plurality of blades, an air guide having a plurality of stationary blades disposed around the air guide, and an air inlet having a central portion including the impeller and the air guide and having an air outlet on a side surface A fan case, an electric motor for rotationally driving the impeller, a soundproof cylinder having an exhaust port that covers the side surface of the fan case and the entire motor in a state of providing a gap, and a substantially axial direction of the rotating shaft of the impeller And a silencer having a branch path having a predetermined length arranged on the outer periphery, and the silencer is an electric blower provided on the side of the motor so that sound waves including high-frequency sound are soundproofed from the exhaust port of the fan case. When propagating through the air passage between the cylinder and the muffler, the sound of a specific frequency is divided into two at the branch path entrance of the muffler, and the sound passing through the branch path is in phase with the original sound. Interferes by a half wavelength shift Now cancel each other, it is possible to significantly reduce the high frequency sound.

  In the seventh aspect of the invention, in particular, by using the electric blower having the shape of the silencer of the sixth aspect having a plurality of and different lengths of branch paths, a plurality of sounds having different frequencies corresponding to the respective passage lengths can be obtained. After branching and passing through the branch path, they interfere with each other even if they are shifted by half a wavelength and cancel each other out, so that high-frequency sounds having a plurality of different frequencies can be reduced at a time.

  In the eighth aspect of the invention, in particular, the silencer of any one of the first to seventh aspects of the invention is an electric blower integrated with the side surface of the electric motor, so that the natural frequency of the motor and the silencer can be reduced. While suppressing the vibration of the high frequency area | region excited due to a difference, a number of parts can be reduced and a manufacturing process can be simplified.

  In the ninth aspect of the invention, in particular, by using a vacuum cleaner that uses the electric blower of any one of the first to eighth aspects, sound waves including high-frequency sound leaking from the exhaust port of the fan case are prevented from soundproofing cylinders and mufflers. When propagating through the air passage between parts, the sound of the specific frequency is greatly silenced by the resonance or interference effect at the silencer provided on the side of the motor, and low noise with less harsh high frequency sound The vacuum cleaner can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a cross-sectional view showing a configuration of an electric blower according to a first embodiment of the present invention, and FIG. 2 is a plan view of an impeller according to the same embodiment.

  In FIG. 1, an electric blower 1a includes a front shroud 2 made of sheet metal and an impeller 5 configured to sandwich seven blades 4 between a rear shroud 3 facing the front shroud 3 and twelve stationary blades arranged around the blade. 6, an air guide 7 including the impeller 5 and the air guide 7, a fan case 10 made of sheet metal having an intake port 8 in the center and an exhaust port 9 on the side surface, and an electric motor 11 that rotationally drives the impeller 5. And the soundproof cylinder 13 with the exhaust port 12 covering the side surface of the fan case 10 and the entire motor with a gap, and the depths of 19 mm and 4 mm toward the rotating shaft 14 of the impeller 5, respectively, and a width of 5 mm. The silencer 16a having the two recesses 15a on the circumference is provided on the side of the motor 11.

  The motor 11 includes a frame 18 including the stator 17 and a front bearing 21, the bracket 19 includes a rear bearing 22, and the rotary shaft 14 to which the rotor 20 is fixed is connected via the front bearing 21 and the rear bearing 22. It is supported. The impeller 5 is fixed to the tip of the rotating shaft 14, and power is supplied from the commutator 23 to the rotor 20. Further, the inner surface of the fan case 10 is in contact with the upper end of the stationary blade 6 and forms an independent volute chamber 24 between the adjacent stationary blades 6.

  About the electric blower comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, electric power is supplied from the commutator 23 to the rotor 20, the impeller 5 is rotated at a high speed by the electric motor 11, and the airflow A flows from the air inlet 8 of the fan case 10. The inflow air flow A is given kinetic energy from the blade 4 of the impeller 5 rotating at high speed, and is discharged from the outer periphery of the impeller 5. The discharged air flow B is decelerated while passing through the volute 24 chamber formed by the stationary blade 6 disposed in the air guide 7 to convert kinetic energy into static pressure, and a part of the air flow B is a fan case 10. The remaining airflow C is discharged from the side exhaust port 9, passes through the return passage on the back surface of the air guide 7, passes through the communication hole of the bracket 19, passes through the interior of the motor, and is discharged from the exhaust port 12 provided in the frame. Is done. Since the number of blades of the impeller 5 is limited, pressure pulsation occurs in the airflow passing through the inside, and the frequency of the pulsation is expressed by the product of the number of rotations per second of the impeller 5 and the number of blades 4 and the sound pressure that protrudes including its overtones. It is generated as a high frequency sound having a level.

  Since the generated sound wave including the high frequency sound can be propagated in all directions by being propagated in the air and in the solid, a great effect can be obtained by silencing near the sound source. Sound waves including high-frequency sound leaked from the exhaust port 9 on the side surface of the fan case 10 are propagated through the air passage between the soundproofing cylinder 13 and the silencer 16a toward the exhaust port 12 of the soundproofing cylinder 13 at the respective depths. Sounds of two different frequencies determined by the resonance with the respective short-width recesses 15a provided in the silencer 16a reduce the sound pressure level. When the width of the concave portion 15a is intended to reduce high frequency sound, a sufficient effect can be obtained at about 1/10 of the wavelength. By setting the width to a short width, the concave portion 15a is used as a resonance space, and the resonance frequency of the concave portion 15a is obtained. By setting the depth of the recess 15a so that the frequency of the high frequency sound generated by the impeller 5 becomes the frequency, the high frequency sound can be reduced.

  As described above, in the present embodiment, by using the electric blower provided with the silencer 16a having the two short-width concave portions 15a on the circumference on the side surface of the motor, high-frequency sounds having two different frequencies can be obtained. The sound pressure level can be reduced by resonating at the recess 15a.

  In this embodiment, the electric blower 1 having the silencer 16a provided with the partition between the two recesses 15a has been described. However, as shown in FIG. 3, the silencer without the partition provided between the recesses 15b. Even in the electric blower 1b having 16b, the same silencing effect can be obtained, and it becomes possible to provide short-width concave portions with more different depths within the limited dimensions in the silencing portion, and more different frequencies. High frequency sound can be reduced. That is, there are as many resonance frequencies as the number of recesses with different depths provided in the silencer, and the more the short recesses with different depths are provided, the more the sound with more frequencies can be reduced.

  As shown in FIG. 4, in the electric blower 1c having the silencer 16c in which the depth of the concave portion 15c continuously changes in the direction of the rotating shaft 14 of the impeller 5, each concave portion 15c has a minimum depth to a maximum depth. Since a plurality of sounds having different frequencies determined by all the depths are muted by the resonance effect, it is possible to reduce sounds in a wide frequency region including high-frequency sounds at a time.

  Furthermore, as shown in FIG. 5, in the electric blower 1d having the silencer 16d having a rounded chamfer on the inlet of the recess 15d on the circumference, it occurs when passing through the recess 15d inlet of the silencer at a high speed. The disturbance of the air flow is reduced, so that the airflow sound generated due to the disturbance of the airflow can be reduced, and the noise reduction effect due to the resonance effect can also be obtained.

(Embodiment 2)
FIG. 6 is a schematic diagram showing the configuration of the electric blower according to the second embodiment of the present invention. The first embodiment of the present invention is the same as the first embodiment except that a silencer 16e having a predetermined length in the direction of the impeller rotational axis is arranged on the side surface of the motor 11 with a branch path 25a arranged on the circumference. The same components are denoted by the same reference numerals, and detailed description thereof is omitted. The path length of the branch path 25a was set to be equal to the half wavelength of the high frequency sound generated by the impeller 5.

  About the electric blower comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, electric power is supplied from the commutator 23 to the rotor 20, and the impeller 5 rotates at high speed by the electric motor 11. Since the number of blades of the impeller 5 is limited, pressure pulsation occurs in the airflow passing through the inside, and the frequency of the pulsation is expressed by the product of the number of revolutions per second of the impeller 5 and the number of blades of 4 blades. It is generated as a high-frequency sound having a specified sound pressure level. When a sound wave including high-frequency sound leaked from the exhaust port 9 on the side of the fan case 10 propagates through the air passage between the soundproofing cylinder 13 and the silencer 16e toward the exhaust port 12 of the soundproofing cylinder 13, a certain specific frequency. Is branched into two at the entrance of the branch path 25a of the silencer 16e. Since the path length of the branch path 25a is equal to the half wavelength of the high frequency sound to be reduced, the phase of the sound that has passed through the branch path 25a is shifted by a half wavelength with respect to the original sound. For this reason, the two sounds interfere with each other and cancel each other, and the high-frequency sound can be greatly reduced.

  As described above, in the present embodiment, the silencer 16e in which the branch path 25a having a length equal to the half wavelength of the high-frequency sound is arranged on the circumference in the direction of the rotating shaft 14 of the impeller 5 is provided on the side surface of the motor 11. By using the electric blower 1e, the sound pressure level at which the high-frequency sound protrudes can be significantly reduced by causing interference with the original sound even if the wavelength of the specific high-frequency sound is shifted by a half wavelength in the branch path 25a.

  In this embodiment, the electric blower including the silencer 16e having only one branch path 25a having a predetermined length has been described. However, as shown in FIG. 7, a plurality of branch paths 25b having different lengths are provided. The electric blower 1f provided with a silencer 16f having a plurality of high-frequency sounds having different frequencies corresponding to the respective passage lengths may be shifted by half a wavelength after being branched and passed at the entrance of the branch path 25b. By interfering with each other and canceling each other, a plurality of high frequency sounds having different frequencies can be reduced at a time.

  Furthermore, in the case of an electric blower in which a silencer is integrally formed with a frame of an electric motor by injection molding of a heat-resistant resin, the high frequency excited due to the difference in the natural frequencies of the electric motor and the silencer. The vibration in the frequency domain can be suppressed, and the manufacturing process can be simplified by reducing the number of components and omitting the mounting process of the silencer.

(Embodiment 3)
FIG. 8 is a schematic diagram showing the configuration of a canister-type vacuum cleaner according to the third embodiment of the present invention.

  In FIG. 8, the vacuum cleaner 26 includes a vacuum cleaner main body 31 having a dust collection chamber 28 communicating with the main body intake port 27 and a blower chamber 30 having an exhaust port 29, and the main body intake port 27 and the airtightness in the dust collection chamber 28. A dust bag 32 attached to the air bag, an electric blower 1a installed in the blower chamber 30, a hose 33 airtightly connected to the main body inlet 27, the power on / off of the vacuum cleaner 26, suction force, etc. A gripping portion 34 having various switches for operating settings, a floor nozzle 35 for sucking dust from the surface to be cleaned, and a connecting pipe 36 for airtightly connecting the floor nozzle 35 and the gripping portion 34. Has been.

  About the vacuum cleaner comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  First, when the electric motor 11 is driven, the inside of the dust collecting chamber 28 is brought into a negative pressure state, and the floor nozzle 35 sucks the air flow D containing dust from the surface to be cleaned. The air flow D passes through the connecting pipe 36, the grip 34 and the air passage in the hose 33, reaches the main body inlet 27, and flows into the dust bag 32. Dust contained in the air flow D is filtered and collected in the dust bag 32. The clean air flow E separated from the dust is sucked into the electric blower 1a in the blower chamber 30, passes through the electric blower 1a, and is discharged from the main body exhaust port 29. The high frequency sound having a specific frequency generated in the electric blower 1a propagates in the air and in the solid from the sound source, but the specific high frequency sound leaked from the fan case 10 by the silencer 16a provided on the side surface of the motor 11 is greatly increased. It is reduced and hardly propagates to the outside of the vacuum cleaner 26, and the annoying high-frequency sound during operation of the vacuum cleaner 26 is greatly reduced.

  As described above, in the present embodiment, by installing the electric blower 1a of the present invention in the blower chamber 30 of the vacuum cleaner 26, sound waves including high-frequency sound leaking from the exhaust port 9 of the fan case 10 are prevented from being generated by the soundproof cylinder. When propagating through the air passage between the sound absorber 13 and the silencer 16a, the silencer 16a provided on the side surface of the electric motor 11 greatly attenuates the sound of a specific frequency due to the resonance effect. A low noise electric vacuum cleaner 26 can be provided.

  As described above, the electric blower according to the present invention can significantly reduce high-frequency sound having a protruding sound pressure level generated by the impeller near the sound source and realize low-noise driving sound. It can be applied to applications such as industrial vacuum cleaners and commercial vacuum cleaners.

Sectional drawing of the electric blower in the 1st Embodiment of this invention Main section of the electric blower Cross section of the electric blower Cross section of the electric blower Cross section of the electric blower Sectional drawing of the electric blower in the 2nd Embodiment of this invention Cross section of the electric blower Schematic side sectional view of a vacuum cleaner using an electric blower in a third embodiment of the present invention Sectional view of a conventional electric blower equipped with a silencer

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a-1f Electric blower 4 Blade 5 Impeller 6 Stator blade 7 Air guide 8 Intake port 9 Exhaust port 10 Fan case 11 Electric motor 12 Exhaust port 13 Soundproof cylinder 14 Rotating shaft 15a-15d Short recessed part 16a-16f Silencer 25a, 25b Branch 26 vacuum cleaner

Claims (9)

An impeller having a plurality of blades, an air guide having a plurality of stationary vanes arranged around the fan, and a fan case including the impeller and the air guide and having an air inlet at a central portion and an air outlet on a side surface; A motor that rotationally drives the impeller, a soundproof cylinder that has an exhaust port in a state where a gap is provided in a side surface of the fan case and the entire motor, and a short that has a depth in a substantially radial direction of the rotating shaft of the impeller. An electric blower comprising a silencer provided with a width concave portion in a circumferential shape, and the silencer provided on a side surface of the electric motor. The electric blower according to claim 1, wherein the silencer has a plurality of short recesses having different depths. The electric blower according to claim 2, wherein the plurality of short-width concave portions having different depths are provided in the muffler portion without having a partition between the concave portions. The electric blower according to any one of claims 2 to 3, wherein the silencer has a configuration in which the depth of the plurality of short-width concave portions is continuously changed. The electric silencer according to any one of claims 1 to 4, wherein the silencer has a chamfered circumference on the entrance of the recess. An impeller having a plurality of blades, an air guide having a plurality of stationary vanes arranged around the fan, and a fan case including the impeller and the air guide and having an air inlet at a central portion and an air outlet on a side surface; A motor that rotationally drives the impeller, a soundproof cylinder having an exhaust port that covers the side surface of the fan case and the entire motor in a state of providing a gap, and a predetermined length in a substantially axial direction of the rotating shaft of the impeller An electric blower comprising a silencer having a branch path disposed on an outer periphery thereof, wherein the silencer is provided on a side surface of the electric motor. The electric silencer according to claim 6, wherein the silencer has a plurality of branch paths having different lengths. The electric silencer according to any one of claims 1 to 7, wherein the silencer is configured integrally with the electric motor. The vacuum cleaner using the electric blower of any one of Claims 1-8.