JP4862608B2 - Electric blower and electric vacuum cleaner using the same - Google Patents

Description

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

  Conventionally, this type of electric blower has been widely used for household vacuum cleaners (see, for example, Patent Document 1).

As shown in FIG. 12, an impeller 39 having a plurality of blades 38 attached to a rotating shaft 37 of an electric motor 36, an air guide 40 for guiding an air flow generated by the impeller 39, and an intake port 41 at the center. A casing 42 containing the impeller 39 and the air guide 40 and a hard sound-insulating cylinder 43 covering the outer periphery of the electric motor 36 are provided, and the exhaust port 44 of the sound-insulating cylinder 43 is connected to the rotating shaft from the exhaust port 45 of the electric motor 36. A recess 46 having a specific depth is provided on the inner wall of the soundproof cylinder 43 while being provided at a position away from the direction.
JP 2001-165097 A

  However, in the above-described conventional configuration, the exhaust port 44 of the soundproof cylinder 43 must be arranged at a position away from the exhaust port 45 of the electric motor 36 in the direction of the rotation shaft 37, and the pressure loss increases and the efficiency of the electric blower increases. There was a problem that it would decrease. Moreover, if it is going to maintain the efficiency of an electric blower, it will be necessary to enlarge the flow path in the soundproof cylinder 43, the soundproof cylinder 43 will enlarge, and it is difficult to make the efficiency of an electric blower and the size of the soundproof cylinder 43 compatible. there were.

  The present invention solves the above-mentioned conventional problems, and a low noise electric blower capable of greatly muffing a target high frequency sound without reducing the efficiency of the electric blower with a compact soundproof cylinder, and an electric cleaning using the same The purpose is to provide a machine.

In order to solve the above-described conventional problems, an electric blower of the present invention includes an electric motor, an impeller fixed to a rotating shaft that is an output shaft of the electric motor, an air guide that forms a ventilation path in an outer peripheral portion of the impeller, and a side surface A fan case that covers the impeller and the air guide, a soundproof cylinder that covers the electric motor and the fan case, and has an exhaust port at the rear side of the motor, and a silencer provided on the side of the motor in the soundproof cylinder, The muffling means is provided with a concave portion having a predetermined depth toward the rotation axis on the circumference, and a cylindrical wall having substantially the same diameter is extended so as to cover the side surface of the electric motor .

As a result, the exhaust passage from the opening on the side surface of the fan case and the exhaust passage from the side surface of the motor are formed in a state separated by a cylindrical wall provided in the silencer,
The airflow discharged from the side of the fan case flows to the exhaust port of the soundproofing tube without being disturbed, and the soundproofing effect is improved by resonance in the recess without increasing the pressure loss of the exhaust flow path with a compact soundproofing tube. It is possible to greatly mute the sound of a specific frequency . Moreover, a cylindrical wall becomes a sound insulation wall with respect to the sound radiated | emitted from the motor side surface, and a noise level can be reduced.

  In addition, the vacuum cleaner using the electric blower of the present invention can greatly reduce annoying high frequency sound generated by the electric blower during operation in the soundproof cylinder, and can be used comfortably with low noise. It is.

  The electric blower of the present invention and the vacuum cleaner using the electric blower are soundproof cylinders having a compact silencing structure, and can significantly reduce the target high frequency sound without increasing the pressure loss of the exhaust passage.

The first invention includes an electric motor, an impeller fixed to a rotating shaft that is an output shaft of the electric motor, an air guide that forms a ventilation path in the outer peripheral portion of the impeller, and an impeller and an air guide that have an opening on a side surface. A fan case that covers the electric motor and the fan case, and a soundproof cylinder having an exhaust port at a rear side of the side surface, and a sound deadening means provided on a side surface of the electric motor in the soundproof cylinder, the sound deadening means having a predetermined direction toward the rotating shaft A concave portion having a depth is provided on the circumference, and an electric blower is formed by extending a cylindrical wall having substantially the same diameter so as to cover the side surface of the electric motor. As a result, the exhaust passage from the opening on the side surface of the fan case and the exhaust passage from the side surface of the motor are formed in a state of being separated by the cylindrical wall provided in the muffler, so that the air is discharged from the fan case side surface. The airflow will flow to the exhaust port of the soundproofing tube without being disturbed, the generation of secondary noise due to the airflow disturbance will be reduced, and the compact soundproofing tube will not increase the pressure loss in the exhaust flow path , It is possible to greatly mute the sound of a specific frequency by improving the silencing effect due to the resonance. Moreover, a cylindrical wall becomes a sound insulation wall with respect to the sound radiated | emitted from the motor side surface, and a noise level can be reduced.

In the second invention, in particular, in the first invention, since the silencer has a plurality of recesses having different depths, there are resonance frequencies corresponding to the number of recesses having different depths. The sound can be muted.

A third invention is, in particular, in the first inventions, the silencing means, by providing the one recess stepwise, it is possible to mute the sound of a plurality of frequencies in one recess.

In particular, in the fourth invention, in any one of the first to third inventions, the cylindrical wall is configured integrally with the silencing means, so that the cylindrical wall is configured integrally with the silencing means. As a result, there is no need to attach the cylindrical wall to the silencer, and the number of parts can be reduced and the manufacturing process can be simplified.

In the fifth aspect of the invention, in particular, by using the electric vacuum cleaner using the electric blower of any one of the first to fourth aspects, the annoying high-frequency sound generated by the electric blower during operation is greatly increased in the soundproof cylinder. Therefore, it is possible to provide a low-noise vacuum cleaner.

  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)
FIGS. 1-7 shows the structure of the electric blower in Embodiment 1 of this invention.

  1 and 2, an electric blower 1 a includes an electric motor 3 having a rotor 2 and a stator 30, an impeller 5 having the rotor 2 and fixed to a rotary shaft 4 that is an output shaft of the electric motor 3, and an impeller 5 is provided with a ventilation path 6 and a return path 32 formed on the outer periphery of the air guide 5 and an air guide 8 having twelve stationary blades 7. A fan case 10 having an inlet 31 at the center and an opening 9 on the side is provided to cover the impeller 5 and the air guide 8, and has a predetermined depth toward the rotating shaft 4 on the side of the motor 3. A silencer 12 having two concave portions 11a provided on the circumference is installed, and a soundproof cylinder 14 having an exhaust port 13 at the rear side of the side surface is installed to cover the motor 3 and the fan case 10.

  The impeller 5 is configured by sandwiching seven blades 17 between a front shroud 15 made of sheet metal and a rear shroud 16 facing the front shroud 15.

  Further, the silencer 12 is installed on the side surface of the electric motor 3 in the soundproof cylinder 14, and the two recesses 11a have a depth of 21 mm, 10.5 mm, and a width of 5 mm. The silencer 12 is provided with a cylindrical wall 18a extending substantially in the same diameter and covering a part of the side surface of the motor 3.

  The soundproofing cylinder 14 has a bottom and covers the whole of the electric motor 3, and an airflow from the opening 9 flows between the inner surface of the soundproofing cylinder 14 and the outer surface of the silencer 12 and the cylindrical wall 18 a. .

  Here, in FIG. 3, the vacuum cleaner 19 includes a vacuum cleaner main body 23 having a dust collection chamber 21 communicating with the main body intake port 25 and a blower chamber 22 having a main body exhaust port 20, and a main body intake air into the dust collection chamber 21. The dust bag 24 that is airtightly attached to the mouth 25, the electric blower 1 a installed in the air blowing chamber 25, the hose 26 that is airtightly connected to the main body air inlet 25, and the power on / off of the vacuum cleaner 19 From a gripping portion 27 having various switches for operating the setting of suction force and the like, a floor nozzle 28 for sucking dust from the floor surface, and a connecting pipe 29 that connects the floor nozzle 28 and the gripping portion 27 in an airtight manner It is configured.

  About the vacuum cleaner comprised as mentioned above, the operation | movement and an effect | action are demonstrated below based on FIGS. 1-3.

  First, in FIG. 1, when electric power is supplied, a magnetic field is generated in the stator 30 and the rotor 2, and the rotor 2 is rotated by electromagnetic force, so that the impeller 5 fixed to the rotating shaft 4 rotates at high speed. To do. When the impeller 5 rotates at a high speed, the inside of the dust collection chamber 21 in FIG. 3 is in a negative pressure state, and an airflow sucked into the dust collection chamber 21 is generated. The airflow A including dust sucked from the floor nozzle 28 passes through the connection pipe 29, the grip portion 27, and the hose 26, and flows into the dust collection bag 24 from the main body inlet 25. The clean airflow B from which dust is filtered and separated by the dust collection bag 24 is sucked into the electric blower 1a and flows into the impeller 5 from the air inlet 31 of the fan case 10 in FIG. As shown in FIG. 2, the inflow airflow C is given kinetic energy in the impeller 5 rotating at high speed, and decelerates the ventilation path 6 formed by the stationary blades 7 of the air guide 8 formed on the outer periphery. It passes while converting kinetic energy into static pressure. The airflow D that has passed through the ventilation path 6 in the air guide 8 changes direction in the return passage 32 on the outer periphery of the air guide 8 and flows into the electric motor 3 as shown in FIG. While cooling the child 30 and the carbon brush, it is discharged from the side surface of the electric motor 3. The remaining airflow E is discharged from the opening 9 on the side surface of the fan case 10. The airflows D and E discharged from the side surface of the electric motor 3 and the side surface of the fan case 10 flow out from the exhaust port 13 of the soundproof cylinder 14 and are discharged from the main body exhaust port 20 of FIG.

  Since the number N of blades of the impeller 5 is finite, pressure pulsation occurs in the airflow passing through the inside. The frequency of pulsation is represented by the product of the number of revolutions Z per second of the impeller 5 and the number N of blades, and is generated as a high-frequency sound having a high peak sound pressure level called NZ sound. In addition, the higher harmonics of 2NZ and 3NZ, which are overtones, are also generated and transmitted in all directions while propagating through the air and solids. It is very important to mute the soundproof cylinder 14.

  The opening 9 on the side surface of the fan case 10 is provided to improve the efficiency of the electric blower 1a. However, since the opening 9 is very close to the impeller 5 that is a high-frequency sound source, the peak of the sound pressure level of the high-frequency sound is increased. It is a cause. Since the exhaust wall from the opening 9 on the side surface of the fan case 10 and the exhaust channel from the side surface of the motor 3 are separated from each other by the cylindrical wall 18a provided to extend to the silencer 12, The air flow smoothly flows through the respective flow paths and the pressure loss does not increase, so that the silencing effect by the resonance in the recess 11a of the silencing means 12 is improved, and the two frequencies radiated from the side surface of the fan case 10 are improved. High frequency sound is greatly muted. Moreover, since the cylindrical wall 18a becomes a sound insulation wall with respect to the sound radiated from the side surface of the electric motor 3, the noise level can be reduced.

When high frequency sound is targeted for reduction, the width of the recess 11a is about 1/10 of the sound wavelength of the sound muting object, and a sufficient silencing effect due to resonance can be obtained. By setting the depth of the recess 11a so that the resonance frequency of the recess 11a is equal to the frequency of the NZ sound generated by the impeller 5 and its overtone, the high frequency sound can be greatly reduced as shown in FIG. it can. This is because the concave portion 11a serves as a side branch in the acoustic circuit. When the depth of the concave portion 11a is L [m], the sound is silenced with respect to the sound of the resonance frequency f [Hz] represented by the following formula. It is said to be effective.

f = c / 4L (c: speed of sound [m / s])
Moreover, since the frequency of the high frequency sound generated by the rotation speed of the impeller 5 varies depending on the operation mode of the vacuum cleaner and the amount of dust collected in the dust bag 24, the noise reduction frequency is set in consideration thereof. The target high frequency sound can be silenced by providing the silencer 12 with the recess 11a having such a depth that the resonance frequencies match.

  As described above, in the present embodiment, the silencer 12 having the recesses 11a having two different depths toward the rotating shaft 4 has a substantially identical diameter and a cylindrical shape covering a part of the side surface of the motor 3. By adopting a configuration in which the wall 18a is extended, the exhaust passage from the opening 9 on the side surface of the fan case 10 and the exhaust passage from the side surface of the motor 3 are separated by the cylindrical wall 18a provided in the silencer 12. It will be formed in the state which was done. As a result, the air flow smoothly flows through the respective flow paths, and the pressure loss is not increased, so that the silencing effect due to the resonance in the concave portion 11a of the silencing means 12 is improved and radiated from the opening 9 on the side surface of the fan case 10. In addition, it is possible to greatly mute high frequency sounds of two different frequencies.

  Moreover, since the cylindrical wall 18a becomes a sound insulation wall with respect to the sound radiated from the side surface of the electric motor 3, and the noise level can be reduced, a significant silencing effect can be obtained in the compact soundproofing cylinder 14, which is unpleasant. A low-noise electric vacuum cleaner 19 with low high-frequency sound can be obtained.

  Further, in the present embodiment, the electric blower 1a in which the silencer 12 is provided with the two recesses 11a has been described. However, the number of recesses is not limited to two, and the number of recesses having different depths is resonated. Since there is a frequency, the number of recesses may be determined from the number of high-frequency sounds to be muffled.

  In addition, as shown in FIG. 5, by providing one concave portion 11b in a step shape, it is possible to mute a plurality of frequencies with one concave portion 11b.

  Further, in the present embodiment, as shown in FIG. 6, a curved surface shape (R shape) 33 is provided on the inner side of the end portion of the cylindrical wall 18 b provided to extend to the silencer 12, so that the side surface of the electric motor 3 is provided. When the airflow D discharged from the air passes through the flow path formed by the cylindrical wall 18b and the rear wall of the soundproofing cylinder 14, the turbulence of the airflow is reduced by flowing along the curved surface shape 33, and the secondary noise is reduced. Occurrence can be suppressed.

  Further, in the present embodiment, as shown in FIG. 7, a 2 mm felt is provided on the inner surface of the soundproofing cylinder 14 so as to cover the exhaust passage formed between the rear wall of the soundproofing cylinder 14 and the cylindrical wall 18a. With the configuration in which the sound absorbing material 34a is arranged, a part of the sound is absorbed by the sound absorbing material 34a when sound radiated from the side surface of the fan case 10 and the side surface of the electric motor 3 propagates to the exhaust port 13 of the soundproofing cylinder 14. Thus, the noise level can be reduced.

  As the sound absorbing material 34a, in addition to felt, a porous type sound absorbing material using a porous material such as soft urethane, glass wool, and fiber material, a thin film vibration type sound absorbing material using a thin plate or a thin film, and a sound deadening effect due to resonance. There is a resonance type sound absorbing material that uses the material, but the porous sound absorbing material is very easy to handle because it is easy to process and can be obtained at low cost. In addition, products having various sound absorption characteristics depending on the material and fiber diameter are handled on the market, making it easy to select a sound absorbing material according to the frequency to be muffled and facilitating noise reduction design.

( Reference form 1 )
FIGS. 8-10 shows the structure of the electric blower in the reference form 1 of this invention. The same elements as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  In FIG. 8, the electric blower 1 e has a large-diameter portion 18 g in which an end portion of a cylindrical wall 18 c provided extending to the silencer 12 is enlarged in the outer peripheral direction. Specifically, the diameter is increased by 4 mm in the outer peripheral direction.

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

  First, an exhaust passage formed by the cylindrical wall 18c and the rear wall of the soundproof cylinder 14 by providing the large diameter portion 18g at the end of the cylindrical wall 18c provided to extend to the silencer 12. Since the length becomes longer and the airflow D discharged from the side surface of the electric motor 3 easily flows along the exhaust flow path, the large diameter portion 18g becomes a wall for isolation from the exhaust flow path from the side surface of the fan case 10, Collision between the airflow E discharged from the side surface of the fan case 10 and the airflow D discharged from the side surface of the motor 3 is suppressed, and generation of secondary noise is reduced.

As described above, in the present reference to the large diameter portion 18g is provided at an end portion of the wall 18c of the tubular, to isolate the exhaust passage of the exhaust passage and the motor 3 side from the fan case 10 side Thus, the generation of secondary noise due to the collision of airflow can be reduced.

Moreover, in this reference form, as shown in FIG. 9, the end diameter of the cylindrical wall 18d provided to extend to the silencer 12 is a curved shape (R shape) that increases in the outer circumferential direction. As a result, the direction change of the airflow E discharged from the side surface of the fan case 10 is performed along the curved surface of the cylindrical wall 18d, the bending loss is reduced, and the airflow D discharged from the side surface of the electric motor 3 becomes a curved surface. The secondary noise caused by the collision of the airflow D with the cylindrical wall 18d can be reduced.

Moreover, in this reference form, as shown in FIG. 10, by having a phase shape (R shape) 35 on the inner surface of the abutting portion between the silencer 12 and the cylindrical wall 18c, the motor 3 is discharged from the side surface. As a result, the turbulent airflow flows along the curved surface, and the turbulence of the airflow at the contact portion is suppressed, so that secondary noise can be reduced.

( Reference form 2 )
FIG. 11 shows a configuration of an electric blower according to Reference Embodiment 2 of the present invention. About the same element as Embodiment 1, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

In FIG. 11 , the electric blower 1 h is configured such that the thickness of the cylindrical wall 18 f provided extending to the silencer 12 is continuously increased toward the end in the outer circumferential direction, and the rear surface of the silencer 12 and the tubular shape The sound absorbing material 34b such as 3 mm felt is arranged on the inner surface of the wall 18f.

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

  First, by increasing the thickness of the cylindrical wall 18f provided extending to the silencer 12 in the outer circumferential direction continuously toward the end, the airflow E discharged from the side surface of the fan case 10 is cylindrical. Flowing along the wall 18f and gradually turning toward the outer peripheral direction, the bending loss of the airflow E can be reduced. In addition, since the sound radiated from the side surface of the motor 3 is partially absorbed by the sound absorbing material 34b disposed on the rear surface of the silencer 12 and the inner surface of the wall 18f, without increasing the pressure loss in the exhaust passage, The noise level can be reduced.

In the first embodiment, by integrating the silencer and the cylindrical wall, there is no need to attach the cylindrical wall to the silencer, and the number of parts can be reduced and the manufacturing process can be simplified. .

Further, the configuration is implementation of the first, is not limited thereto, but may be formed by combining as necessary.

  As described above, the electric blower and the vacuum cleaner using the electric blower according to the present invention are soundproof cylinders having a compact silencing structure, and greatly increase the target high frequency sound without increasing the pressure loss of the exhaust passage. Since it can be reduced, the electric blower can be applied to other devices as well as being suitable as a general household or commercial vacuum cleaner.

Sectional drawing which shows the structure of the electric blower in Embodiment 1 of this invention Plan sectional view showing the impeller and air guide of the electric blower Sectional drawing which shows the structure of the vacuum cleaner using the electric blower A graph showing the sound pressure level of the operation sound of a vacuum cleaner using the same electric blower Sectional drawing which shows the other example of the electric blower Sectional drawing which shows the other example different from FIG. 5 of the electric blower Sectional drawing which shows the further another example different from FIG. 5 of the same electric blower Sectional drawing which shows the structure of the electric blower in the reference form 1 of this invention Sectional drawing which shows the other example of the electric blower Sectional drawing which shows another example of the electric blower Sectional drawing which shows the structure of the electric blower in the reference form 2 of this invention Sectional view showing a conventional electric blower

DESCRIPTION OF SYMBOLS 1a-1h Electric blower 2 Rotor 3 Electric motor 4 Rotating shaft 5 Impeller 6 Ventilation path 8 Air guide 9 Opening part 10 Fan case 11a, 11b Recessed part 12 Silencer 13 Exhaust port 14 Soundproof cylinder 18a-18f Cylindrical wall 19 Electric cleaning Machine 33, 35 Curved surface shape 34a, 34b Sound absorbing material

Claims (5)

An electric motor, an impeller fixed to a rotating shaft that is an output shaft of the electric motor, an air guide that forms a ventilation path on an outer periphery of the impeller, a fan case that has an opening on a side surface and covers the impeller and the air guide, and the electric motor And a soundproof cylinder covering the fan case and having an exhaust port at the rear side of the side surface, and a sound deadening means provided on the side of the electric motor in the soundproof cylinder, the sound deadening means having a recess having a predetermined depth toward the rotating shaft. An electric blower which is provided on a circumference and extends so as to cover a side surface of the electric motor with a cylindrical wall having substantially the same diameter . The electric blower according to claim 1, wherein the silencer is provided with a plurality of recesses having different depths. The electric blower according to claim 1, wherein the silencing means is provided with one concave portion in a step shape. The electric blower according to any one of claims 1 to 3 , wherein the cylindrical wall is configured integrally with the silencer. The vacuum cleaner using the electric blower of any one of Claims 1-4 .

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