JP2008036065A - Electric blower and vacuum cleaner using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-noise electric blower capable of suppressing the generation of an airflow sound in the operation by a compact silencing constitution and greatly reducing prominent high-frequency sound. <P>SOLUTION: This electric blower is provided with an impeller 5, an air guide 7 disposed in the circumference, a motor 9 driving a rotary shaft 8, a fan case 12 having a suction port 10 and an exhaust port 11 and fixed to the motor 9 wrapping the impeller 5 and the air guide 7, a soundproof tube 14 having an exhaust port 13 and wrapping the motor 9, a cylindrical silencing means 15a having a recessed portion 17a and provided in the side face of the motor 9, a cylindrical silencing means 16a having a recessed portion 18a and provided in the back face of the motor 9, and thin film portions 19a and 20a provided at the opening end faces of the recessed portions 17a and 18a. This constitution can suppress the generation of the airflow sound at the recessed portions 17a and 18a in the operation and greatly reduces the prominent high-frequency sound by the resonance effect. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

  Conventionally, this kind of electric blower and a vacuum cleaner using the same are well known (for example, refer to Patent Document 1).

As shown in FIG. 6, the fan case includes an impeller 41 having a plurality of blades, an air guide 42 having a plurality of stationary blades arranged in the periphery, and an air inlet 43 in the center. 44, an electric motor 45 that rotationally drives the impeller 41, and a soundproof cylinder 48 that covers the exhaust port 46 of the motor 45 and is provided with an exhaust port 47. A silencer 50 having a short cylindrical shape and an enlarged portion 49 that enlarges the cross-sectional area of the passage is provided.
JP 2001-32798 A

  However, the conventional configuration has a problem that when the airflow flows into the enlarged portion 49, the airflow collides with the side wall to generate a vortex, and the flow separation occurs to generate an airflow sound. . In addition, the exhaust port 47 of the soundproof cylinder 48 must be disposed in the center of the silencer 50, and a predetermined air path must be provided between the back surface of the motor 45 and the exhaust port 47 of the soundproof cylinder 48. When trying to maintain the efficiency of the electric blower 51, the air path becomes large, and as a result, the soundproof cylinder 48 becomes large.

  The present invention solves the above-described conventional problems, and provides a low-noise electric blower that can suppress the generation of airflow sound with a compact silencing structure and can significantly reduce the target high-frequency sound, and a vacuum cleaner using the same. The purpose is to provide.

  In order to solve the 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 a rotation in which the impeller is fixed. An electric motor that drives the shaft, and a substantially cylindrical fan case that is fixed to the electric motor in a state that includes an air inlet in the center of the front surface and an exhaust port in a side surface that encloses the impeller and an air guide. And a soundproof cylinder that is airtightly fixed to the fan case in a state of having an exhaust port and enclosing the entire motor, and a concave portion having a predetermined width and depth on the circumference, and a predetermined place on the surface of the motor And a thin film part having flexibility provided on the opening end face of the recess of the silencer.

  As a result, the airflow generated by the rotation of the impeller flows smoothly along the side surface of the silencer without flowing into the recess, and the generation of vortices and separation can be prevented and the airflow noise can be reduced. In addition, the sound pressure level is greatly reduced by resonating the sound of a specific frequency determined according to the depth of the concave portion through the thin film portion, and the electric blower is compact and low noise.

  Moreover, the electric vacuum cleaner using this electric blower is harsh because the high-frequency sound generated by the impeller during operation is greatly reduced by the resonance effect in the electric blower, and leakage of high-frequency sound from the vacuum cleaner body is suppressed. A low-noise electric vacuum cleaner with low high-frequency sound can be provided.

  The electric blower of the present invention and the electric vacuum cleaner using the electric blower can suppress the generation of airflow noise during operation with a compact silencing structure and can greatly reduce the protruding high-frequency 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 arranged around the impeller, an electric motor that drives a rotating shaft to which the impeller is fixed, and an air flow in the impeller A generally cylindrical fan case fixed to the motor in a state where the air inlet is provided in the center of the front surface and the air outlet is provided on the side surface and the impeller and the air guide are included, and the entire motor including the exhaust port. A soundproof cylinder that is airtightly fixed to the fan case in an encapsulated state, and a substantially cylindrical silencer that has a recess having a predetermined width and depth on the circumference and provided at a predetermined location on the surface of the motor; By making the electric blower provided with a flexible thin film portion provided on the opening end face of the concave portion of the silencer, the air flow generated by the rotation of the impeller does not flow into the concave portion along the side surface of the silencer. Now it flows in smoothly, it is possible to reduce the flow noise by preventing the occurrence of vortex and separation. In addition, the sound pressure level is greatly reduced by the sound having a specific frequency determined according to the depth of the recesses resonating through the thin film portion. In addition, since the recessed part is provided on the periphery, it can reduce high frequency sound with respect to all the sound waves which propagate toward the exhaust port of a soundproof cylinder irrespective of the propagation direction.

  According to a second aspect of the invention, in particular, in the first aspect of the invention, the silencer is provided on the side surface of the electric motor with substantially the same diameter as the fan case. Is made to resonate in the recess, so that the generation of airflow noise can be suppressed and the high frequency sound can be greatly reduced.

  According to a third aspect of the invention, in particular, in the first or second aspect of the invention, the sound deadening means is provided on the rear surface of the electric motor with substantially the same diameter as the electric motor, so that it propagates not only from the exhaust outlet of the fan case but also from the exhaust outlet of the electric motor. High frequency sound can be reduced by resonating sound with a specific frequency with respect to the sound wave, and the degree of freedom in design of the depth of the recess can be expanded, and the number of resonance frequencies set can be increased. Moreover, it becomes easy to set the resonance frequency according to the rotation speed of the electric motor.

  In the fourth invention, in particular, in any one of the first to third inventions, since the thin film portion is formed of an elastic material film or sheet, the material and thickness of the thin film portion can be widely selected. A thin film portion having suitable flexibility and heat resistance can be easily provided.

  According to a fifth aspect of the invention, in particular, in any one of the first to fourth aspects of the invention, the silencer has a plurality of recesses, so that the sound of a specific frequency resonates in each of the recesses. Can be greatly improved.

  According to a sixth aspect of the invention, in particular, in the fifth aspect of the invention, the silencer has a plurality of recesses having different depths, so that a sound having a specific frequency determined according to the depth of each recess resonates. Sounds with different resonance frequencies can be reduced at a time.

  According to a seventh aspect of the invention, in particular, in the fifth aspect of the invention, the sound deadening means has a concave portion with the same depth, so that the sound of the same specific frequency resonates in each concave portion, and the noise reduction effect is greatly improved. Can do.

  In the eighth invention, in particular, in the fifth invention, the silencing means eliminates the boundary wall between the concave portions and provides the concave portion, so that the wall thickness for the boundary wall becomes unnecessary, so the limited size It is possible to provide the silencing means with more concave portions having different depths, and it is possible to reduce the sound with more resonance frequencies.

  In the ninth aspect of the invention, in particular, by using the electric vacuum cleaner using the electric blower according to any one of the first to eighth aspects, the high-frequency sound generated by the impeller during operation is greatly increased by the resonance effect in the electric blower. Therefore, it is possible to provide a low-noise electric vacuum cleaner with less harsh high-frequency sound.

  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)
1 to 3 show an electric blower according to Embodiment 1 of the present invention.

  As shown in FIGS. 1 and 2, an electric blower 1 a according to the present embodiment includes an impeller 5 configured by sandwiching seven blades 4 between a front shroud 2 made of sheet metal and a rear shroud 3 facing the front shroud 3. , An air guide 7 having twelve stationary blades 6 disposed around the impeller 5, an electric motor 9 that drives a rotating shaft 8 with the impeller 5 fixed to the tip, and an air inlet that allows airflow to flow into the impeller 5. A substantially cylindrical fan case 12 fixed to the electric motor 9 with an exhaust port 11 on the side surface and an impeller 5 and an air guide 7 included in the front surface, and an exhaust port 13 on the rear surface. A soundproof cylinder 14 that is airtightly fixed to the front surface of the fan case 12 is provided in a state of including the entirety.

  Further, the side surface of the motor 9 is provided with a substantially cylindrical silencer 15a having the same diameter as the fan case 12, and the rear surface of the motor 9 is provided with a substantially cylindrical silencer 16a having the same diameter as the motor 9, respectively. The configuration is fixed. The silencer 15a has two recesses 17a having a depth of 10.5 mm and 7 mm and a width of 5 mm on the circumference, and the silencer 16a has a recess 18a having a depth of 21 mm and a width of 5 mm. A thin film portion 19a, 20a having flexibility, such as a silicon film having a thickness of 0.05 mm, is provided on the circumference, so that both the silencer 15a, 16a are substantially flush with the opening end surface of the recess. Each is provided and fixed to the recess with adhesive tape.

  In addition to the elastic material film such as silicon, the material used for the thin film portions 19a and 20a may be a resin material such as a rubber sheet or a polymer sheet, or a metal material such as an aluminum foil. What you have is used. The thickness of the thin film portion is desirably set as thin as possible while ensuring the strength to withstand the use environment in order to make the air flow smooth.

  Further, the electric motor 9 supports a rotating shaft 8 having a rotor 25 fixed to a frame 23 having a stator 21 and having an exhaust port 22 and a bracket 24 via a front bearing 26 and a rear bearing 27, and a commutator. Power is supplied from 28 to the rotor 25.

  The inner surface of the fan case 12 is in contact with the upper end of the stationary blade 6 and forms an independent volute chamber 29 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 28 to the rotor 25, the electric motor 9 is driven, and the impeller 5 rotates at high speed. Thus, the air flow C flows into the impeller 5 from the air inlet 10 of the fan case 12 by being sucked into the electric blower 1a. The inflow air flow C 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 D is decelerated while passing through the volute chamber 29 formed by the stationary blades 6 arranged in the air guide 7, and converts the kinetic energy into static pressure. A part of the air flow D flows out from the exhaust port 11 on the side surface of the fan case 12, smoothly passes through the air path between the silencer 15 a and the soundproof tube 14, and flows to the exhaust port 13 of the soundproof tube 14. At this time, since the thin film portion 19a is fixed to the opening end face of the concave portion 17a, the airflow does not flow into the concave portion 17a, and vortex generation and separation hardly occur. The remaining air flow passes through the return passage on the back surface of the air guide 7, passes through the communication hole of the bracket 24, passes through the inside of the electric motor 9, flows out from the exhaust port 22 provided in the frame 23, and is installed on the rear side of the electric motor 9. Then, the air flows between the sound deadening means 16a and the soundproofing cylinder 14 and flows out from the exhaust port 13 of the soundproofing cylinder 14. Also in this case, since the thin film portion 20a is fixed to the opening end face of the recess 18a, there is almost no vortex or separation in the recess, and the generation of airflow noise can be suppressed. An air flow E indicates an air flow flowing out from the exhaust port 13 of the soundproof cylinder 14.

  Here, since the number N of blades of the impeller 5 is finite, pressure pulsation is generated 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 of blades Z, and is generated as a high-frequency sound called NZ sound. In addition, high frequency sounds of 2NZ and 3NZ, which are overtones, are also generated and can be transmitted in all directions while propagating through air and solid. Therefore, in order to obtain a large silencing effect, the impeller that is a sound source is used. It is important to mute the soundproof cylinder 14 in the vicinity.

  In the silencer 15a installed on the side surface of the electric motor 9, two specific frequency sounds determined according to the depth of the respective concave portions 17a resonate, and high frequency sound propagated from the exhaust port 11 on the side surface of the fan case 12 passes through the concave portions. Is greatly reduced when On the other hand, in the muffling means 16a installed on the back of the motor 9, the sound of a specific frequency determined according to the depth of the recess 18a resonates, and the high frequency sound propagated from the fan case 12 and the exhaust port 22 of the motor 9 is greatly reduced. To do. When high frequency sound is targeted for reduction, a sufficient effect is obtained when the width of the concave portion is about 1/10 of the wavelength, and by making the width short, each concave portion becomes a resonance space, and the resonance frequency is generated in the impeller 5 NZ. By setting the depth of the recess so as to be equal to the frequency of the sound and its harmonics, the high frequency sound can be greatly reduced as shown in FIG. 3 (in addition, FIG. 3 shows the electric blower in the present embodiment) This is the sound pressure level of the operation sound of a vacuum cleaner using the

  This is because the recesses 17a and 18a serve as side branches in the acoustic circuit. When the depth of the recesses is L [m], the resonance frequency f [Hz] represented by the following equation It is said that there is a silencing effect.

f = c / 4L (c: speed of sound [m / s])
Further, since the maximum depth of the recess 18a that can be set by the silencer 16a on the side surface of the electric motor 9 is determined by the difference between the outer diameter of the fan case 12 and the outer diameter of the electric motor 9, the frequency band that can be silenced is limited. Therefore, a frequency band that is difficult to be silenced by the silencer 15a on the side of the motor 9 may be designed to be aimed at the silencer 16a on the back of the motor 9. This makes it possible to reduce high frequency sounds including NZ sounds and their harmonics. In addition, since the recessed parts 17a and 18a are provided on the circumference, it is possible to reduce high-frequency sound with respect to all sound waves propagating toward the exhaust port 13 of the soundproofing cylinder 14 regardless of the propagation direction.

  As described above, in the present embodiment, the NZ sound generated by the impeller and its overtone are resonated in the soundproof cylinder by using the electric blower provided with the sound deadening means having the thin film portions on the side surface and the back surface of the motor. Therefore, it is possible to obtain a low-noise electric vacuum cleaner that is greatly reduced and has few annoying high-frequency sounds.

  In addition, the silencer is provided on the side and back of the motor, reducing the high-frequency sound by resonating the sound of a specific frequency with the sound wave propagating from the exhaust port of the motor as well as the exhaust port of the fan case In addition, the degree of freedom in designing the depth of the recesses can be increased, and the set number of resonance frequencies can be increased. Moreover, it becomes easy to set the resonance frequency according to the rotation speed of the electric motor. The silencer may be only one of the side surface and the back surface of the motor as required.

  In addition, the silencing means has a plurality of recesses, so that a sound with a specific frequency can resonate in each recess, so that the silencing effect can be greatly improved, but the recesses have recesses with different depths. As a result, sounds having specific frequencies determined according to the depths of the respective recesses resonate, and a plurality of sounds having different resonance frequencies can be reduced at a time. Furthermore, since the concave portion has a concave portion having the same depth, the sound of the same specific frequency resonates in each concave portion, and the silencing effect can be greatly improved.

(Embodiment 2)
FIG. 4 shows an electric blower according to Embodiment 2 of the present invention. Since the basic configuration is the same as that of the first embodiment, the same elements are denoted by the same reference numerals and description thereof is omitted.

  The electric blower 1b in the present embodiment is different from that in the first embodiment in the configuration of the silencer. That is, the silencer 15b is provided with a recess by eliminating the boundary wall between the plurality of recesses 17b, and the silencer 16b is also provided with a recess without the boundary wall between the plurality of recesses 18b. Further, both of the silencers 15b and 16b are provided with thin film portions 19b and 20b on the opening end surfaces of the recesses 17b and 18b so as to be substantially flush with the opening end surfaces. Other configurations are the same as those of the first embodiment.

  As described above, in the present embodiment, by using the electric blower having the silencing means 15b and 16b in which no boundary wall is provided between the respective recesses, the same silencing effect as in the first embodiment can be obtained and limited. It becomes possible to provide the silencer with more recesses with different depths within the dimensions, and it is possible to reduce the sound of more resonance frequencies. That is, there are as many resonance frequencies as the number of recesses with different depths provided in the muffling means, and the more the recesses with different depths are provided, the more sounds with a higher frequency can be reduced.

(Embodiment 3)
FIG. 5 shows a vacuum cleaner according to Embodiment 3 of the present invention.

  As shown in the figure, the vacuum cleaner 30 includes a vacuum cleaner body 35 having a dust collection chamber 32 communicating with the main body intake port 31 and a blower chamber 34 having an exhaust port 33, and a main body intake port 31 in the dust collection chamber 32. A dust bag 36 that is airtightly mounted, the electric blower 1a of the first and second embodiments installed in the blower chamber 34, a hose 37 that is airtightly connected to the main body intake port 31, and a vacuum cleaner 30. A gripping portion 38 having various switches for operating settings such as power on / off and suction force, a floor nozzle 39 for sucking dust from the floor, and the floor nozzle 39 and the gripping portion 38 are connected in an airtight manner. It is comprised from the connecting pipe 40 for doing.

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

  First, the electric blower 1a is driven to be sucked into the electric blower 1a to bring the inside of the dust collection chamber 32 into a negative pressure state. As a result, the floor nozzle 39 sucks the air flow A containing dust, passes through the connection pipe 40, the grip 38 and the air passage in the hose 37, and flows into the dust bag 36 from the main body inlet 31. The clean air flow B separated from the dust in the dust bag 36 is sucked into the electric blower 1a installed in the blower chamber 34, and the air flow E is discharged from the exhaust port 33 of the cleaner body 35 to the outside of the cleaner. Is done.

  In the electric blower 1a, as described in the first and second embodiments, the sound deadening means 15a, 15b or 16a, 16b are provided. Therefore, the NZ sound generated by the impeller 5 of the electric blower 1a and its overtone are generated by the soundproof cylinder 14. The resonance effect is greatly reduced, and leakage of high-frequency sound from the cleaner body 35 is suppressed.

  Thus, by using the electric blower 1a in the first and second embodiments, as described above with reference to FIG. 3, it is possible to provide a low-noise electric vacuum cleaner with less annoying high-frequency sound.

  In addition, since the frequency of the generated high frequency sound varies depending on the rotation speed of the impeller of the electric blower according to the operation mode of the electric vacuum cleaner, it is desirable to set the resonance frequency in consideration of the operation mode.

  As described above, the electric blower according to the present invention and the electric vacuum cleaner using the electric blower can suppress the generation of airflow noise during operation with a compact silencing structure and can greatly reduce the protruding high-frequency sound. It can be applied to various devices as well as home and business vacuum cleaners.

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 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 structure of the electric blower in Embodiment 2 of this invention. Sectional drawing which shows the structure of the vacuum cleaner in Embodiment 3 of this invention. Cross section of a conventional electric blower

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Electric blower 4 Blade 5 Impeller 6 Stator blade 7 Air guide 8 Rotating shaft 9 Electric motor 10 Intake port 11 Exhaust port 12 Fan case 13 Exhaust port 14 Soundproof cylinder 15a, 15b, 16a, 16b Silencer 17a, 17b, 18a, 18b Recessed part 19a, 19b, 20a, 20b Thin film part 30 Vacuum cleaner

Claims (9)

An impeller having a plurality of blades; an air guide having a plurality of stationary blades arranged around the impeller; an electric motor that drives a rotating shaft to which the impeller is fixed; and an air inlet that allows airflow to flow into the impeller. A substantially cylindrical fan case fixed to the electric motor in a state of having an exhaust port on a side surface and including an impeller and an air guide, and a fan having an exhaust port and including the entire electric motor. A soundproof cylinder that is airtightly fixed to the case, a substantially cylindrical silencing means that has a recess having a predetermined width and depth on the circumference and is provided at a predetermined location on the surface of the electric motor, and a recess of the silencing means. The electric blower provided with the thin film part which has the softness | flexibility provided in the opening end surface. The electric blower according to claim 1, wherein the silencer is substantially the same diameter as the fan case and is provided on a side surface of the electric motor. The electric blower according to claim 1 or 2, wherein the silencer is substantially the same diameter as the electric motor and is provided on the back surface of the electric motor. The electric blower according to any one of claims 1 to 3, wherein the thin film portion is formed of an elastic material film or sheet. The electric blower according to any one of claims 1 to 4, wherein the silencer has a plurality of recesses. The electric blower according to claim 5, wherein the silencer has concave portions having different depths. The electric blower according to claim 5, wherein the silencer has concave portions having the same depth. The electric blower according to claim 5, wherein the silencing means is provided with a recess by eliminating a boundary wall between the recesses. The vacuum cleaner using the electric blower of any one of Claims 1-8.