JP3216988B2 - Vacuum cleaner and electric blower for vacuum cleaner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The invention electric vacuum cleaner and an electric sweep <br/> suitable electric blower is it use the dividing machine about. BACKGROUND OF THE INVENTION

[0002]

As described in JP-A-59-74396 BACKGROUND OF THE INVENTION In electric blower for use in traditional household vacuum cleaner, the inlet portion of the impeller, looking at the side plate from the meridian plane plate The curve was a continuous curve from the outer peripheral side and had a larger radius than the inner diameter of the impeller.

[0003]

Although the exhaust gas described in Japanese Patent Application Laid-Open No. Sho 59-74396 can reduce the exhaust noise, the sound transmitted from the wall near the inlet of the rectifying cylinder tends to be relatively large. . Also, the noise generated by the electric blower
The component that passes through the wall of the dust collection chamber tends to be relatively large. At the entrance of the impeller, the fan casing
The cover and the side plate of the impeller were arranged almost vertically. This
Therefore, the flow flowing from the axial direction has a radius at the impeller inlet
When turning in the direction, the flow separates on the side plate side and
Cause loss. Also, the flow condition at the inlet of the impeller is poor.
The noise equal to the product of the number of blades and the number of revolutions of the impeller
It was easy to increase. Also, the impeller entrance and fan case
Overlap length is determined by the thickness of the side plate of the impeller
Therefore, it was difficult to reduce the leakage flow rate. Further
The leakage flow is almost perpendicular to the main flow at the electric blower inlet.
Therefore, the separation of the flow was promoted. Also the side
The plate was curved when viewed from the meridian, so the side plate and base
The main plate and side plate are easily deformed when caulking by attaching
And the runout of the impeller was likely to increase. Also feather
A gap occurs at the end face of the vane inside the wheel, causing loss due to leakage
Was easy to increase.

[0004] It is an object of the present invention to reduce the leakage flow rate of an electric blower.
An object of the present invention is to provide a vacuum cleaner having a high suction power with a reduction in flow and flow separation .

[0005]

According to the present invention, there is provided an electric blower for a vacuum cleaner , comprising:
When the impeller is seen on the meridian plane, the side plates that constitute the impeller
In addition to providing roundness at the inlet, the radius of roundness and the impeller
The ratio to the vane entrance width is set to 0.5 to 1.0. More round
So that the inner peripheral end is substantially parallel to the rotating shaft of the motor.
In the axial direction of the rotating shaft, the main plate forming the impeller is
Provide a cylindrical protrusion extending toward the opposite side
You. In addition, the suction port of the fan casing and the impeller
A bent portion that is substantially parallel to the rotation axis of the motive is provided. Further
The cylindrical protrusion is formed on the outer peripheral side of the bent portion.
Position the bent and protruding parts of the motor so that
Overlap in the axial direction of the rotating shaft. This allows
Increase the length of the overlap between the fan casing and side plate.
Can increase the friction loss to the leakage flow.
The leakage flow rate can be reduced. In addition, the flow is
To separate from the side plate when turning in and turning in the radial direction
It becomes hard.

Further, a caulking position on the innermost peripheral side with respect to the side plate of the vane.
Position on the outer circumference side from the starting point of the roundness,
When the impeller is viewed in the meridian plane with the mouth width almost the same
Of the side plate outside the caulking position
I do. As a result, a uniform force is applied to each caulking part.
The deformation of the side plate due to the force applied to the caulked part
Gap between the vane and the side plate
The leakage flow between the pressure surface and the suction surface of the compressor is suppressed. As described above, the flow separation can be reduced and the flow can be caused to flow into the blades of the impeller, so that the incident loss can be suppressed and the noise can be prevented from increasing.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention by FIGS. 1 to 10.

FIG . 1 is a cross-sectional view of a vacuum cleaner showing one embodiment of the present invention, FIG. 2 is a transverse cross-sectional view of FIG . 1 as viewed from a direction A, and FIG. 3 is a view of FIG. Longitudinal section,
Figure 4 is a cross-sectional view viewed 1 Oite B direction et Figure.

The cleaner body 1 comprises an upper case 2 and a lower case 3
A wheel mount 4 rotatably attached to the lower case 3 below the lower case 3, and a dust filter 5 in front of the lower case 3.
Openable dust collection chamber lid 32 and upper case 2 for replacing
Has a handle 70 for carrying it.
Inside the vacuum cleaner main body 1, as a driving source of the vacuum cleaner,
An electric blower room 8 having a built-in inverter-driven brushless electric blower 7 with good control responsiveness without mechanical brushes,
A dust collecting chamber 9 for storing the dust collecting filter 5, a cord reel 11 for winding a power cord 10 for supplying power, and an accessory storage chamber 13 for storing a suction port 12 for a shelf are provided.

The electric blower room 8 accommodates the electric blower case 1.
It is formed in a first case composed of 6,17. The side part 15 of the electric blower case 16 is formed in a substantially cylindrical shape,
The brushless electric blower 7 near the center of the opposite side of the fan
Is formed. The inner peripheral side of the support portion 14 a is formed as a part of the electric blower case 16 by a convex curved surface 14. The outer peripheral side of the support portion 14a is formed of a concave curved surface, and the inner peripheral portion of the side surface portion 15 holds the sound absorbing material 18 incorporated in the first case. On the other hand, the side surface of the electric blower case 17 is also formed in a substantially cylindrical shape, and an annular support portion 17b is formed on the intake side of the brushless electric blower 7. Support part 17b from side
Are formed by a convex curved surface, and an annular rib 17a for supporting the brushless electric blower 7 is formed inside the convex curved surface, and the sound absorbing material 18 is held by the inner peripheral side of the convex curved surface on the outer peripheral side of the rib 17a. ing.

The brushless electric blower 7 supports both sides of the brushless electric blower 7 in the electric blower room 8 via the vibration-proof rubber 36 and the vibration-proof rubber 37 so that the rotational vibration sound is not transmitted directly to the electric blower case 17. . Electric blower cases 16, 17
Are supported by the exhaust duct cover 22 and the partition plate 63 via the vibration isolating rubbers 68 and 69, respectively. With such a configuration, the rotational vibration noise generated by the brushless electric blower 7 can be effectively reduced. Further, the exhaust from the brushless electric blower 7 passes through two tail pipes 38 so that the noise level of the brushless electric blower 7 itself can be reduced.

As shown in FIG. 2 , the electric blower chamber 8 is connected to a ring-shaped exhaust duct chamber 19 in the lower case 3 by an exhaust pipe having a smooth curved surface. On the side, similarly to the electric blower 8, a sound absorbing material 20 is attached inside. In the exhaust part of the electric blower room 8, a throttle part 21 is formed integrally with the electric blower case 16 for optimally adjusting the amount of exhaust air and reducing exhaust noise. The lower part of the exhaust duct chamber 19 is composed of the lower case 3, and the upper part of the exhaust duct chamber 19 is composed of the exhaust duct cover 22. The wheel mount 4 is provided with four caster mounting portions 25 so as to be rotatable around the caster shaft 26 so that the casters 27 can rotate freely. ing. A bumper 28 for preventing damage to furniture and the like is attached to the outer periphery. A plurality of (usually three to four) wheels 29 are provided below the lower case 3 so that the lower case 3 can be rotated with a gap on the inner surface of the wheel base 4. . The gap space between the lower case 3 and the wheel base 4 is used as a dispersion exhaust chamber 30 for the exhaust flow discharged from the intermediate exhaust port 24, and the exhaust air is discharged to the outside through the exhaust port 76. You.

As shown in FIG. 3 , the dust collecting chamber 9 includes a substantially cylindrical dust case (second case) and a dust collecting cover 32 inside the dust collecting cover 6. Dust collection case 31
As shown in FIG. 3 , the side surface portion is formed of four outwardly convex curved surfaces having a large radius of curvature and four outwardly convex curved surfaces having a small radius of curvature connecting the curved surfaces. The brushless electric blower 7 has a conical tapered portion and an annular projection 78 in the direction of the brushless electric blower 7. The wall surface of the dust collecting case 31 is formed of aluminum on the outer periphery and two layers of plastic on the inner peripheral side. The dust collection lid 32 is provided with an intake hose attachment port 62a above the center of the dust collection lid 32, and the periphery of the attachment port 62a is formed by a convex curved surface.

The inside of the dust collecting chamber 9 has a high-performance filter, that is, a micro filter 33 capable of collecting dust of about 0.3 μm up to 99% or more, and a box-shaped filter case partially having a filter. 58, and the dust collection filter 5 housed inside. A confidential packing 34 is provided on the suction side outer periphery of the filter case 58, and seals the sucked air by making contact with the dust collection chamber lid 32 and the dust collection case 31. Further, a vibration isolating rubber 35 formed so as to cover the protrusion 78 is fitted to the protrusion 78 of the dust collecting case 31 and is brought into contact with the inner periphery of the annular support portion 17b of the electric blower case 17, Dust chamber 9
To prevent air leakage.

At the end of the brushless electric blower 7, a position detecting section 40 for detecting the number of rotations of the rotor 39 is provided. If fine dust enters this portion, the reliability of position detection is reduced. In the case of this embodiment, a micro filter 33 is arranged on the intake side of the brushless electric blower 7.
The entry of fine dust into the position detection unit 40 is prevented. A hose insertion port 41 for rotatably mounting and supporting a hose 62 is provided in the dust collection lid cover 6, and is airtight with the dust collection chamber lid 32 via an airtight packing (suction port) 42. In addition, an airtight packing (filter) attached to the dust collecting lid 32
At 43, the dust collecting chamber lid 32 and the contact plate portion 44 of the paper bag filter 5 are kept airtight.

Next, the electrical components will be described. Figure
5 shows an overall circuit diagram used in this embodiment to. Figure
In 5 , the AC voltage from the AC 100V power supply 44 is
After passing through a power factor improving section 47 composed of a condenser 45 and a reactor 46 and a nozzle filter 48, the rectifying circuit 4
The DC voltage 200 v is supplied to the inverter circuit 51 after being rectified at 9 and smoothed by the smoothing capacitor 50. The brushless electric blower 7 has a rotor 39 composed of a two-pole permanent magnet and a three-phase stator winding. The speed control of the brushless electric blower 7 includes a position detector 40 for detecting the rotation speed of the rotor 39 and a base driver 5 for driving a transistor of an inverter circuit 51.
2 and a microcomputer 53 that drives a base driver 52 based on the detection signal obtained from the position detection unit 40. The microcomputer 53 is housed in a control unit 54. The control unit 54 includes a start switch operated by an actual user,
It is connected to a hand operation circuit 55 including a switch and the like for operating a rotary brush (not shown) provided on a suction opening (not shown). In the brushless electric blower 7, the output torque of the motor is determined by the current flowing through the stator winding.
The output torque can be varied by changing the applied current. That is, by adjusting the applied current, the output torque of the motor can be continuously and arbitrarily changed. Further, the rotation speed can be freely changed by changing the drive frequency of the inverter.

Next, mounting of each electric component on the cleaner body 1 will be described. As the power factor improving capacitor 45 and the smoothing capacitor 50, cylindrical ones are applied . As shown in FIG. 2 , the terminal side is turned up and fixed in a metal case 57 with a tape 56 and housed. I have. The inverter circuit 51 is modularized and fixed directly to the dust collecting case 31. Here, the dust collection case 31 is a metal case, and the inside (the filter case 58 side) is subjected to electrical insulation processing using a plastic material. Further, since the inverter circuit 51 generates a large amount of heat due to internal loss and needs to be cooled, the dust collecting case 31 itself is used as a cooling fin. In other words, the dust collecting case 31 utilizes this cooling action because it is always cooled by the intake air. The reason why the inside of the dust collecting case 31 is electrically insulated is that the filter case 58 is detachably attached to the dust collecting case 31 for maintenance of the micro filter 33 and the like. Although 31 is electrically insulated temporarily, this is to double insulate it in case of emergency. The reactor 46 for power factor improvement is
Since the single unit is heavy, it is arranged on the rotating shaft 23 of the lower case 3 at the most stable and firmly supported position in the substantially central portion of the cleaner body 1 when viewed from the plane. The noise filter 48 and the rectifier circuit 49 are combined into a single board to form a current board 59, and a base driver 52 (which is formed as a board) is combined with the components on the board as shown in FIG. It is housed in a metal case 60. Here, the reason why the battery is housed in the metal case 60 is to control the generation of noise that causes radio interference. The control unit 54 including the microcomputer 53 is disposed above the dust collection chamber 8. The code reel 11 and the control unit 54
Are mounted on a partition plate 63, and the upper part is protected by a reel cover 64. On the reel cover 64 on the control unit 54 side,
An LED lighting type power indicator 67 for indicating the degree of suction force is provided.

Next, the flow of air in the vacuum cleaner described above will be described. In each figure, the air flow is indicated by white arrows. The suction airflow flows into the dust collection chamber 8 from the hose insertion port together with the dust, and after the dust is filtered by the dust collection filter 5 and the filter case 58, passes through the micro filter 33 of the filter case 58, and is about 0.3 μm. As shown in FIG. 8, after 99% or more of the fine dust is removed, the dust enters the brushless electric blower 7 through the protection ribs 71 provided on the electric blower case 17 for safety protection. The air discharged from the brushless electric blower 7 passes through the tail pipe 38, enters the electric blower room 8, is reduced in sound by the sound absorbing material 18 attached thereto, and is smoothly guided to the exhaust duct room 19. Here, as shown in FIG.
Numeral 8 is attached to the brushless electric blower 7 at two locations. From the vicinity of the exhaust outlet 72 of the electric blower room 8, a part of the exhaust gas is directly guided to the exhaust duct room 19, but other exhausts are clocked in the electric blower room 8. Sound is effectively absorbed by the sound absorbing material 18 in the form of flowing around. Since the air volume when directing a part of the exhaust air from the vicinity of the exhaust outlet 72 to the exhaust duct chamber 19 is determined by the performance of the brushless electric blower 7 and the volume of the electric blower chamber 8, the performance of the brushless electric blower 7 is high. When the amount of exhaust air is large, if the entire exhaust air is caused to flow clockwise, the exhaust air speed increases, and the sound absorbing material 18 may reduce the sound absorbing effect. In this case, a part of the exhaust gas is configured to be directly guided to the exhaust duct chamber 19,
It is preferable to lower the wind speed of the entire exhaust air to enhance the sound absorbing effect of the sound absorbing material 18 to lower the overall noise level. Further, even if the performance of the brushless electric blower 7 is high and the exhaust air velocity is high, if the volume of the electric blower chamber 8 is increased, the exhaust air can be made to have an appropriate air velocity. Thus, sound can be effectively absorbed by the sound absorbing material 18. However, at this time, the larger the volume of the electric blower chamber 8, the larger the size of the cleaner main body 1 and the lower the handleability. Therefore, the performance of the brushless electric blower 7 and the volume of the electric blower chamber 8 are reduced. It is preferable that a part of the exhaust air is led directly to the exhaust duct chamber 19 in consideration of the balance, and the air volume is appropriately determined. In order to realize this, the exhaust outlet 72 is provided with a throttle 21 formed integrally with the electric blower case 16, and by setting this height appropriately, the wind speed of the exhaust air guided to the exhaust duct chamber 19 is reduced. Can be adjusted optimally. The flow path from the electric blower room 8 to the exhaust duct room 19 is as shown by a two-dot chain line in FIG.
Exhaust flow path connecting portions 73 having relatively large radii of curvature formed in the electric blower cases 16 and 17 are configured to have a smooth flow path. Exhaust duct chamber 19 is lower case 3
6 and the exhaust duct cover 22 shown by a dotted line in FIG. 6 , the exhaust air flowing into the exhaust duct cover 22 goes around the lower case 3 along the annular guide rib 61, and the sound absorbing material (bottom surface) 2.
0, the sound is smoothly discharged to the intermediate exhaust port 24 by the guide portion 74 having a large radius of curvature formed by the exhaust duct cover 22 and the lower case 3, as shown in FIG. Then, it flows into the distributed exhaust chamber 30 of the wheel base 4. Here, the intermediate exhaust port 24 is provided with a rectifying net 75 made of a material such as a wire net, so that the exhaust flow can be smoothly guided to the distributed exhaust chamber 30. The exhaust gas is exhausted from the distributed exhaust chamber 30 to the outside along the space between the lower case 3 and the wheel base 4 through an exhaust port 76 provided on the entire circumference of the cleaner main body 1. The exhaust port 76 is provided on the entire circumference. As a result, the wind speed is low, and it is possible to minimize the dust on the floor surface.

As described above, since the case is formed with a curved surface, the following operations and effects are obtained.

First, transmission of noise from a wall surface will be described. Assuming that the transmission loss of the wall is TL, the sound pressure incident on the wall is Pi, and the sound pressure transmitted to the wall is Pt, the transmission loss TL of the wall is TL = 10 log [| Pi | ² / | Pt | ² ] It is expressed by 1).

Assuming that each frequency is ω, the density of air is ρ, the sound speed is c, and the impedance of the wall is Z (ω), the ratio of the incident sound pressure Pi to the transmitted sound pressure Pt is Pi / Pt = 1 + Z (ω) / (2ρc) (2)

The impedance Z (ω) of the wall is given by Z (ω) = 2r + jωm + Sp / jω, where rigidity Sp against the internal pressure of the wall, density per unit area (area density) of the wall is m, and damping of the wall is 2r. … (3) This rigidity Sp has been solved analytically in the case of a cylindrical shape and a sphere. When the Young's modulus of the material is E, the gravitational acceleration is g, the thickness of the wall is t, and the radius of curvature of the wall is R, Equations (4) and (5) respectively.

Sp = Egt / R ² (in the case of a cylinder) (4) Sp = 2Egt / R ² (in the case of a sphere) (5) Thus, in order to reduce the amount of noise transmitted from the wall, It can be seen that it is sufficient to increase the surface density of the wall or to configure the wall with a curved surface, reduce the radius of curvature, and increase the Young's modulus of the material. In the low frequency range, as is clear from the above equation, it is effective to configure the wall with a curved surface. In a vacuum cleaner, the largest noise is in the frequency band of 500 to 200 Hz. In order to solve this problem, it is effective to configure the wall surface with a curved surface in order to reduce this frequency band.

In the vacuum cleaner, the wall of the present embodiment has a plastic thickness of at most 2 mm to 3 mm. For this reason, a double wall is used to reduce transmitted sound, but since the distance between the two walls is at most 20 mm or less, a frequency band of 500 to 200 Hz is easily transmitted.
In the frequency band of 500 to 200 Hz, if there is a plane portion on the wall surface, the transmitted sound from that portion is large, and the whole noise is easily determined by the portion.

For this reason, in the present embodiment, the shape of the wall surface is curved, and the frequency band with the highest noise in a vacuum cleaner in the range of 500 to 200 Hz is reduced by the above-described operation. In addition, the vibration generated by the electric blower is damped by a vibration-proof rubber or an elastic body, so that a double vibration-proof effect is obtained.

In particular, in the case of the present embodiment, the inside of the support portion on the side opposite to the fan is formed into a spherical shape, the side surface is formed as a substantially cylindrical surface, and the fan side is formed as a convex surface on the outer peripheral side up to the support portion. Since each of them has a radius of curvature of less than 100 mm and is made of a plastic material having a thickness of 2 mm, the effect of the rigidity term appears on the transmission loss at a frequency of 1500 Hz or less, and the transmission at a frequency of 1500 Hz or less. Sound is greatly reduced.

[0027] Also, since the small part of the radius of curvature greater reduction effect of the transmitted sound, the relatively large transmitted sound in this embodiment is limited to the side surface portion.

In this embodiment, almost the entire surface of the dust collecting case 31 is made of a two-layer member of plastic and aluminum, and has a convex surface on the outer peripheral side. In particular, a 0.5 mm aluminum plate is used. Even if the maximum radius of curvature is increased to 300 mm, 2 kHz
At frequencies below z, the effect of the rigidity term appears on the transmission loss,
The transmitted sound at a frequency of 1500 Hz or less can be greatly reduced. In addition, since the rigidity of the aluminum portion is mainly used, the rigidity can be maintained even if the pressure in the dust collection chamber 9 is as low as −20 kPa or less, and the wall surface can be made lighter than in the past.

Although the present embodiment has been described with reference to aluminum and plastic, a two-layer member of another metal member and a plastic composite material may be used.

In this embodiment, the electric blower case is made of plastic. However, this case may be made of a composite of metal such as aluminum and a plastic, so that the transmitted sound can be further reduced. Is obtained.

Further, since the hose mounting port 62a of the dust collecting chamber lid 32 is mounted above the dust collecting chamber lid 32, dust collected inside the dust collecting filter when the dust collecting filter is replaced is hardly spilled. This also, the distance between the discharge jet and the wall surface of the hose 62 becomes shorter, the collision velocity of the jet on the wall is increased, Ru can increase the mortality of mites.

A projection is provided on the fan side of the dust collecting case 31.
An elastic body is provided inside the protrusion of the electric blower case 16.
To elastically support the first case and the second case.
This reduces the circumference of the support and reduces the amount of air leakage.
There is fruit. Further, the vibration from the electric blower 7 is
Since the sound propagates through the sexual body, the rotational vibration noise is reduced.

Further, the protrusion on the fan side of the dust collecting case 31 is
The electric blower case is made of anti-vibration rubber to cover
When the dust collecting case 31 is pushed into the 16 parts, the vibration isolating rubber
Air flow increased abnormally without displacement
Therefore, it is possible to prevent the vibration from being easily transmitted.

Further, since the exhaust duct is extended from the electric blower case 16 and has a substantially uniform cross-section and a sound absorbing material disposed inside, the noise from the exhaust port can be sufficiently reduced. Combined with the effect of reducing transmitted sound and vibration sound, the noise of the vacuum cleaner can be significantly reduced.

Since the sound absorbing material in the electric blower case 16 is held by the side surface portion of the electric blower case 16 and the concave side of the outer periphery of the supporting portion on the side opposite to the fan, and the annular rib and the convex side supporting the electric blower 7 on the fan side. There is no need to attach a sound absorbing material to the case, making the manufacture extremely simple.

Since the electric blower 7 is supported on the electric blower case 16 via the vibration-proof rubber, and the electric blower case 16 is supported on the cleaner main body via the vibration-proof rubber, vibration from the electric blower to the cleaner main body is provided. can be significantly reduced transfer rate, Ru can be significantly reduced rotational vibration sound.

Next, the electric blower 7 will be described with reference to FIGS.
This will be described with reference to FIG. FIG. 9 includes a partial cross section of the electric blower.
FIG. The electric blower is a blower 80 and a motor 79
It is composed of Of the housing 81 of the electric motor 79
Inside, a rotor 83 fixed to a rotating shaft 82 and both sides
And a stator 85 having coils 84a and 84b
Have been. A bearing holding part is provided at the center of the end face of the housing 81.
The bearing holding portion 81a has a rotating shaft 82a.
Is provided with a bearing 86a for supporting one end of the bearing 86a. Also,
An exhaust port 81b is formed on an end face of the housing 81.
You. End bracket on the opposite side of the end face of the housing 81
87 is provided.
A blower 80 and an electric motor 79 are connected.

The end bracket 87 is composed of a central bearing holding portion 87a and an outer flat portion 87b. The flat portion 87b has an air inlet 88 for introducing air from the blower 80 into the electric motor 79. Is formed. The bearing holding portion 87a is provided with a bearing 86b that supports the other end of the rotating shaft 82. A diffuser 89 is disposed on the end bracket 87, and a centrifugal impeller 90 is provided upstream of the diffuser 89.
Are fixed to the rotating shaft 82 by a nut 91. In the centrifugal impeller 90 and the diffuser 89, a suction port 93 is formed at the center of a fan casing 92 fixed to the outer periphery of the end bracket 87 by press fitting.

The diffuser 89 includes a plurality of diffuser vanes 96 formed on an outer peripheral extension of the centrifugal impeller 90.
And return guide vanes 95 formed on the back side thereof. The return guide vanes 95 together with the end bracket 87 form a return guide passage for guiding the airflow to the intake port 88.

Next, the operation of the electric blower shown in this embodiment will be described. By driving the electric motor 79, the impeller 9
0, as shown by the arrow in FIG.
After the air flows into the fan casing 92, the air flow is discharged from the impeller 90, passes between the diffuser vanes 96, the flow direction is changed at the outer periphery thereof, and further passes through the return guide passage. Housing 8 via 88
1 is introduced. The air flow introduced into the housing 81 cools the rotor 83 and passes through an air passage formed by the stator 85 and the inner surface of the housing 81, cools the coils 84 a and 84 b, and cools the coils 84 a and 84 b from the exhaust port 81 b on the outer periphery of the housing 81. It is discharged to the outside air.

FIG . 10 shows the shape of the centrifugal impeller 90.
The impeller 90 includes a plurality of vanes 96, a side plate 97, and a main plate 98. The vane 96 has three projections.
The holes are provided in the side plate 97 and the main plate 98 and fitted and caulked, and each is fixed. The outer surface of the side plate 97 has a straight meridional shape, and the inner side of the caulking 99 is formed to have a rounded portion 97b.
The radius of curvature of a is 0.7 of the vane inlet diameter. A bent portion 92 is provided on the inner diameter side of the fan casing 92.
a is provided, and a gap 100 is formed between the impeller 90 and the rounded portion 97 a.

The airflow entering through the suction port 93 is boosted by the impeller 90, but a part of the airflow exiting the impeller 90 is caused by the pressure difference between the inlet and the outlet of the impeller 90 and the impeller 90 and the fan casing. 92 and flows into the impeller 90 again. For this reason, the impeller 90 also works against this leakage flow, and if the leakage flow rate is large, the performance of the electric blower is greatly reduced.
Since the thickness is larger than the plate thickness of No. 7, the friction loss against the leakage flow can be increased, and the leakage flow rate can be reduced.

Further, the direction of the leakage flow is parallel to the axis, and the main flow is also parallel to the axis at this portion. Therefore, the leakage flow does not adversely affect the main flow, and the radius of curvature of the rounded portion is further reduced. Therefore, the main stream is less separated from the side plate 97.

As a result of a visualization experiment using a water flow with the same shape as that of the present embodiment and the Reynolds number of the flow, the flow is separated on the side plate side of the impeller in the shape shown in FIG. 11 as a conventional example . However, as shown in FIG. 12 , it was found that the flow adhered to the side plate when the ratio between the radius of the roundness and the width of the vane inlet was 0.5 as in the present embodiment. Thus, noise generated at the frequency of the product of the number of rotations and the number of blades can be reduced. Further, the incident loss of the impeller does not increase.

The side plate 97 is formed linearly from the outer periphery to the caulking 99 when viewed in the meridian plane, and the height of the vane 96 is almost the same at the entrance and the exit. For this reason, although the vanes 96 are curved in the circumferential direction, when the projections of the vanes 96 are swaged, a uniform force is applied to each swaged portion. For this reason, the deformation of the side plate 97 and the main plate 98 due to the force applied to the caulked portion is suppressed. For this reason, the vane 96 and the side plate 97
A gap between the pressure plate and the main plate 98 is less likely to be generated, and leakage flow between the pressure surface and the negative pressure surface of the vane 96 is suppressed. Also, the side plate 97
And the main plate 98 has less runout, so that imbalance is less likely to occur, and noise at the frequency of the rotation speed is reduced.

[0046] Another embodiment of the present invention will be described by partial cross-sectional view of the blower shown in FIG. 13.

The outer diameter side of the side plate 97 is linear in the meridional plane, has a round portion 97a from the inside of the caulking 99, and further has a cylindrical protrusion 97 in the axial direction from the tip of the roundness.
b is provided. A bent portion 101a is provided on the inner diameter side of the fan casing 101, and the impeller 90
A gap 100 is formed between the rounded portion 97a and the rounded portion 97a. Since the length of the gap 100 is significantly larger than the thickness of the side plate 97, the friction loss against the leakage flow can be further increased, the leakage flow rate can be significantly reduced, and the efficiency of the electric blower can be improved. Can be improved.

FIGS. 14 and 15 show the diffuser 89 with vanes viewed from the direction of the suction port 93 of the electric blower. The diffuser entrance angle β3 shown in FIG. 14 is 3 degrees, the throat width sw is 2.2 mm, and is 0.02 compared to the diffuser inner diameter. The radius of the rounded tip of the vane 94 is 0.5 mm. The airflow discharged from the impeller 90 is decelerated at the half-open portion of the diffuser 89 with vanes, and then further decelerated at the flow path sandwiched between the vanes. In the present embodiment, since the configuration is as described above, the discharge speed of the impeller can be increased, and the peripheral speed of the impeller is increased to about 0.8 times. This makes the impeller smaller. FIG. 1 shows the efficiency difference of the electric blower when the diffuser inlet angle β ₃ was changed by using the same impeller as that of the present embodiment .
6 is shown. The graph is based on the efficiency when the diffuser entrance angle β ₃ is 5 degrees. Diffuser entrance angle β ₃
Is less than 2 degrees, the length of the half-open portion is too long, the friction loss increases, and the efficiency decreases. When the diffuser inlet angle β ₃ is 3 degrees or more, the diffuser inlet angle β ₃ does not match the discharge flow angle, and the performance is reduced. As described above, when the diffuser entrance angle β ₃ is 2 degrees to 3 degrees, the diffuser entrance angle β ₃ is about 2% compared to the conventional 5 degrees.
Efficiency is high, and 1% efficiency is high even in the peripheral angles of 1 to 2 degrees and 3 to 4 degrees.

As described above, by setting the inlet angle of the diffuser with vanes to 1 to 4 degrees, the outlet flow angle of the impeller can be set to a small value of 1 to 4 degrees, so that the blade width of the impeller is reduced. Higher output can be achieved by increasing the absolute speed of the exit of the impeller. Further, it is possible to reduce the friction loss which accounts for most of the loss in the low specific speed type impeller. Further, the maximum efficiency point of the diffuser can be maintained at the air volume at the design point. Furthermore, since the outlet flow velocity of the impeller can be increased, the impeller can be made smaller and the blower can be made smaller (compact).

FIG. 17 shows the efficiency of the electric blower when the shortest distance (throat width sw) from the tip of the vane of the diffuser to the adjacent vane is changed. Throat width w
If s is less than 0.017 compared to the inner diameter of the diffuser inlet, the deceleration at the half-open portion is not enough, and the deceleration in the flow path sandwiched between the vanes becomes large, and the flow in this portion is separated and the efficiency is reduced. Is declining. Further, when the throat width sw is 0.025 or more as compared with the inner diameter of the diffuser, the deceleration at the half-open portion is too large, the flow is remarkably biased, and flows into the flow path sandwiched between the vanes, so that the efficiency decreases. I have. As in the present embodiment, the efficiency is high when the throat width sw is 0.02 compared to the inner diameter of the diffuser.

As described above, by setting the shortest distance from the tip of the vane of the diffuser to the adjacent vane as 0.017 to 0.025 in comparison with the inside diameter of the diffuser inlet,
The flow entering the diffuser is not accelerated abruptly at the throat portion, so that an increase in loss is suppressed. Also,
The surging occurrence area shifts to the low air volume side, and the operating range of the cleaner increases.

Also, since the flow angle of the airflow discharged from the impeller 18 is small, the flow angle of the airflow discharged from the impeller 90 is small, so that the airflow discharged from the impeller 90 enters the diffuser 89. As it passes through a long distance, the inside diameter of the diffuser can be reduced as shown in FIG.
The loss of the bladeless diffuser can be reduced. Further, since the relative speed at the exit of the impeller can be reduced, noise can be reduced.

FIG . 18 shows the ratio of the total area of the throat width to the actual area of the diffuser entrance (Z _vd · b ₃ · sw / π · D ₃ · b
_This shows the efficiency difference of the electric blower when ₃ · sin β ₃ ) is changed. If the ratio of the total area of the throat width to the actual area of the diffuser inlet is 1.75 or less, the number of vanes in the diffuser increases, so the throat width becomes narrow, causing surging at small air volumes and increasing pressure loss at large air volumes. And the operating range tends to be narrowed. The ratio of the total area of the throat width to the actual area of the diffuser entrance is 3.5.
In the above, there is a disadvantage that interference with the number of blades of the impeller is likely to occur due to a decrease in the number of vanes of the diffuser 89, a peak sound is generated, and a noise level is increased. The efficiency is high when the ratio of the total area of the throat width to the actual area of the diffuser entrance is 2.1 as in this embodiment.

As described above, by setting the ratio of the total area of the throat width to the actual area of the diffuser entrance from 1.75 to 3.5, the number of vanes and the throat width can be optimized, and the vanes of the diffuser can be optimized. Peak noise generated by interference between the number of blades and the number of blades of the impeller can be avoided.

FIG . 19 shows another configuration example of the diffuser . The diffuser forms a passage such that a part thereof overlaps with the diffuser. Round the tip of the vane 94,
A taper is provided at the distal end, and the throat width sw can be secured in an optimum range by this tapered shape. In the vicinity of the set air volume, the flow discharged from the impeller 90 flows along the vane 94. On the low air volume side, separation occurs on the negative pressure surface side of the diffuser vane at the half-open portion as shown by the arrow in the figure, but is adjacent. Since the direction of the flow is forcibly corrected by the tapered portion on the side of the pressure surface of the vane, the separated flow can be alleviated, so that the surging occurrence region can be further shifted to the lower air volume side.

[0056] Figure 20 is an experimental result showing the relationship between the air volume and pressure (static pressure) of the electric dynamic blower. The broken line shows the case where a conventional diffuser with a diffuser entrance angle of 5 degrees was used, and there was a surging occurrence area near the design point. However, in the example of 3 degrees shown by the solid line, the surging occurrence area was quite small in the air volume area. Can be migrated.

According to each of the above-described embodiments, firstly, the case for enclosing the electric blower or the case for enclosing the dust collection chamber is constituted by a curved surface, so that transmitted sound in a frequency band of 1500 Hz or less can be particularly reduced. This has the effect of reducing noise.

Further, by partially forming the wall material from a composite material of a metal such as aluminum and a plastic, the rigidity can be maintained and the transmitted sound in a low frequency band can be further reduced. Also, with the double case and double vibration isolation effect, the transmitted sound from the main body of the vacuum cleaner and the vibration sound can be reduced in a well-balanced manner. In addition, an extremely low-noise vacuum cleaner can be obtained.

Second, the vibration of the electric blower is transmitted to the second case by elastically supporting the connection between the first case covering the electric blower and the second case covering the dust chamber via an elastic body. Since the propagation can be reduced, the sound radiated from the second case can be reduced.

Further, since the sound absorbing material can be stably held in the exhaust passage in the case, the sound absorbing effect can be effectively exerted.

Further, by appropriately setting the height of the throttle formed in the blower case, the air volume distribution can be properly performed and the wind speed can be reduced, so that the effect of the sound absorbing material can be effectively exerted.

Fourth, the diffuser entrance angle β _{3 is set} to 1
Since the angle can be reduced from degrees to 4 degrees as compared with the related art, the exit flow angle of the impeller can be reduced and the exit speed can be increased. In addition, the output can be increased with the same size of the impeller. As a result, the outer diameter of the blower becomes the same, the compatibility with the conventional electric blower is maintained, the cost is advantageous, and the size of the electric blower is reduced.

Further, in order to obtain the same output, the size can be reduced and the number of rotations can be suppressed low. Thereby, noise can be reduced. Further, by setting the throat width sw from 0.017 to 0.025 compared to the inner diameter of the diffuser inlet, the efficiency at the specification point of the vacuum cleaner can be kept high. Also, by setting the ratio of the total area of the throat width to the actual area of the diffuser entrance from 1.75 to 3.5,
Interference between the number of diffuser vanes and the number of blades of the impeller can be avoided.

Fifth, since the separation of the inlet flow of the impeller of the electric blower can be prevented and the leakage flow rate can be reduced, the efficiency of the electric blower can be improved, and the number of blades and the number of rotations of the impeller can be improved. The noise of the product frequency can be reduced. Also,
Since the runout of the side plate and the main plate of the impeller is reduced, imbalance is less likely to occur, and noise at the frequency of the rotation speed can be reduced. Further, since the gap between the pressure surface and the negative pressure surface of the vane of the impeller is reduced, leakage flow from the end of the vane can be prevented, and the efficiency of the electric blower increases.

[0065]

According to the present invention, by reducing the separation of the inlet flow of the impeller of the electric blower, and it is possible to reduce the leak rate, Hakare higher efficiency of the electric blower, a suction
It is possible to provide a vacuum cleaner having a high work rate.

[Brief description of the drawings]

FIG. 1 is a sectional view of a vacuum cleaner showing one embodiment of the present invention.

FIG. 2 is a cross-sectional view as viewed from a direction A in FIG.

FIG. 3 is a vertical cross-sectional view as viewed from a dust collection case in a direction D in FIG.

FIG. 4 is a cross-sectional view as viewed from a direction B in FIG.

FIG. 5 is a drive circuit diagram for driving a brushless electric blower used in the present embodiment.

6 is a bottom view of FIG. 1 with the wheel base 4 removed and viewed from a direction C. FIG.

FIG. 7 is a sectional view taken along line EE in FIG. 6;

FIG. 8 is a front view of the electric blower case viewed from a direction F in FIG.

FIG. 9 is a front view including a partial cross section of the electric blower.

FIG. 10 is a vertical sectional view of a blower.

FIG. 11 is a diagram showing the flow of air as a result of a visualization experiment simulating the shape of a blower.

FIG. 12 is a diagram showing the flow of air as a result of a visualization experiment simulating the shape of a blower.

FIG. 13 is a longitudinal sectional view of a blower showing another embodiment of the present invention.

FIG. 14 is a plan view of the blower of the electric blower shown in FIG.

FIG. 15 is a plan view of the blower of the electric blower shown in FIG. 9;

FIG. 16 is a diagram showing performance results of the electric blower when the diffuser inlet angle is changed.

FIG. 17 is a diagram showing performance results of the electric blower when the ratio between the throat width and the inner diameter of the diffuser is changed.

FIG. 18 is a diagram showing performance results of the electric blower when the ratio between the front area of the throat width and the diffuser inlet area is changed.

FIG. 19 is a plan view of a blower showing another embodiment of the present invention.

FIG. 20 is a diagram showing aerodynamic performance results of the present embodiment.

[Explanation of symbols]

3 ... lower case, 4 ... wheel stand, 7 ... brushless electric blower, 8 ... electric blower room, 15 ... side part, 16, 17 ... electric blower case, 18 ... sound absorbing material, 19 ... exhaust duct room,
Reference Signs List 20: sound absorbing material (bottom surface), 21: throttle part, 22: exhaust duct cover, 24: intermediate exhaust port, 30: distributed exhaust chamber, 61
... Guide ribs, 72 ... Exhaust outlet, 73 ... Exhaust flow path connecting part,
74 guide unit, 76 exhaust port, 79 electric motor, 80 blower, 89 diffuser, 90 centrifugal impeller, 9
2 ... fan casing, 92a ... bent portion, 94 ... diffuser vane, 95 ... return guide blade, 97 ... side plate,
97a: rounded portion of side plate, 98: main plate, 99: caulked portion,
100: gap, β ₃ : entrance angle, sw: throat width.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masao Sunagawa 1-1-1, Higashitaga-cho, Hitachi City, Ibaraki Prefecture Inside the Taga Plant, Hitachi, Ltd. No. 1 Inside the Taga Plant of Hitachi, Ltd. (56) References JP-A-56-81297 (JP, A) JP-A-64-60799 (JP, A) JP-A-58-169426 (JP, A) 61-46496 (JP, A) JP-A-60-233394 (JP, A) JP-A-52-134114 (JP, A) JP-A-50-124208 (JP, A) JP-A-1-80697 (JP, A) U) Shokai 63-60098 (JP, U) Shokai 64-47999 (JP, U) Susumu Terada, “Design and Drafting of a Centrifugal Pump”, Riko Books Co., Ltd., April 15, 1969, Second edition, p. 115, p. 235

Claims (2)

(57) [Claims] 1. A motor fixed impeller with respect to the axis of rotation of, brewing covering the diffuser vanes and the return guide vanes and the impeller provided between said said impeller motor 該羽
Equipped with a fan casing formed with a suction port to the root wheel ,
The impeller is provided with a vane and an axial direction of the rotating shaft of the vane.
A side plate provided on the suction port side of the fan casing in a direction,
What is the side plate in the axial direction of the rotation shaft with respect to the vane?
An electric blower for a vacuum cleaner comprising a main plate provided on the opposite side , wherein an air flow inlet of the side plate when the impeller is viewed in a meridional plane.
Part is rounded, and the radius of the roundness and the impeller
The ratio to the vane inlet width is set to 0.5 to 1.0, and
So that the rounded inner peripheral end is substantially parallel to the rotation axis.
Extending in the axial direction of the rotating shaft toward the side opposite to the main plate.
A cylindrical protrusion is provided, at the suction port of the fan casing, at the impeller side,
A bent portion that is substantially parallel to the rotation axis is provided, and the cylindrical protrusion is positioned on the outer peripheral side of the bent portion.
So that the bent portion and the protruding portion
A caulking position on the innermost peripheral side of the vane of the impeller and the side plate which overlaps in the axial direction of the rotating shaft.
Is provided on the outer peripheral side from the starting point of the roundness.
With the inlet width and outlet width of the
When viewed in the meridian plane, outside the caulking position
An electric blower for a vacuum cleaner, wherein the side plate has a substantially straight shape . 2. A blade fixed to a rotating shaft of an electric motor.
Car, diffuser provided between the impeller and the electric motor
Blade and return guide vane and the impeller
Equipped with a fan casing formed with a suction port to the root wheel,
The impeller is provided with a vane and an axial direction of the rotating shaft of the vane.
A side plate provided on the suction port side of the fan casing in a direction,
What is the side plate in the axial direction of the rotation shaft with respect to the vane?
An electric blower including the main plate provided on the opposite side.
Therefore, the dust inside the main body is collected through the hose connected to the main body.
A vacuum cleaner that collects dust in a section , wherein the airflow inlet of the side plate when the impeller is viewed in a meridional plane.
Co The provision of rounded section, the round Mino radius of the impeller
The ratio to the vane inlet width is set to 0.5 to 1.0, and
So that the rounded inner peripheral end is substantially parallel to the rotation axis.
Extending in the axial direction of the rotating shaft toward the side opposite to the main plate.
A cylindrical protrusion is provided, at the suction port of the fan casing, at the impeller side,
A bent portion that is substantially parallel to the rotation axis is provided, and the cylindrical protrusion is positioned on the outer peripheral side of the bent portion.
So that the bent portion and the protruding portion
A caulking position on the innermost peripheral side of the vane of the impeller and the side plate so as to overlap in the axial direction of the rotating shaft.
Is provided on the outer peripheral side from the starting point of the roundness.
With the inlet width and outlet width of the
When viewed in the meridian plane, outside the caulking position
An electric vacuum cleaner characterized in that the side plate has a substantially straight shape .