JPH0759690A - Air turbine suck-up nozzle for vacuum cleaner - Google Patents

Abstract

PURPOSE:To obtain suppression of noise and rotation suitable for a floor quality by appropriately setting intervals of blades of an impeller and a height of a nozzle. CONSTITUTION:Blades 4a of an impeller 4 which is split into a plurality of parts are shifted from the another by half pitches, and the split surfaces are aligned with the center axis of a main nozzle 7 so that only one of blades 4a of each of the impeller part 4 is present within a height range of the main nozzle 7. Accordingly, generation of vortices due to turbulence between each adjacent blades may be reduced so as to restrain occurrence of noise. Auxiliary blades 4d of the blades 4a is off from the split surface as a center toward the side wall of the impeller 4, outside of the width (w) of the main nozzle, and accordingly, the auxiliary blades 4d do not disturb a set stream 8. A torque which is produced upon impingement of the jet stream against the impeller 4 is increased on the low speed side, and is decreased on the high speed side. Accordingly, a carpet floor with a heavy load may be cleaned powerfully, and a tatami (rush mat for Japanese domestic life) or a wooden floor with a low load may be softly cleaned at a speed which is lower than that of a conventional one, thereby it is possible to suitably cope with a quality of a floor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air turbine suction tool for an electric vacuum cleaner, and more particularly to a blade shape of an impeller.

[0002]

2. Description of the Related Art Due to the variety of lifestyle habits, the floor surface is a wide variety of floors, floors, tatami mats, and carpets.

In order to deal with these problems, a suction tool of an electric vacuum cleaner uses a motor or an aerodynamic air turbine as a power source for driving a rotary brush for cleaning a carpet.

The former must provide a power supply line to a hose, extension pipe, etc. connecting the cleaner body and the suction tool,
Since the suction tool has a built-in motor, it is heavy and has a large operating force, which is a burden on the user.

In the latter case, there is an increase in noise due to an increase in turbine rotation speed in an unloaded state such as when the suction tool is lifted.

Conventionally, a suction tool mounted on an air turbine is disclosed in, for example, Japanese Utility Model Laid-Open No. 53-97568 and Japanese Patent Laid-Open No. 63-19.
There is one disclosed in Japanese Patent No. 4619.

These suction tools utilize the suction airflow of the cleaner body, reduce the suction area by the nozzle, and make the suction air a high-speed jet airflow, and the impeller of the air turbine is rotated by this jet airflow.

Therefore, in order to secure this high-speed jet airflow, it is necessary to maintain the amount of suction air, so that the ventilation hole is not blocked by the sinking of the suction tool during cleaning of the carpet, and the large rotational force of the turbine. In order to obtain the above, a structure has been proposed in which plate bodies are provided close to each other on both sides of the turbine.

However, these structures do not take into consideration the noise generated when the high-speed jet stream collides with the impeller and the peripheral wall of the turbine chamber.

[0010]

The air turbine of the vacuum cleaner suction tool requires a large torque (rotational force) because it needs a rotational force to compensate for the resistance of the carpet and the loss of the timing belt between the air turbine and the rotary brush. ) Is required, for example, 0.12N ・ at a rotation speed of 10,000 r / min.
A torque of cm is required.

The torque of the air turbine is proportional to the product of the [jet flow rate] and the [jet flow velocity] of the nozzle.

The torque is determined by the resistance coefficient of a resistor such as a carpet or tatami mat when the rotary brush rotates.

The blown air volume is influenced by the blower performance of the cleaner body. Generally, the microcomputer in the cleaner body has 1.2 to 1 so that the blower operates with the air volume that increases the suction work of the blower. It is controlled at 0.4 m ³ / min.

Therefore, in order for the air turbine to output the required torque in the [blowing amount] of these nozzles, the [blowing velocity] of the nozzle hole is about 100 m / s.
It requires a high speed jet stream.

The maximum suction air volume due to the blower performance of the cleaner body is about 1.8 m ³ / min, but for example, in order to clean a carpet floor with a strong suction air volume, the vacuum cleaner is used with this maximum air volume. And the amount of air flow controlled by a commonly used microcomputer is 1.2 to 1.4 m ³ / min, the torque of the air turbine can be sufficiently obtained, but there is a drawback that noise is significantly increased.

The main noise of the air turbine mounted suction device is
The jet noise from the nozzle, the collision noise when the jet airflow collides with the blade, the collision noise generated when the airflow directly flowing from the nozzle and the flow passing through the impeller collide with each other, and the airflow directly flowing out from the nozzle All of the collision noises such as collision noises on the surrounding wall surfaces are caused by the large [jet velocity].

These influence each other, and the noise level is almost the same level.

When the sound of collision with the wall surface is loud, the noise of the suction tool also becomes loud. To reduce the collision noise, it is sufficient to slow down the jet air velocity of the nozzle, but the generated torque also becomes smaller,
There is a problem that the rotating force of the rotary brush loses the resistance of the carpet or the like and it does not rotate. Therefore, it is necessary to generate the jet airflow at a required flow velocity.

On the other hand, in order to downsize the air turbine suction tool, it is necessary to reduce the outer diameter of the turbine impeller and the area of the nozzle opening. However, this significantly increases the number of revolutions under no load, and the suction airflow The noise caused by the collision noise between the jet sound and the blade becomes extremely large.

From the above, there is a drawback in that the noise of the suction tool is large in the conventional flow path constituted by the nozzle, the impeller, the turbine chamber, the receiving port of the rotary joint, and the like.

Another drawback of the air turbine suction tool is that the rotational speed fluctuates greatly depending on the load condition of the floor surface, which is remarkable when the diameter of the turbine impeller is reduced.

According to the present invention, in order to solve the drawback of the large noise of the air turbine, the torque required to rotate the rotary brush is secured, the airflow collision of the air turbine is reduced, and the rotation speed due to the load on the floor is reduced. The object is to provide a suction device with little fluctuation.

[0023]

[Means for Solving the Problems] The noise caused by the jet airflow of the nozzle and the turbine impeller are a collision noise and a blade noise (wind noise).

Since the collision noise depends on the relative velocity difference between the colliding objects, it is preferable to reduce the flow velocity of the jet stream or the rotation speed of the impeller.

Since the blade noise depends on the number of collisions with the air flow,
It is better to reduce the number of blades.

If the discharge airflow velocity of the nozzle is the same, the no-load rotational speed of the air turbine impeller is almost determined by the outer diameter of the impeller, regardless of the number of blades, and the starting torque when the shaft is restrained is also the same. is there.

According to the present invention, auxiliary blades are provided on the blades on both side walls of the impeller divided into a plurality of parts, and these blades are shifted by a half pitch so that the divided surface of the impeller and the central axis of the nozzle coincide with each other.

Further, the blade interval on the outer circumference of the impeller is set to be equal to or slightly larger than the height of the nozzle, and each blade of the divided impeller exists only in the height region of the nozzle. To

[0029]

[Operation] The suction airflow narrowed down by the nozzle is 1
A high-speed jet stream of about 00 m / s is generated, which collides with the divided blades of the impeller and decelerates. This amount of deceleration converts the vortex due to the generation of torque and the turbulence of the flow into noise.

A part of the air flow that collides with the blade of the impeller flows back to the nozzle side.

When a large number of blades are present in the height region of the nozzle, the number of collisions at the outermost periphery of the turbine impeller increases, the averaged collision noise becomes louder, and the blade noise becomes higher.

However, if only one blade is present in the height region of the nozzle, the jet stream impinging on the outermost peripheral portion of the impeller having the highest peripheral speed will be minimized, and the inner angle will be increased due to the turning angle of the blade. Then, the collision position changes, and the jet flow collides with the inner diameter of the impeller having the lowest peripheral speed, that is, the innermost of the blades.

Therefore, as a result, the rotational speed of the turbine impeller is artificially reduced, and the collision noise is reduced. The blade sound is also shifted to the low frequency side.

The blades of the impeller are divided into two parts, and auxiliary blades are provided on the outer peripheral surfaces on the side walls of the two blades which are alternately staggered. One blade is provided in the height region of this auxiliary blade and the nozzle.
With the configuration in which there is only one, the jet airflow flowing from the nozzle can be effectively utilized.

Since there is only one blade in the nozzle region, the jet airflow that collides with this blade can suppress the generation of vortex between the blades that disturb the flow of the jet airflow that collides with the front and rear blades.

Most of the airflow that collides with the blade diffuses in the axial direction of the impeller and flows out in the direction opposite to the jet airflow of the nozzle, but there are auxiliary blades on the outer peripheral surfaces of both side walls of the impeller. Therefore, it collides with this auxiliary blade to generate a rotational force, decelerates and flows out.

Therefore, the work of the air turbine impeller, that is, the torque is increased as compared with the conventional case.

As described above, since the torque of the air turbine impeller increases, the "jet velocity" is decelerated by expanding the area of the nozzle outlet by the increase in torque even if the "air flow rate" is about the same as the conventional one. As a result, the noise of the air turbine can be significantly reduced.

According to the experiment, the rotational speed-torque characteristics of the air turbine when the discharge airflow velocity of the nozzle is the same, the shaft restraint torque and the no-load rotational speed are almost constant regardless of the number of blades, and the number of blades is small. Then, it was found that the decrease in the torque generated on the high-speed rotation side becomes large. This characteristic is used to suppress the rotation fluctuation due to the load condition of the floor surface.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a perspective view of a suction tool equipped with an air turbine according to the present invention, FIG. 2 is a sectional view taken along a plane parallel to the floor surface to be cleaned of FIG. 1, and FIG. 3 is a rotation of the impeller of FIG. Sectional view of XX 'perpendicular to the axis, Fig. 4 is a perspective view of only the impeller,
FIG. 5 is an explanatory diagram showing the positional relationship between the blades of the impeller and the nozzles, and FIG. 6 is an explanatory diagram showing the results of comparative experiments between the configuration according to the present invention and the conventional example.

The suction tool body is composed of an upper case 1 and a lower case 2, and has a rotary brush 3, an air turbine impeller 4, a shutter opening / closing mechanism 5 and the like built therein.

The high-speed jet airflow 8 narrowed down by the main nozzle 7 provided on the nozzle mounting plate 6 collides with the blade 4a of the impeller 4 which is divided into two parts, is decelerated to become the discharge airflow 9, and is cleaned. It is sucked into the blower (not shown) of the machine body.

The speed difference between the high-speed jet airflow 8 and the discharge airflow 9 becomes the rotational force, that is, the generated torque, and the power is transmitted to the shaft 10, the pulley 11, the timing belt 12 and the rotary brush 3.

The shaft 10 is a ball bearing bearing 13.
Is supported by a bearing holder 14 having a built-in bearing.

At the rear part of the suction tool body, a rotary joint 1 connected to a hose / extension pipe (not shown) connected to the cleaner body.
5 and is sandwiched between the upper case 1 and the lower case 2 so as to be slidably rotatable.

The turbine chamber 16 has an upper case 1 and a lower case 2.
It is formed by the nozzle support plate 6, which is sandwiched between the upper case 1 and the lower case 2, and the left and right side walls 17 and 18, and the rear wall 19.

A main nozzle 7 and a bypass nozzle 20 are arranged on the nozzle support plate 6, and both have a circular or elliptical shape.

The main nozzle 7 is used when the load of the carpet or the like is large, and the bypass nozzle 20 is operated by opening and closing the shutter 5a by the knob 5b of the shutter opening / closing mechanism 5 when the load of the tatami mat / wood floor is light. Used with 7.

Opening area of bypass nozzle 20 180 mm
² , the main nozzle 7 is 250 mm ^2, which is set smaller than the main nozzle 7, but this is set depending on the load condition of the floor surface and the application.

The central axis of the main nozzle 7 is the turbine impeller 4
It corresponds to the division plane of.

The lower end of the main nozzle 7 is arranged so as to substantially coincide with the outermost periphery of the impeller 4 on the bottom surface side of the lower case 2.

The bypass nozzle 20 is arranged so that the jet airflow 8 does not collide with the blade 4a of the impeller 4.

The air turbine impeller 4 is divided into two parts, a blade L4b and a blade R4c, and the respective blades 4a are displaced from each other by a half pitch. For example, 8 blades have a pitch of 22.5 ° and 4 blades have a pitch of 45 °. The inner / outer diameter ratio of the impeller 4 and the curvatures R on both sides are optimized.
The interval Y at the outermost periphery of the blade 4a of the impeller 4 is set to be equal to or higher than the height h of the main nozzle 7. Since the opening area of the main nozzle 7 is 250 mm ² , the diameter is 17.8 mm in the case of a circular cross section.
If the outer diameter is φ40, the number of blades is set to 7 or less. If the main nozzle 7 is elliptical, the height h of the main nozzle 7 can be arbitrarily set to some extent, so the degree of freedom in selecting the number of blades is increased, but the width w of the main nozzle 7 and the width of the impeller 4 are about 1: 3. Since it is proper, it is naturally decided.

An auxiliary blade 4d is provided on the side wall of the blade 4a of the impeller 4.

In the axial direction of the auxiliary blade 4d, the auxiliary blade 4d extends from the position equal to or larger than the width w of the main nozzle 7 to the side wall around the divided surface of the impeller 4, and also in the front and rear in the radial direction. Rear blade 4a up to about half the position of blade 4a
It is extended to the side.

The impeller 4 is fastened by a push-on fix 21 so as to be integrated with the shaft 10.

The shaft 10 is supported by a ball bearing bearing 13 held by a bearing holder 14 so that it can smoothly rotate.

A pulley 11 for rotating the rotary brush 3 via a timing belt 12 is fixed to the other end of the shaft 10.

The opening / closing of the bypass nozzle 20 is performed by the shutter 5a of the shutter opening / closing mechanism 5.

The bypass nozzle 20 is opened when cleaning a relatively lightly loaded floor surface such as a tatami mat or a wooden floor.

When cleaning a heavily loaded floor such as a carpet, the bypass nozzle 20 is closed by the shutter 5a of the shutter opening / closing mechanism 5.

An example of cleaning a heavy load floor such as a carpet with the above configuration will be described.

The suction air 23 flowing into the rotary brush chamber 22 is narrowed down by the main nozzle 7, becomes a high-speed jet stream 8, and collides with the blade 4a of the air turbine impeller 4.

Then, the speed difference with the discharge airflow 9 after the collision acts as momentum to generate a rotational force (torque). With this torque, the rotary brush 3 is rotated via the shaft 10, the pulley 11, and the timing belt 12.

Further, the auxiliary jet 4d prevents the diffused jet airflow 8a after the collision from colliding with the nozzle mounting plate 6, is straightened by the blade 4a and converges along the arc of the side wall 4e of the impeller 4. , And is discharged to the rotary joint 15 through a gap 24 between the impeller 4 and the bottom surface of the lower case 2.

Most of the discharge airflow 9 is sucked into the rotary joint 15 and a part of the airflow 8a diffused by the impeller 4 hits the rear wall 19 of the turbine chamber 16. Since it has a streamlined shape formed by an arc having a large curvature, it is quickly sucked.

Therefore, the generation of vortices due to the air flow after the collision is small, and the noise is reduced.

This will be described in more detail with reference to FIGS. 4, 5 and 6.

Since the distance between the outermost circumferences of the blades 4a of the impeller 4 is larger than the height h region of the main nozzle 7,
In this height region, there is only one blade 4a in each of the blades L4b and R4c divided into two, and the jet airflow 8 is not disturbed by the other blades 4a in front and behind, so that each blade 4a Turbulence is unlikely to occur between

The auxiliary blade 4d of the blade 4a is arranged closer to the side wall of the impeller 4 than the width w of the main nozzle 7 with the divided surface of the impeller 4 as the center. Do not disturb.

On the contrary, the jet airflow 8 colliding with the blades 4a and the inner circumference of the impeller 4 is decelerated, and in the impeller 4,
Diffuses outside the projection area of the opening of the main nozzle 7.

A part of the diffusion jet air flow 8a collides with the auxiliary blade 4d and acts so as to generate a rotational force.

Then, the rear blade 4a and the auxiliary blade 4d
Is rectified from the gap on the side wall side of and flows out of the impeller 4.
This effect is remarkable when the impeller 4 rotates at a low speed under a heavy load. This is because the jet airflow 8 can be sufficiently received between the blades 4a, and the effect of collision of the diffusion jet airflow 8a with the auxiliary blade 4d can be enhanced.

FIG. 6 is an explanatory diagram based on an experiment.

The experimental conditions are the outer diameter φ40 and the inner diameter φ of the impeller 4.
It is 15.

The main nozzle 7 is elliptical and has a short circle diameter of 16 mm, a long circle diameter of 22 mm, an opening area of 250 mm ² , and a suction air volume of 1.4 m ³ / min of the cleaner body.

When the number of blades Z = 8, the outer circumferential distance between the blades 4a is 15.7 mm, which is smaller than the height h16 mm of the main nozzle 7.

Therefore, the height area of the main nozzle 7 is 2
There will be one blade 4a.

When the number of blades Z = 4, the no-load rotation speed and the restraint torque are almost the same, but the torque decreases during that time.

When the number of blades is set to 5, 6, or 7, it shows the characteristic of approaching from 4 to 8.

The air turbine suction tool is characterized in that the rotation speed of the impeller 4 changes depending on the load state of the surface to be cleaned.

For a heavy load carpet floor and a light load wooden floor, 1
There is a torque difference of about / 10. Therefore, as described above, the bypass nozzle 20 is provided so as to obtain the impeller rotation speed adapted to the wooden floor / tatami mat.

However, in consideration of cleaning the wooden floor / tatami with the main nozzle 7 as it is, it is necessary to rotate the impeller 4 as low as possible.

When the auxiliary blade 4d is provided in the impeller 4 having four blades 4a, the torque increases on the low rotation side, and the characteristic of only four blades can be maintained on the high rotation side. Due to this characteristic, even under a light load, the rotation speed can be lower than the conventional one.

The blade 4a of the impeller 4 is moved by the jet air stream 8
The sound of blade-cutting that occurs across the circle is determined by the product of "the number of rotations" and "the number of blades."

When the natural frequency of the turbine impeller 4 including the impeller 4 and the shaft 10 and the frequency of the exciting force determined by the product of the "rotation speed" and the "number of blades" match, a resonance sound is produced. The blade noise is increased.

Therefore, if the number of blades is changed from 8 to 4, the vibration frequency can be halved and the vibration frequency can be separated from the natural frequency of the turbine.

In the above-mentioned impeller having an outer diameter of φ40.8 blades, the natural frequency of the shaft diameter φ6 is about 2,500 Hz, and the rotation speed of the regular impeller due to the load fluctuation of the surface to be cleaned is 7,000.
~ 12,000r / min, so 10,000r
Maximum noise occurs at around / min.

However, by reducing the number of blades, it becomes easy to avoid the resonance frequency. Further, according to the experiment, since only one blade 4a of each impeller 4 exists in the height region of the main nozzle 7, vortex generation due to turbulent flow between the blades is reduced and noise is generated. Suppressed.

Further, the diffusion of the jet airflow 8 colliding with the impeller by the auxiliary blades generates a new rotational force and contributes to the increase of the torque. Conventionally, this turbulent flow collides with the peripheral wall in the casing. The collision noise and the vortex noise caused by the turbulent flow were reduced and the noise was reduced.

The noise generated when cleaning the carpet floor was 62 dB when the suction air volume of the cleaner body was 1.4 m ³ / min, and the maximum air volume was 1.8 m ^3.
Although it was 69 dB at / min, with the configuration of the present invention, a significant reduction of 4 to 5 dB was achieved at 58 dB and 64 dB, respectively.

With the above structure, the rotational force generated when the high-speed jet stream jetted from the main nozzle collides with the air turbine impeller can be increased on the low speed side and reduced on the high speed side, so that a heavy load is applied. It is powerful for cleaning carpet floors, and can be used to softly clean tatami or wooden floors with a light load at a lower rotation speed than before, and can be adapted to the floor quality.

Further, since the flow of airflow can be effectively utilized,
Generation of vortices due to turbulence is reduced, and noise can be reduced by 4 to 5 dB.

Further, since it is easy to avoid resonance with the natural frequency of the component parts, this resonance sound can be greatly reduced, and a pleasant sound can be obtained.

[0096]

According to the present invention, the jet airflow can be efficiently converted into a rotational force by the impeller, the rotational force can be increased on the low speed side and reduced on the high speed side. It has the effect of significantly reducing blade noise (wind noise) and resonance noise.

[Brief description of drawings]

FIG. 1 is a perspective view of a suction tool equipped with an air turbine according to the present invention.

FIG. 2 is a cross-sectional view taken along a plane parallel to the floor surface to be cleaned of FIG.

FIG. 3 is a cross-sectional view taken along line XX ′ perpendicular to the rotation axis of the impeller of FIG.

FIG. 4 is a perspective view of an impeller alone.

FIG. 5 is an explanatory diagram showing a positional relationship between blades of an impeller and nozzles.

FIG. 6 is an explanatory diagram showing the results of a comparative experiment between the configuration according to the present invention and a conventional example.

[Explanation of symbols]

1 ... Upper case, 2 ... Lower case, 3 ... Rotary brush,
4 ... Air turbine impeller, 4a ... Blade, 4b ... Blade L, 4c ... Blade R, 4d ... Auxiliary blade, 4e ... Side wall, 5 ...
Shutter opening / closing mechanism, 5a ... Shutter, 5b ... Pick, 6 ...
Nozzle support plate, 7 ... Main nozzle, 8 ... High-speed jet stream,
8a ... Diffusion jet air flow, 9 ... Discharge air flow, 10 ... Shaft, 11 ... Pulley, 12 ... Timing belt, 13 ... Ball bearing bearing, 14 ... Bearing holder, 15 ... Rotating joint, 16 ... Turbine chamber, 17 ... L side wall , 18 ... R side wall,
19 ... Rear wall, 20 ... Bypass nozzle, 21 ... Push-on fix, 22 ... Rotary brush chamber, 23 ... Suction air, 24 ... Gap.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shigenori Sato 502 Jinritsucho, Tsuchiura-shi, Ibaraki Prefecture Hiritsu Manufacturing Co., Ltd. Mechanical Research Laboratory

Claims (1)

[Claims] 1. A divided air turbine impeller, which is rotated around a shaft by a suction airflow impinging on a plurality of blades extending outward from the shaft, and a drive source for the air turbine impeller. In an air turbine suction tool of an electric vacuum cleaner equipped with a rotary brush rotating as a blade, the blades of the air turbine impeller are displaced from each other, the central axis of the nozzle and the split surface of the air turbine impeller are aligned, and the height of the nozzle is There is only one blade of the impeller divided into each area, and the blade outer circumference on both side walls of the impeller extends axially from outside the width area of the nozzle.
An air turbine suction tool for an electric vacuum cleaner, further comprising an auxiliary blade extending in the direction of the rear blade.