JPH06123300A - Electric fan for cleaner - Google Patents

Abstract

PURPOSE:To obtain an electric fan for a cleaner which restrains separation of an air flow in an air guide and improves efficiency. CONSTITUTION:This electric fan for a cleaner has an impeller 3 constituted by a plurality of blades 5, front shroud 6 and rear 7, a motor 4 in which the impeller is fixed to a rotation shaft, an air guide 21 provided on the outer circumference of the impeller 3 and casing 1 having a suction port for an air flow at the center, and the air guide has a diffuser part 23 consisting of a plurality of stator vanes 22 and a return passage part 24. A linear projection 25 is provided at the side of the stator vane 22 on the diffuser 23 side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improving the efficiency of an electric blower used in a household vacuum cleaner.

[0002]

2. Description of the Related Art In recent years, electric vacuum cleaners using an electric blower have been tending toward higher output in order to cope with applications such as cleaning carpets and sucking mites. Below, the conventional electric blower for vacuum cleaners is demonstrated based on FIG. Reference numeral 1 denotes a casing in which an air guide 2 and an impeller 3 are housed, which is attached to a motor 4 in an airtight manner. Impeller 3
It is composed of a blade 5, an umbrella-shaped front shroud 6 sandwiching the blade 5, and a disc-shaped rear shroud 7, and is fixed to a rotating shaft 8 of a motor 4.

With the above construction, the impeller 3 is rotated at a high speed by the motor 4, and the generated centrifugal force provides the air volume and vacuum pressure required for the cleaner. The airflow caused by the rotation of the impeller 3 gradually reduces the flow velocity in the diffuser portion 9 of the air guide 2 to recover the pressure, and then passes through the return passage 10 to cool the motor 4.
And is discharged from an exhaust hole 12 provided in the motor bracket 11.

[0004]

The electric blower for a vacuum cleaner having such a conventional structure has the following problems. That is, first, the airflow discharged from the impeller 3 is suddenly recovered by the diffuser portion 9 of the air guide 2. For this reason, separation of the boundary layer occurs in the diffuser portion 9, which is one of the causes of lowering the efficiency.

Secondly, among the airflows discharged from the impeller 3, the airflows that do not enter the diffuser portion 9 but slightly flow between the vanes 13 of the air guide 2 and the outer periphery of the impeller 3 are the vanes. In the vicinity of 13, due to the separation of the boundary layer, it flows toward the impeller 3 side, and this imposes a load on the rotation of the impeller 3,
This is a cause of lowering the efficiency of the impeller 3.

Further, since the airflow discharged from the impeller 3 is high speed, the collision with the end of the air guide 2 causes pressure fluctuation of the flow, which causes noise.

The present invention solves the above-mentioned problems of the conventional structure, and a first object thereof is to provide a highly efficient electric blower for a vacuum cleaner by suppressing separation in the boundary layer of the flow. There is.

Secondly, it is necessary to prevent the airflow slightly flowing between the stationary blades of the air guide and the outer circumference of the impeller from exerting a load on the rotation of the impeller so as not to impair the efficiency of the impeller. Has an aim.

A third object is to provide an electric blower for a vacuum cleaner with reduced noise.

[0010]

A first means of the present invention for achieving the first object is to provide an impeller composed of a plurality of blades, an umbrella-shaped front shroud and a disc-shaped rear shroud. , A motor having the impeller fixed to a rotating shaft, an air guide having a diffuser portion provided on the outer periphery of the impeller, the diffuser portion including a plurality of stationary blades, and a return passage portion for guiding an air flow into the motor, the air guide and the impeller. An electric blower for a vacuum cleaner, which is provided with a casing attached to the outer periphery of a motor having an air inlet for air flow in the center, and having linear projections on the side surfaces of the vanes on the diffuser side of the air guide. is there.

A second means of the present invention for achieving the second object is an electric blower for a vacuum cleaner having a linear projection on the side surface of the vane on the impeller side of the air guide.

A third means of the present invention for achieving the third object is an electric blower for a vacuum cleaner, which has a linear projection having a circular cross section at the tip of a vane of an air guide. To do.

[0013]

The first means of the present invention is that the projections provided on the side surfaces of the vanes on the diffuser portion side of the air guide act to suppress the separation of the air flow. That is, the vortex flow that flows through the protruding portion holds the boundary layer on the boundary surface and suppresses the separation of the air flow.

According to the second means of the present invention, the projections provided on the side surface of the vane on the impeller side of the air guide cause a swirl in the air flow flowing between the vane of the air guide and the impeller, thereby separating the air flow. Is to suppress. Therefore, the airflow flowing between the vanes of the air guide and the impeller does not flow into the impeller side. Therefore, the efficiency of the impeller is not reduced by imposing a load on the rotation of the impeller.

A third means of the present invention is that a linear projection having a circular cross section is provided at the tip of the vane of the air guide.
The pressure fluctuation of the flow due to the collision of the high-speed airflow discharged from the impeller is reduced, and the noise is reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the first means of the present invention will be described below with reference to FIGS. The same parts as those in the conventional example are designated by the same reference numerals and the description thereof will be omitted. The air guide 21 provided around the impeller 3 has a diffuser portion 23 formed by a plurality of vanes 22 and a return passage 24 that guides the airflow into the motor 4. A diffuser portion 23, which is an airflow passage surrounded by two vanes 22
Has a passage area increasing toward the outer peripheral side.
Reference numeral 25 denotes a linear protrusion provided in the vertical direction on the side surface of the stationary blade 22 on the diffuser portion 23 side of the air guide 21. Reference numeral 26 is an intake port provided at the upper center of the casing 1.

The operation of this embodiment will be described below. When the motor 4 is driven, the impeller 3 rotates at high speed, and air is sucked in through the intake port 26 of the casing 1. This air flow (hereinafter referred to as “air flow”) is discharged in the outer peripheral direction of the impeller 3 and guided into the motor 4 by the air guide 21. At this time, the centrifugal force generated by the high-speed rotation of the impeller 3 acts so as to obtain the air volume and the vacuum pressure required for the cleaner. Further, the air flow gradually reduces its flow velocity in the diffuser portion 23 of the air guide 21 to recover the pressure, then cools the motor 4 via the return passage 24 and is discharged from the exhaust hole 12 provided in the motor bracket 11. It

In order to improve the efficiency of the electric blower, it is necessary to reduce the loss of the air flow. One of the airflow losses is boundary layer separation. That is, like the flow of the diffuser portion 23 of the air guide 21, when the airflow flows along the boundary layer such as the stationary blades 22 and the pressure gradually increases, the separation of the airflow in the boundary layer occurs. It is a problem. That is, when separation occurs, backflow occurs and loss occurs. In particular, in the case where the airflow discharged from the impeller 3 is at high speed to obtain a high pressure and the pressure is suddenly recovered by the diffuser portion 23 of the air guide 21, the inside of the diffuser portion 23 This peeling is likely to occur in the boundary layer. In this embodiment, since the protrusion 25 is provided on the side surface of the vane on the diffuser portion 23 side of the air guide 21 in order to prevent the separation in the boundary layer, a small vortex is generated in the airflow flowing through this portion. This eddy current acts to hold the boundary layer of the air flow on the boundary surface. Therefore, according to the present embodiment, it is possible to suppress the separation of the air flow in the boundary layer, realize a highly efficient electric blower with reduced loss.

Next, an embodiment of the second means of the present invention will be described with reference to FIG. The electric blower for a vacuum cleaner of the present embodiment is provided with a linear protrusion 29 in the vertical direction on the side surface of the vane 28 on the impeller side of the air guide 27. 30 is a diffuser part. Other configurations are the same as those of the first embodiment of the present invention.

The operation will be described below. In the electric blower having the conventional configuration, a part of the airflow discharged from the impeller 3 does not enter the diffuser portion 30 but flows between the vanes 28 of the air guide 27 and the outer periphery of the impeller 3.
This flow acts on the airflow entering the diffuser portion 30 so as to cause separation of the boundary layer near the vane 28. In this embodiment, a linear protrusion 29 is provided on the side surface of the stationary blade 28 on the impeller side of the air guide 27.
As in the case of the above-described embodiment, a small eddy current is generated in the airflow flowing through this portion of the protrusion 29. This eddy current acts to hold the boundary layer of the air flow on the boundary surface. Therefore, the airflow entering the diffuser portion 30 is less likely to cause separation of the boundary layer near the vane 28, does not flow into the impeller 3 side, does not impose a load on the rotation of the impeller 3, and impairs the efficiency of the impeller. It is possible to realize a highly efficient electric blower for a vacuum cleaner.

Next, an embodiment of the third means of the present invention will be described with reference to FIG. In this embodiment, a linear protrusion 33 having a circular cross section is provided at the tip of the vane 32 of the air guide 31. Other configurations are similar to those of the first embodiment of the present invention.

With the above construction, the protrusion 33 acts to reduce noise. That is, the behavior of the airflow discharged from the impeller 3 colliding with the stationary blades 32 of the air guide 31 is alleviated by providing the linear projections 33 having a circular cross section at the tips of the stationary blades 32. is there.
That is, in the conventional configuration, the tip portion of the vane 32 has a planar cross section. In this respect, in the present embodiment, since the projection 33 has a circular cross section, this collision is relatively gentle. As described above, according to the present embodiment, it is possible to provide an electric blower for a vacuum cleaner in which the pressure fluctuation of the flow due to the collision of the high-speed airflow discharged from the impeller is reduced and the noise is reduced.

[0023]

The first means of the present invention is to provide an impeller comprising a plurality of blades, an umbrella-shaped front shroud and a disc-shaped rear shroud, a motor having the impeller fixed to a rotating shaft, and an impeller. An air guide having a diffuser portion composed of a plurality of stationary blades and a return passage portion for guiding the air flow into the motor, and a motor having the air guide and the impeller in the center and having an air inlet for the air flow A highly efficient electric blower for a vacuum cleaner that has a casing attached to the outer periphery and has a linear projection on the side surface of the vane on the diffuser side of the air guide, which suppresses air flow separation and reduces loss. Is what you can do.

The second means of the present invention has a linear projection on the side surface of the vane on the impeller side of the air guide, so that an air flow flowing between the air guide and the impeller can be prevented. Therefore, the electric blower for the cleaner can be made more efficient.

The third means of the present invention has the linear projection having a circular cross section at the tip of the vane of the air guide, so that the air flow discharged from the impeller collides with the air guide. This is an electric blower for a vacuum cleaner that can reduce the impact at the time and has low noise.

[Brief description of drawings]

FIG. 1 is a sectional view of an electric blower for a vacuum cleaner, which is an embodiment of the first means of the present invention.

FIG. 2 is a plan view of the air guide.

[Figure 3] Rear view of the air guide

FIG. 4 is a partial perspective view of the air guide.

FIG. 5 is a partial perspective view of an air guide in the embodiment of the second means of the present invention.

FIG. 6 is a partial perspective view of an air guide in the embodiment of the third means of the present invention.

FIG. 7 is a sectional view of an electric blower showing a conventional example.

[Explanation of symbols]

 1 Casing 3 Impeller 4 Motor 12 Exhaust hole 21/27/31 Air guide 22/28/32 Stator vane 23/30 Diffuser part 25/29/33 Protrusion 26 Intake port

Claims (3)

[Claims] 1. An impeller composed of a plurality of blades, an umbrella-shaped front shroud, and a disc-shaped rear shroud, a motor in which the impeller is fixed to a rotating shaft, and a plurality of impellers installed on the outer periphery of the impeller. An air guide having a diffuser section composed of stationary vanes and a return passage section for guiding an air flow into the motor, and including the air guide and the impeller,
An electric blower for a vacuum cleaner, comprising: a casing attached to an outer periphery of a motor having an air intake port in a central portion, and having a linear projection on a side surface of a vane on a diffuser side of an air guide. 2. An impeller composed of a plurality of blades, an umbrella-shaped front shroud and a disk-shaped rear shroud, a motor having the impeller fixed to a rotating shaft, and a plurality of impellers installed on the outer periphery of the impeller. An air guide having a diffuser section composed of stationary vanes and a return passage section for guiding an air flow into the motor, and including the air guide and the impeller,
An electric blower for a vacuum cleaner, comprising: a casing attached to an outer periphery of a motor having an air inlet for air flow in a central portion thereof; and a linear projection on a side surface of a vane on an impeller side of an air guide. 3. An impeller composed of a plurality of blades, an umbrella-shaped front shroud, and a disc-shaped rear shroud, a motor in which the impeller is fixed to a rotating shaft, and a plurality of impellers installed on the outer periphery of the impeller. An air guide having a diffuser section composed of stationary vanes and a return passage section for guiding an air flow into the motor, and including the air guide and the impeller,
An electric blower for a vacuum cleaner, comprising: a casing attached to an outer periphery of a motor having an air intake port in a central portion, and a linear protrusion having a circular cross section at a tip of a vane of an air guide.