JP5784066B2 - Centrifugal impeller, electric blower and vacuum cleaner - Google Patents

Description

  The present invention relates to a centrifugal impeller, an electric blower, and a vacuum cleaner.

  Conventionally, as an electric blower used for what is called a vacuum cleaner, there exists a thing indicated by patent documents 1, for example. The electric blower includes an annular shroud, a hub disposed opposite to the shroud, a plurality of blades disposed in a circumferential direction between the shroud and the hub, and an electric unit that rotates the shroud, the hub, and the blades. It has. And in such an electric blower, for high efficiency, each blade is formed with a flat plate, and the formation direction of each blade with respect to the hub is inclined in the rotation direction at the intermediate portion compared to the inner edge and outer edge of the blade. Yes.

JP 2010-270750 A (page 16, FIG. 4)

  In general, in a centrifugal blower that guides the flow from the axial direction in the above configuration to the centrifugal direction, the flow at the inlet is biased toward the hub side, and the air volume of the air that passes between the shroud side and the hub side is different. is there. If the leading edge (inner edge) of the blade is almost two-dimensional, adopting a blade installation angle that matches the air volume on the hub side, the incident angle (from the inflow angle) on the shroud side where the flow rate is lower than the hub side. There is a problem that loss occurs such that the blade installation angle is minus) and peeling occurs. In addition, even when the blade installation angle that matches the air volume on the shroud side is adopted, the incident angle becomes excessive on the hub side where the air volume is larger than the shroud side, separation occurs, loss occurs, input increases, There was a problem that efficiency became low.

  The present invention has been made in view of the above problems, and is a highly efficient centrifugal impeller, electric blower, and electric that can make the airflow distribution at the moving blade inlet uniform and reduce the loss at the inlet. The purpose is to provide a vacuum cleaner.

  In order to achieve the above object, the present invention provides a centrifugal impeller comprising a hub, a shroud provided so as to face the hub, and a plurality of moving blades provided between the hub and the shroud. The axial height of the trailing edge of each of the moving blades is half the axial height of the leading edge, from the leading edge of each of the moving blades to the middle position of the chord length of the moving blade. And the shroud side region with respect to the intermediate height is inclined in the rotational direction, and the leading edge of each of the moving blades moves away from the trailing edge as it approaches the shroud side with respect to the intermediate height. The angle of installation of the leading edge of the region inclined in the rotational direction of each of the blades is greater than the angle of installation of the leading edge on the hub side than the intermediate height. It is also a small centrifugal impeller.

  ADVANTAGE OF THE INVENTION According to this invention, the highly efficient centrifugal impeller etc. which can equalize the airflow distribution of a moving blade inlet and can reduce the loss of an inlet part can be provided.

It is the schematic of the vacuum cleaner which concerns on Embodiment 1 of this invention. It is sectional drawing which shows the inside of the electric blower which concerns on this Embodiment 1. FIG. It is a perspective view of a centrifugal impeller. It is a figure explaining the form of the moving blade in a centrifugal impeller. It is a figure explaining the entrance installation angle of a centrifugal impeller. It is a figure which shows the form of the moving blade of the centrifugal impeller as a comparative example. It is a graph which shows the passage air volume ratio of the inlet part of a moving blade regarding this Embodiment 1 and a comparative example. It is a graph which shows the incident angle regarding this Embodiment 1 and a comparative example. It is a graph which shows the inlet relative speed of the moving blade regarding this Embodiment 1 and a comparative example. It is a graph which shows the input and efficiency at the time of performing the fluid analysis of an electric blower regarding this Embodiment 1 and a comparative example.

  Hereinafter, embodiments of a centrifugal impeller, an electric blower, and a vacuum cleaner according to the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram of a vacuum cleaner according to Embodiment 1 of the present invention. The vacuum cleaner according to Embodiment 1 includes a vacuum cleaner main body 1, a hose 2 connected to the vacuum cleaner main body 1, an extension pipe 3 connected to the hose 2, and a suction attached to the tip of the extension pipe 3. The tool 4 is provided.

  Inside the vacuum cleaner main body 1, the dust of the air sucked by the suction tool 4 is collected and stored, and the suction force for sucking air from the suction tool 4 to the dust collection part 5 And an electric blower 6 for generating

  Behind the vacuum cleaner main body 1, there is provided a discharge port 7 for discharging the air after being collected by the dust collector 5 to the outside of the vacuum cleaner main body 1.

  Further, the vacuum cleaner body 1 is provided with a front wheel (not shown) and a rear wheel 8 for assisting the traveling movement of the vacuum cleaner body 1. The front wheel is provided at a front portion in the traveling direction on the lower surface of the vacuum cleaner body 1, and the rear wheel 8 is provided at a rear portion in the traveling direction on both side surfaces of the vacuum cleaner body 1. In addition, the front-back direction in the vacuum cleaner main body 1 has demonstrated the direction which the vacuum cleaner main body 1 advances according to the pulling of the hose 2 by a user as "front".

  FIG. 2 is a cross-sectional view showing the inside of the electric blower according to the first embodiment. The arrows in FIG. 2 indicate the air flow.

  An electric motor 9 and a centrifugal impeller 11 fixed to the shaft 10 of the electric motor 9 are provided inside the electric blower 6.

  A plurality of stationary blades 12 are provided on the centrifugal impeller 11 side between the electric motor 9 and the centrifugal impeller 11, and on the opposite side of the centrifugal impeller 11 between the electric motor 9 and the centrifugal impeller 11. A plurality of return vanes 13 are provided. Further, on the downstream side (rear side) of the centrifugal impeller 11, a diffuser 15 having a main plate 14 that connects the stationary blade 12 and the return stationary blade 13 is provided.

  A fan guide 16 that includes the centrifugal impeller 11 and the stationary blade 12 is provided on the upstream side (front side) of the centrifugal impeller 11. The inner diameter of the fan guide 16 is larger than the outer diameter of the stationary blade 12, the stationary blade 12 is arranged on the radially outer side of the centrifugal impeller 11, and the fan guide 16 further includes the centrifugal impeller 11 and the stationary blade. 12 is covered from the outside in the radial direction.

  A bell mouth 18 is provided in a central portion (near the rotation axis) of the fan guide 16 and at a position facing the suction port 17 of the centrifugal impeller 11. The bell mouth 18 is an annular edge portion that is folded back toward the centrifugal impeller 11 in the fan guide 16. In other words, the suction port 17 is defined by the annular edge portion.

  A bracket 19 and a motor frame 20 are further provided on the side surface of the electric blower 6. The front portion of the bracket 19 is connected to the rear portion of the fan guide 16, and the bracket 19 includes the return stationary blade 13. The front part of the motor frame 20 is connected to the rear part of the bracket 19, and the main part of the electric motor 9 is included in the motor frame 20.

  A gap 21 serving as a flow path from the stationary blade 12 toward the stationary vane 13 is provided between the inside of each outer peripheral side surface of the fan guide 16 and the bracket 19 and the diffuser 15.

  The motor frame 20 is provided with several discharge holes 22 through which the air that has passed through the centrifugal impeller 11, the diffuser 15, and the electric motor 9 is discharged.

  Furthermore, the detail of a centrifugal impeller is demonstrated using FIGS. FIG. 3 is a perspective view of the centrifugal impeller. An arrow RD indicates the rotation direction of the centrifugal impeller. FIG. 4 is a diagram for explaining the configuration of the moving blades in the centrifugal impeller. In particular, the upper part in FIG. 4 is a perspective view of one moving blade, and the lower part is a section of the moving blade in a plan view with respect to a portion closer to the leading edge of the moving blade. FIG. FIG. 5 is a view for explaining the inlet installation angle of the centrifugal impeller. In the description, the height direction refers to the direction of the rotation axis of the centrifugal impeller.

  The centrifugal impeller 11 includes a hub 23, a shroud 24, and a plurality of moving blades 25. The hub 23 is located on the downstream side of the centrifugal impeller 11 and is a disk-shaped portion that faces the diffuser 15. The shroud 24 is located on the upstream side of the centrifugal impeller 11 and is an annular portion provided so as to face the hub 23. The plurality of moving blades 25 are provided between the hub 23 and the shroud 24 and are blade portions arranged in the circumferential direction.

  The moving blade 25 has a leading edge 26 as an upstream end relating to the flow along the blade, and a trailing edge 27 serving as a downstream end relating to the flow along the blade. The axial height (dimension in the rotational axis direction) of the trailing edge 27 that is the downstream end is approximately half the axial height of the leading edge 26 that is the upstream end. Further, the moving blade 25 has a cross section of each height (a virtual cross section perpendicular to the rotation axis) having a substantially arc shape. Furthermore, the direction of the arc is such that the front side in the rotational direction swells.

  In order to describe the configuration of the moving blade 25, the first height virtual section 28-1, the second height virtual section 28-2, and the intermediate height virtual section 29 having three axial heights with respect to the moving blade 25 are illustrated. Think about it. The intermediate height virtual section 29 is a plane orthogonal to the axial direction and passing through a position that is half the axial height of the leading edge 26. The second virtual height section 28-2 is a plane perpendicular to the axial direction and passes through the vicinity of the end portion on the shroud 24 side of the front edge 26. The first height virtual section 28-1 is a plane orthogonal to the axial direction, and passes through the middle of the height direction between the second height virtual section 28-2 and the intermediate height virtual section 29. is there.

  In the virtual plane as described above, the moving blade 25 is a region from the leading edge 26 to a substantially intermediate position 25a of the blade chord length of the moving blade, and is closer to the shroud 24 than the intermediate height virtual section 29 ( The region on the upper side of the drawing in FIG. 4 is inclined in the rotation direction (outside of the curve, outside in the radial direction). This is because the second height virtual section 28-2 and the first height virtual section 28-1 are located on the front side in the rotational direction with respect to the intermediate height virtual section 29 in the projection portion of FIG. 4. You can see from

  Further, the position of the front edge 26 itself also changes over the height direction. The leading edge 26 is tilted away from the trailing edge 27 as it approaches the shroud 24 side of the intermediate height imaginary cross section 29, and the trailing edge as it approaches the hub 23 side of the intermediate height imaginary section 29. It is tilted away from 27. That is, as shown in the projection view part of FIG. 4, the front edge portion 26-1 in the first height virtual section 28-1 is more than the front edge section 26-0 in the intermediate height virtual section 29. Is at a position outside the curve and away from the trailing edge 27, and the leading edge in the second height virtual section 28-2 than the leading edge 26-1 in the first height virtual section 28-1. The part 26-2 is located outside the curve and away from the trailing edge 27. Further, on the opposite side, the front edge portion 26-3 closer to the hub 23 is further away from the rear edge 27 than the front edge portion 26-0 in the intermediate height virtual section 29, and the front edge The front edge portion 26-4 closer to the hub 23 is located farther from the rear edge 27 than the portion 26-3.

  Further, a portion of the moving blade 25 excluding the above-described region that is inclined in the rotation direction (outside of the curve) (a region that is mostly on the hub 23 side of the intermediate height virtual section 29) has a two-dimensional shape. That is, a uniform curvature is maintained over the height direction (in a plan view, they are included in the same arc).

  Further, when the position of the front edge 26 across the height direction is viewed in relation to the radial direction around the rotation axis, the position of the front edge 26 is gradually increased from the hub 23 side to the shroud 24 side in the radial direction. It has changed to.

  As shown in FIG. 5, the moving blade row includes a moving blade inlet relative flow angle CA at the center between the blades as an angle with respect to the locus circle 30 on the locus circle 30 when the leading edge of the moving blade rotates. There is an entrance installation angle SA. The inlet diameter D1 on the shroud 24 side of the plurality of rotor blades 25 is larger than the inlet diameter D2 of the shroud 24 itself (see FIG. 2). In the first embodiment, the inlet installation angle of the leading edge (the leading edge on the shroud 24 side of the intermediate height virtual section 29) of the above-described region inclined in the rotation direction of the moving blade 25 is the virtual height of the intermediate blade. The cross section 29 is configured to be smaller than the entrance installation angle at the front edge on the hub 23 side. That is, on the shroud 24 side of the intermediate height virtual section 29, the inlet installation angle of the leading edge is continuous over the height direction from the inlet installation angle of the front edge on the hub 23 side of the intermediate height virtual section 29. Is also small. The entrance installation angle at the front edge on the hub 23 side of the intermediate height virtual section 29 is a constant value due to the two-dimensional shape.

  Next, operation | movement of the vacuum cleaner which concerns on this Embodiment 1 comprised as mentioned above is demonstrated. When electric power is supplied to the electric motor 9, the centrifugal impeller 11 attached to the shaft 10 rotates by the shaft 10 rotating and sucks air from the suction port 17. Thereby, the air on the surface to be cleaned is sucked into the vacuum cleaner body 1 through the hose 2, the extension pipe 3, and the suction tool 4 connected to the vacuum cleaner body 1. The air sucked into the vacuum cleaner main body 1 is collected in the dust collecting unit 5, and then sucked from the suction port 17 of the centrifugal impeller 11 through the bell mouth 18 of the electric blower 6. The air sucked into the centrifugal impeller 11 is increased in pressure and accelerated by the centrifugal impeller 11, and travels radially outward while turning. The air discharged from the centrifugal impeller 11 is decelerated and boosted between the vanes of the stationary blade 12 of the diffuser 15. Thereafter, the air passes through the gap 21 between the diffuser 15 and the fan guide 16 and is guided to the electric motor 9 side by the return vane 13 to cool the electric motor 9. Then, it discharges | emits from the discharge hole 22 provided in the motor flame | frame 20 to the outer side of the electric blower, and is further discharged | emitted from the discharge port 7 provided in the vacuum cleaner main body 1 to the outer side of the vacuum cleaner main body 1. FIG.

  Next, the performance of the centrifugal impeller according to the first embodiment will be described using FIGS. 6 to 10 and comparing with a comparative example. FIG. 6 is a view showing a configuration of a moving blade of a centrifugal impeller as a comparative example. The centrifugal impeller 111 of the comparative example has a substantially two-dimensional shape at the front edge and the rear edge. In the above-mentioned prior art document, the intermediate part of the rotor blade was introduced in the direction of rotation compared to the leading edge and the trailing edge. However, for the sake of simplicity of explanation, the intermediate part also has a substantially two-dimensional shape. A comparative example is used.

  FIG. 7 is a graph showing the passing air volume ratio at the inlet portion of the moving blade in the first embodiment and the comparative example. The passage air volume ratio at the inlet is obtained by conducting a fluid analysis of the electric blower. In the fluid analysis, the passage air volume is related to a cross section obtained by dividing the inlet portion of the moving blade into four equal parts in the rotation axis direction from the shroud to the hub. The percentage was determined. As can be seen from FIG. 7, in the comparative example, the air flow was biased toward the hub side, but in the first embodiment, the bias toward the hub side was reduced, and the air flow increased on the shroud side accordingly. It can be seen that the airflow distribution between the hub and the shroud is approaching to be uniform.

  Moreover, FIG. 8 is a graph which shows the incident angle regarding this Embodiment 1 and a comparative example. The incident angle is an angle obtained by subtracting the inlet installation angle SA from the rotor blade relative flow angle CA described above, and is obtained by performing fluid analysis of the electric blower. In the fluid analysis, rotation from the shroud to the hub is performed. It calculated | required about 3 points | pieces of an axial direction. As shown in FIG. 8, in the comparative example, since the air volume ratio on the shroud side is low, the incident angle on the shroud side becomes extremely negative, and peeling occurs at the leading edge. On the other hand, in the first embodiment, since the incident angle is close to 0 degrees from the shroud to the hub, large separation does not occur, and air flows along the moving blade, so that the loss is low.

  Furthermore, FIG. 9 is a graph showing the inlet relative velocity of the moving blades in the first embodiment and the comparative example. The inlet relative speed of the moving blade was obtained by performing fluid analysis of the electric blower, and was obtained for three points in the rotational axis direction from the shroud to the hub as in FIG. As shown in FIG. 9, in the comparative example, since the air volume ratio on the shroud side is low, it can be seen that the inlet relative speed difference is large between the shroud side and the hub side. This has the disadvantage of high mixing loss. In contrast, the first embodiment has the advantage that the inlet relative speed is substantially uniform from the shroud to the hub, and the mixing loss is low.

  Further, FIG. 10 is a graph showing the input and efficiency when the fluid analysis of the electric blower is performed with respect to the first embodiment and the comparative example. As shown in FIG. 10, in the comparative example, as is clear from the results of FIGS. 7 to 9, the loss at the inlet of the moving blade is high, so the input is high and the efficiency is low. On the other hand, in the first embodiment, it can be seen that the input is low because the loss at the inlet of the moving blade is low, and the efficiency is high.

  As described above, according to the present invention, the region from the leading edge of each blade to the middle position of the chord length of the blade, and the region on the shroud side with respect to the intermediate height is inclined in the rotational direction. The leading edge of each blade is tilted away from the trailing edge as it approaches the shroud side rather than the intermediate height, and the front edge of the above-mentioned region that is tilted in the direction of rotation of each blade. Since the edge installation angle of the edge is smaller than the intermediate edge height, the inlet installation angle of the leading edge is smaller than the intermediate height, and the axial height air volume ratio between the shroud and the hub at the inlet portion of the moving blade is made uniform. Since the incident angle is optimized (the flow is close to 0 degrees and the flow follows the moving blade) and the relative velocity distribution at the inlet is made uniform, the collision loss between the air and the leading edge is reduced at the leading edge. The mixing loss of air at the blade inlet is also reduced. Because the input is low, it is possible to obtain a high efficiency blower.

  Further, in each of the moving blades, if the portion excluding the region inclined in the rotation direction has a two-dimensional shape, when the hub and the shroud are connected to the moving blade, a caulking process is performed to apply a force in the axial direction. Even if connected together, the moving blades do not fall down, the defective rate during assembly is reduced, and the manufacturing cost can be reduced.

  If the position of the leading edge of the rotor blade is configured to gradually change radially outward from the hub side to the shroud side, the suction flow from the suction mouth of the bell mouth is from the axial direction. On the shroud side with a large turning angle when turning in the radial direction, the suction flow turns in the radial direction from the axial direction and does not immediately flow into the blade, but is rectified in the radial direction by the shroud and then flows into the blade. Therefore, the disturbance is reduced. Even with this, the loss is reduced, the input is low, and a highly efficient blower can be obtained.

  In addition, if each of the moving blades is configured such that the cross-sectional shape of each height is formed in an arc shape, the flow flowing into the leading edge can be smoothly guided to the trailing edge side, loss is reduced, A fan with low input and high efficiency can be obtained.

  Also, if the inlet diameter on the shroud side of the plurality of moving blades is configured to be larger than the inlet diameter of the shroud, the centrifugal impeller is axially moved during rotation (when the electric vacuum cleaner is operating). Even if it moves, the moving blade and the shroud do not rub or collide with each other, so that the reliability during rotation (when the electric vacuum cleaner is operated) is improved.

  Although the contents of the present invention have been specifically described with reference to the preferred embodiments, various modifications can be made by those skilled in the art based on the basic technical idea and teachings of the present invention. It is self-explanatory.

  Examples of utilization of the present invention include use in household and commercial vacuum cleaners that require a high suction work rate and reduced manufacturing costs, but the present invention is not limited to this. . The present invention can be used as a blower and can also be used as a suction device. As an example, the blower can be applied to a dryer or a drying facility, and the suction device can be applied to a dust collector or a ventilator in addition to the above vacuum cleaner.

  DESCRIPTION OF SYMBOLS 1 Vacuum cleaner main body, 4 Suction tool, 5 Dust collection part, 6 Electric blower, 7 Discharge port, 9 Electric motor, 11 Centrifugal impeller, 17 Suction port, 18 Bell mouth, 23 Hub, 24 Shroud, 25 Rotor blade, 26 Front edge, 26-1, 26-2, 26-3, 26-4, 26-5 front edge, 27 rear edge, 28-1 first height virtual section, 28-2 second height virtual section, 29 Virtual height virtual section.

Claims (7)

A hub,
A shroud provided to face the hub;
A centrifugal impeller comprising a plurality of blades provided between the hub and the shroud,
The axial height of the trailing edge of each of the blades is half of the axial height of the leading edge;
The region from the leading edge of each of the blades to the middle position of the chord length of the blade, the region on the shroud side with respect to the intermediate height is inclined in the rotation direction,
The leading edge of each of the blades is tilted away from the trailing edge as it approaches the shroud side rather than the intermediate height,
The inlet installation angle of the leading edge of the shroud side region inclined in the rotational direction of each of the moving blades is set at the inlet of the leading edge on the hub side relative to the intermediate height of each of the moving blades. Smaller than the corner,
Centrifugal impeller. In each of the rotor blades, the portion excluding the region inclined in the rotation direction has a two-dimensional shape.
The centrifugal impeller of claim 1. The position of the front edge gradually changes from the hub side to the shroud side in the radial direction.
The centrifugal impeller according to claim 1 or 2. Each of the moving blades is formed in an arc shape in cross section at each height,
The centrifugal impeller according to any one of claims 1 to 3. The inlet diameter on the shroud side of the plurality of blades is larger than the inlet diameter of the shroud.
The centrifugal impeller according to any one of claims 1 to 4. A bell mouth having a suction port;
A centrifugal impeller provided downstream of the bell mouth;
An electric motor for rotationally driving the centrifugal impeller,
The centrifugal impeller is the centrifugal impeller according to any one of claims 1 to 5.
Electric blower. The vacuum cleaner body,
Connected to the main body of the vacuum cleaner, a suction tool for sucking air in the portion to be cleaned,
A dust collection unit provided inside the vacuum cleaner main body, communicating with the suction port, and storing dust of sucked air;
An electric blower which is provided inside the vacuum cleaner main body and sucks air from the suction port to the dust collecting part;
Provided on the outside of the vacuum cleaner body, comprising a discharge port for discharging the air after being collected by the dust collecting portion to the outside of the vacuum cleaner body,
The electric blower is the electric blower of claim 6 .
Electric vacuum cleaner.

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