JP2013092160A - Centrifugal blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a centrifugal blower suppressing a decrease in air distribution efficiency and an increase in noise even if a static pressure added to the centrifugal blower is changed.SOLUTION: This centrifugal blower 1 includes an electric motor 6, a centrifugal impeller 7, and a casing 8. The casing 8 is provided with: an outer peripheral wall 12 in substantially parallel with a rotation shaft 5 of the centrifugal impeller 7; a suction side wall 10 having a suction port 9; and an anti-suction side wall 11 facing the suction wall 10. The casing 8 is provided with a movable portion 19, and the inner volume of the casing 8 can be changed. The whole part or a portion of the suction side wall 10 is movable in a direction of the rotation shaft 5 of the centrifugal impeller 7. A suction barrel 23 is provided at the suction port 9 of the suction side wall 10. The outer diameter of the suction barrel 23 is less than the inner diameter of the centrifugal impeller 7.

Description

  The present invention relates to a centrifugal impeller and a centrifugal blower used for, for example, a ventilation blower or an air conditioner.

  In recent years, in ventilation ventilation equipment and air conditioning equipment used in residential and non-residential spaces, downsizing of equipment has been demanded as the installation space has decreased, while centrifugal blowers with improved ventilation efficiency and reduced noise are required. Has been.

  Hereinafter, this type of centrifugal blower will be described with reference to FIG. As shown in FIG. 8, the centrifugal blower 101 sandwiches a side wall 106 having a discharge port 105 in a spiral shape between a suction plate 103 having a bell mouth-like suction port 102 and a back plate 104 facing the suction plate 103. A configured casing 107 and a centrifugal impeller 109 that is attached so as to sandwich a plurality of blades 108 inside the casing 107 to form a multi-blade impeller shape are connected to an electric motor 110 attached to the back plate 104, and the casing Of the back plate 104 of 107, the part outside the centrifugal impeller 109 bulges in the direction of the rotation axis, and the degree of the bulge increases toward the discharge port 105 in the rotation direction (for example, patent) Reference 1).

  With the above configuration, when the centrifugal impeller 109 is rotated by applying a driving force from the electric motor 110, the suction air 111 passes through the suction port 102, flows into the blade 108, is pressurized, and flows out from the blade 108. When passing through the spiral casing 107, the dynamic pressure is gradually converted into static pressure and discharged from the discharge port 105 to the outside. At this time, the portion outside the centrifugal impeller 109 of the back plate 104 of the casing 107 bulges in the direction of the rotation axis, so that the flow path through which the flow out of the centrifugal impeller 109 can pass becomes wider and the wind speed is increased. The generation of turbulent flow can be reduced and the flow path gradually expands toward the discharge port 105, so that the wind speed can be gradually reduced to further suppress the generation of turbulent flow, When the air volume is large, the efficiency of the centrifugal blower 101 can be improved and the noise can be reduced.

Japanese Patent No. 2690005

  In such a conventional centrifugal blower 101, there is an outside such as an obstacle such as a filter placed in front of the centrifugal blower 101, pressure loss in a constricted air passage, pressure loss in a constricted air passage after the discharge port 105, external air pressure, and the like. When the static pressure applied to the blower 101 changes due to a mechanical factor, the rotation of the centrifugal impeller 111 is related to the operation characteristics of the centrifugal blower 101 and the electric motor 110, or to the control method and control content of the electric motor 110. The number changes, and the position of the blade 108 in the axial direction changes mainly in the region where the boosting work is performed. Specifically, when the static pressure applied to the centrifugal blower 101 is small and the air volume is large, the blade 108 performs a lot of work on the back plate 104 side in the axial direction, and thus the flow that flows out from the blade 110 to the casing 107. The main flow 112 is directed toward the back plate 104, and air flows through the entire flow path of the casing 107. Further, when the static pressure applied to the blower 101 is large and the air volume is small, the blade 108 performs a lot of work on the suction port 102 side in the axial direction in order to increase the centrifugal force applied to the air for pressure increase. The main flow 112 of the flow that flows out of the casing 107 approaches a horizontal direction with respect to the rotation axis, and a part of the flow that flows out of the blade 108 again enters the centrifugal impeller 109 from the gap between the suction port 102 and the centrifugal impeller 109. Since it flows in and forms a circulation flow, a part of the main flow 112 is directed toward the suction port 102, and air does not flow through the entire flow path of the casing 107, and the flow is biased toward the suction port 102. Therefore, when the static pressure applied to the centrifugal blower 101 is large and the air volume is small, the flow is biased in the casing 107, turbulent flow is generated in the casing 107, and when the flow path gradually expands, the turbulent flow region further increases. There is a problem that the centrifugal air blowing efficiency decreases and the noise increases, and it is required to suppress the decrease in the air blowing efficiency and the increase in noise even if the static pressure applied to the centrifugal fan 101 changes. .

  This invention solves such a conventional subject, and it aims at providing the centrifugal blower which suppresses the fall of ventilation efficiency and the raise of a noise even if the static pressure added to a centrifugal blower changes. Yes.

  In order to achieve the above object, the centrifugal blower of the present invention includes a power unit, a centrifugal impeller that is rotated by the power unit and blows air, and a casing that includes the centrifugal impeller, and the casing is a rotating shaft of the centrifugal impeller. A centrifugal blower provided with an outer peripheral wall substantially parallel to the suction wall, a suction side wall provided with a suction port, and an anti-suction side wall opposite to the suction side wall, the casing has a movable part, and the inner volume of the casing can be changed. A centrifugal blower characterized by the above.

By this means, in an operating state where the static pressure applied to the centrifugal blower is small and the air volume is large, the internal volume of the casing is increased, and the flow path through which the flow flowing out from the centrifugal impeller is widened to reduce the wind speed. In an operating state where the generation of turbulent flow can be suppressed and the static pressure applied to the centrifugal blower is large and the air volume is small, the inner volume of the casing is reduced, and a biased flow is generated in the casing, resulting in turbulent flow. It is possible to suppress the occurrence of the centrifugal blower, and it is possible to obtain a centrifugal blower capable of suppressing a reduction in blowing efficiency and an increase in noise even when the static pressure applied to the centrifugal blower changes. Another means is a centrifugal blower characterized in that all or a part of the suction and suction side walls are movable in the direction of the rotation axis of the centrifugal impeller. By this means, the position of the suction port can be adjusted with the change in the inner volume of the casing, and a part of the flow that flows out from the centrifugal impeller in the operating state where the static pressure applied to the centrifugal blower is large and the air volume is small is sucked. It is possible to suppress the flow into the centrifugal impeller again from the gap between the mouth and the centrifugal impeller and form a circulation flow. Even if the static pressure applied to the centrifugal blower changes, the blowing efficiency decreases and the noise increases. A centrifugal blower capable of suppressing the above is obtained. Another means is a centrifugal blower characterized in that a suction drum is provided in the suction port of the suction side wall, and the outer diameter of the suction drum is smaller than the inner diameter of the centrifugal impeller. By this means, when the suction side wall moves together with the suction port so that the inner volume of the casing is reduced in an operating state where the static pressure applied to the centrifugal blower is large and the air volume is small, the suction drum may enter the centrifugal impeller. It is possible to prevent a part of the flow flowing out from the centrifugal impeller from flowing into the centrifugal impeller again through the gap between the suction port and the centrifugal impeller to form a circulating flow, and to prevent static electricity added to the centrifugal fan. Even if a pressure changes, the centrifugal blower which can suppress the fall of ventilation efficiency and the raise of a noise is obtained.

  Another means is a centrifugal blower characterized in that it comprises a detection means for detecting the operation state of the centrifugal blower, and automatically adjusts the position of the movable portion according to the detected operation state of the centrifugal blower.

  By this means, even if the static pressure applied to the centrifugal blower changes after the centrifugal blower is installed, the movable part can be automatically operated, and a centrifugal blower that can suppress a decrease in blowing efficiency and an increase in noise is provided. can get.

  Another means is a centrifugal blower characterized in that it includes an air volume detection means for detecting the air volume of the centrifugal blower, and automatically adjusts the position of the movable portion in accordance with the detected air volume.

  By this means, a change in static pressure applied to the centrifugal blower after the centrifugal blower is installed can be detected by the air volume, and the movable part can be automatically operated, and a decrease in blowing efficiency and an increase in noise can be suppressed. A centrifugal blower is obtained.

  Another means is a centrifugal blower characterized in that it includes a rotational speed detection means for detecting the rotational speed of the centrifugal blower, and automatically adjusts the position of the movable portion in accordance with the detected rotational speed.

  By this means, a change in static pressure applied to the centrifugal fan after the centrifugal fan is installed can be detected by the number of rotations, and the movable part can be automatically operated, and a decrease in blowing efficiency and an increase in noise can be suppressed. A centrifugal blower that can be obtained is obtained.

  According to another aspect of the invention, the power unit is an electric motor, the electric unit includes an electric characteristic detection unit that detects an electric characteristic of the electric motor, and the position of the movable part is automatically adjusted according to the detected electric characteristic of the electric motor. A centrifugal blower is used.

  By this means, a change in static pressure applied to the centrifugal blower after the centrifugal blower is installed can be detected by the electric characteristics of the electric motor, and the movable part can be automatically operated, and a reduction in blowing efficiency and an increase in noise are suppressed. A centrifugal blower that can be obtained is obtained.

  ADVANTAGE OF THE INVENTION According to this invention, even if the static pressure added to a centrifugal blower changes, the centrifugal blower which suppresses the fall of ventilation efficiency and the raise of a noise can be provided.

Side sectional view which shows Hc maximum time of centrifugal blower of form 1 of premise of this invention Side sectional view which shows the time of Hc minimum of the centrifugal blower of form 1 of the premise of this invention Graph showing effect of centrifugal blower of form 1 of the premise of the present invention (a) Graph showing characteristic of centrifugal blower when Hc is fixed at maximum and minimum (b) Characteristic of centrifugal blower when Hc is movable Graph showing Side sectional view which shows Hc minimum time of the centrifugal blower of Embodiment 1 of this invention Side sectional view which shows Hc maximum time of the centrifugal blower of the reference form 1 of this invention Side sectional view which shows the time of Hc minimum of the centrifugal blower of the reference form 1 of this invention Side sectional view which shows the centrifugal blower of Embodiment 2 of this invention. Side sectional view showing a conventional centrifugal blower

The invention according to claim 1 of the present invention includes a power unit, a centrifugal impeller that rotates by the power unit and blows air, and a casing that includes the centrifugal impeller, and the casing is substantially parallel to the rotation shaft of the centrifugal impeller. A centrifugal blower having a peripheral wall, a suction side wall with a suction port, and an anti-suction side wall opposite to the suction side wall, wherein the casing has a movable part, and the internal volume of the casing can be changed. In an operating state where the static pressure applied to the centrifugal blower is small and the air volume is large, the internal volume of the casing is increased, and the flow path through which the flow that flows out of the centrifugal impeller is widened. In an operating state where the wind speed can be reduced and turbulence can be suppressed and the static pressure applied to the centrifugal blower is large and the air volume is small, the inner volume of the casing is reduced and the flow is biased in the casing. It generated can be suppressed that the turbulent flow is generated, an effect that even if the static pressure is added to the centrifugal blower is changed it is possible to suppress an increase of the drop and the noise of the blower efficiency. In addition, the centrifugal blower is characterized in that all or part of the suction side wall is movable in the direction of the rotation axis of the centrifugal impeller, and the position of the suction port can be adjusted in accordance with the change in the casing internal volume. A part of the flow that flows out of the centrifugal impeller in a state where the static pressure applied to the centrifugal blower is large and the air volume is small, flows into the centrifugal impeller again through the gap between the suction port and the centrifugal impeller to form a circulating flow It is possible to suppress this, and even if the static pressure applied to the centrifugal blower changes, there is an effect that it is possible to suppress a decrease in blowing efficiency and an increase in noise. In addition, the centrifugal blower is characterized in that a suction drum is provided in the suction port of the suction side wall, and the outer diameter of the suction drum is smaller than the inner diameter of the centrifugal impeller, and the static pressure applied to the centrifugal blower is large. When the suction side wall moves with the suction port so that the inner volume of the casing is reduced in a small operating state, the suction cylinder can enter the centrifugal impeller, and a part of the flow that flows out of the centrifugal impeller And the centrifugal impeller can be prevented from flowing into the centrifugal impeller again to form a circulating flow, and even if the static pressure applied to the centrifugal blower changes, the air blowing efficiency decreases and the noise increases. It has the effect that it can be suppressed.

  The centrifugal blower is characterized in that it has a detecting means for detecting the operation state of the centrifugal blower, and automatically adjusts the position of the movable portion according to the detected operation state of the centrifugal blower. Even if the static pressure applied to the centrifugal blower changes, the movable part can be automatically operated, and it is possible to suppress a decrease in blowing efficiency and an increase in noise.

  In addition, it is equipped with an air volume detection means that detects the air volume of the centrifugal fan, and automatically adjusts the position of the movable part according to the detected air volume, and is added to the centrifugal fan after the centrifugal fan is installed. It is possible to detect a change in the static pressure by the air volume and automatically operate the movable part, and to suppress a reduction in blowing efficiency and an increase in noise.

  In addition, the centrifugal blower includes a rotational speed detecting means for detecting the rotational speed of the centrifugal blower, and automatically adjusts the position of the movable portion according to the detected rotational speed. A change in static pressure applied to the blower can be detected based on the number of rotations, and the movable part can be automatically operated. This has the effect of suppressing a decrease in blowing efficiency and an increase in noise.

  Further, the centrifugal fan according to the present invention is characterized in that the power part is an electric motor, and includes an electric characteristic detection means for detecting the electric characteristic of the electric motor, and the position of the movable part is automatically adjusted according to the detected electric characteristic of the electric motor. The change of static pressure applied to the centrifugal fan after the centrifugal fan is installed can be detected by the electric characteristics of the motor, and the movable part can be automatically operated, suppressing the decrease in the blowing efficiency and the increase in noise. It has the effect of being able to.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

( Premise form 1)
A premise mode 1 of the present invention will be described with reference to FIGS. As shown in the figure, a centrifugal blower 1 used as a ceiling-embedded ventilation fan attached to a ceiling for ventilating a space such as a bathroom or a toilet has a lower surface opened and a duct connection opening 3 on a side surface 2. An electric motor 6 having a rotating shaft 5 and having a diameter of 75 mm and a height of 80 mm in an outer shell 4 having a 258 mm square and a height of 198 mm, and a multi-blade centrifugal impeller fixed to the rotating shaft 5 of the electric motor 6 so as to be rotatable. 7 and a casing 8 so as to surround the centrifugal impeller 7.

  The centrifugal impeller 7 includes a main plate 14 fixed to the electric motor 6, a plurality of (50 sheets) annularly arranged on the outer peripheral side of the main plate 14, a blade outer diameter of 182 mm, a blade inner diameter of 155 mm, and a blade in the direction of the rotary shaft 5 A blade 15 having a length of 60 mm is provided, and a blade tip portion 16 of the blade 15 is supported by an annular plate 17 attached to the outer periphery.

  The casing 8 is in the shape of a bell mouth facing the outer shell 4 and has a suction side wall 10 having a suction port inner diameter of 155 mm and having a suction port 9 concentric with the rotary shaft 5, and is opposed to the suction side wall 10 with a distance Hc. A fixed anti-suction side wall 11 and an outer peripheral wall 12 which is spiral and substantially parallel to the rotation shaft 5 and is integral with the suction side wall 10, and the outer peripheral wall 12 communicates with the duct connection opening 3 of the outer shell 4. It has.

  The suction side wall 10 includes a suction port portion 20 and a suction port outer peripheral portion 21, and the outer peripheral wall 12 includes a fixed portion 18 and a movable portion 19 integrated with the suction port outer peripheral portion 21 of the suction side wall 10. 6, the distance Hc can be changed from 70 mm to 110 mm by sliding in the direction of the rotation axis 5 (hereinafter referred to as the rotation axis direction).

  With this configuration, by applying a driving force to the rotating shaft 5 from the electric motor 6 and rotating the centrifugal impeller 7, the suction air passes through the suction port 9, flows into the blade 15, is pressurized, and flows out from the blade 15. Further, when passing through the casing 8, the dynamic pressure is gradually converted into a static pressure and discharged from the discharge port 13 to the outside.

  At this time, in an operation state in which the static pressure applied to the centrifugal blower 1 is small and the air volume is large, as shown in FIG. 1, the movable portion 19 is set to a position where the distance Hc is maximum within the movable range (Hc = 110 mm). As a result, the internal volume of the casing 8 can be increased, the flow path through which the flow flowing out from the centrifugal impeller 7 can be widened, the wind speed can be reduced, and the occurrence of turbulence can be suppressed. In an operation state in which the static pressure applied to the cylinder is large and the air volume is small, as shown in FIG. 2, the movable portion 19 is set to a position where the distance Hc is minimum within the movable range (Hc = 70 mm). It is possible to suppress the occurrence of turbulent flow by generating a biased flow in the casing 8 by reducing the internal volume, and even if the static pressure applied to the centrifugal blower changes, the reduction in blowing efficiency and noise Can suppress the rise of That.

  Further, since the movable portion 19 is a part of the suction port outer peripheral portion 21 and the outer peripheral wall 12 of the suction side wall 10, the centrifugal impeller 7 viewed from the direction of the rotation axis that is a factor that determines the basic characteristics of the centrifugal blower 1. The inner volume of the casing 8 can be changed while keeping the positional relationship between the shape of the casing 8 and the casing 8 constant, and the reduction of the blowing efficiency and noise of the centrifugal fan 1 due to the change of the inner volume can be suppressed. Even if the applied static pressure changes, it is possible to suppress a decrease in blowing efficiency and an increase in noise.

  Further, the relative positional relationship between the suction port 9 of the suction side wall 10 and the centrifugal impeller 7 can be always maintained, and the gap 22 between the suction port 9 and the centrifugal impeller 7 can be kept constant. It is possible to prevent a part of the flow that has flown out from flowing into the centrifugal impeller 7 again from the gap 22 between the suction port 9 and the centrifugal impeller 7 to form a circulating flow, and the static pressure applied to the centrifugal fan 1 Even if the air pressure changes, it is possible to suppress a decrease in blowing efficiency and an increase in noise.

  FIG. 3 shows a graph comparing the air volume-static pressure characteristics and noise characteristics of the centrifugal blower 1 of the present invention.

  The solid line A in the graph of FIG. 3A shows the air flow-static pressure characteristics when the distance Hc between the suction side wall 10 and the anti-suction side wall 11 is fixed to the maximum, and the solid line B shows the noise characteristics at that time. A broken line A shows the air flow-static pressure characteristic when the distance Hc is fixed to the minimum, and a broken line B shows the noise characteristic at that time. When the distance Hc is the maximum, that is, when the internal volume of the casing 8 is the maximum, when the distance Hc is the minimum, that is, when the internal volume of the casing 8 is the minimum, the same is true when the static pressure is low and the air volume is large. It can be seen that the air volume is large even at static pressure, the air blowing efficiency is good, and the noise is low. On the other hand, when the static pressure is high and the air volume is small, it can be seen that when the distance Hc is the minimum, that is, when the internal volume of the casing 8 is the minimum, the air volume is large even with the same static pressure, and the blowing efficiency is good. It can be seen that it is low.

The graph of FIG. 3B is a graph in the case where the distance Hc between the suction side wall 10 and the anti-suction side wall 11 is changed by moving the movable part 19, and the solid line A shows the air volume-static pressure characteristics, and the solid line B shows the noise characteristics. Indicates. Figure 3 distance Hc is the largest and shown to suction inclusive sidewall 10 in (a) anti-suction sidewall 11, as compared with when it is fixed at a minimum, by changing the distance Hc by the movable portion 19, added to the centrifugal blower 1 Even if the static pressure changes and the air volume changes, it can be seen that the air blowing efficiency is good and the noise is low.

  In the first embodiment, the inner volume of the casing 8 is changed by changing the distance Hc between the suction side wall 10 and the anti-suction side wall 11 of the casing 8, but the outer wall 12 of the casing 8 as viewed from the rotation axis direction is changed. The same effect can be obtained even when the volume of the casing 8 is changed by changing the spiral shape.

(Embodiment 1 )
The same parts as those in the premise mode 1 are denoted by the same reference numerals, and detailed description thereof is omitted. In the second embodiment of the present invention, as shown in FIG. 4, the suction side wall 10 is provided with a suction drum 23 at the suction port portion 20, and the outer peripheral wall 12 is a movable portion integrated with the fixed portion 18 and the entire suction side wall 10. 19, the movable portion 19 is slid in the direction of the rotation axis, the distance Hc can be changed from 70 mm to 110 mm, and the outer diameter of the suction drum 23 is smaller than the inner diameter 155 mm (148 mm) of the centrifugal impeller 7. .

  With this configuration, in a state where the static pressure applied to the centrifugal blower is large and the air volume is small, the movable portion 19 is set to a position where the distance Hc is minimum within the movable range (Hc = 70 mm). By reducing the internal volume, it is possible to suppress the occurrence of a turbulent flow due to the occurrence of a biased flow in the casing 8, and the suction drum 23 can enter the centrifugal impeller 7. 7 can be prevented from flowing into the centrifugal impeller 7 again through the gap 22 between the suction port 9 and the centrifugal impeller 7 to form a circulating flow, and is added to the centrifugal blower 1. Even if the static pressure changes, it is possible to suppress a decrease in blowing efficiency and an increase in noise.

( Reference form 1 )
The same parts as those in the first embodiment and the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Embodiment 1 Reference of the present invention, as shown in FIGS. 5 and 6, outside the interior of the centrifugal impeller 7 of the casing 8, a spiral-like partition plate 24 and the centrifugal separating the interior of the casing 8 in the direction of the rotational axis A movable part 19 having a cylindrical part 25 surrounding the impeller is provided, and the volume between the suction side wall 10 of the casing 8 and the partition plate 24 of the movable part 19 can be changed.

  With this configuration, the volume between the suction side wall 10 of the casing 8 and the partition plate 24 of the movable part 19 within the movable range in the operating state where the static pressure applied to the centrifugal blower 1 is small and the air volume is large. By setting the position at which the flow is maximized, the flow path through which the flow flowing out from the centrifugal impeller 7 passes can be widened to reduce the wind speed and suppress the occurrence of turbulence, and is added to the centrifugal blower 1. In an operation state in which the static pressure is large and the air volume is small, the movable part 19 is positioned within the movable range so that the volume between the suction side wall 10 of the casing 8 and the partition plate 24 of the movable part 19 is minimized. It is possible to suppress the occurrence of a turbulent flow due to the occurrence of a biased flow in the casing 8, and even if the static pressure applied to the centrifugal blower changes, it is possible to suppress a decrease in blowing efficiency and an increase in noise. Can also centrifuge The internal volume of the casing 8 can be changed while keeping the positional relationship between the shapes of the centrifugal impeller 7 and the casing 8 as seen from the direction of the rotation axis, which is a factor that determines the basic characteristics of the machine 1. It is possible to suppress a reduction in the air blowing efficiency and noise of the centrifugal blower 1 due to the change of.

  Further, since the partition plate 24 has a spiral shape, the flow path of the flow that flows out from the centrifugal impeller 7 gradually expands, so that the wind speed can be gradually reduced to suppress the occurrence of turbulence. Even if the static pressure applied to the blower changes, it is possible to suppress a decrease in blowing efficiency and an increase in noise.

  Moreover, when the movable part 19 moves so that the internal volume of the casing 8 becomes small in an operation state in which the static pressure applied to the centrifugal blower 1 is large and the air volume is small, the movable part 19 moves out of the flow flowing out from the centrifugal impeller 7. The cylindrical part 25 can prevent the flow that tends to flow out between the partition plate 24 of the part 19 and the anti-suction side wall 11 to suppress the generation of turbulent flow, and the static pressure applied to the centrifugal blower 1 changes. Moreover, the fall of ventilation efficiency and the raise of a noise can be suppressed.

  Although the movable portion 19 is the movable portion 19 including the spiral partition plate 24 that divides the inside of the casing 8 in the rotation axis direction and the cylindrical portion 25 that surrounds the centrifugal impeller, the partition plate 24 is anti-suction of the casing 8. The same effect can be obtained even with a configuration that forms part of the side wall 11.

(Embodiment 2 )
The same parts as those in the first embodiment, the first embodiment, and the first embodiment are given the same reference numerals, and detailed description thereof is omitted. In Embodiment 2 of the present invention, as shown in FIG. 7, a spiral partition plate 24 and a centrifugal impeller that divide the inside of the casing 8 in the direction of the rotation axis are provided outside the centrifugal impeller 7 inside the casing 8. A movable portion 19 having a surrounding cylindrical portion 25 and a stepping motor 26 for moving the movable portion 19 in the axial direction are provided. And an optimum position of the movable portion 19 is stored in advance for each wind speed value of the discharge port 13, and the operation of the stepping motor 26 is received in response to a signal from the hot-wire anemometer 27. The control circuit unit 28 that controls and adjusts the position of the movable unit 19 is provided.

  With this configuration, the position of the movable part 19 is automatically adjusted according to the wind speed detected by the hot-wire anemometer 27, that is, the air volume of the centrifugal blower 1, and the suction side wall 10 of the casing 8 and the partition plate 24 of the movable part 19 The volume between the two can be changed, and even if the static pressure applied to the centrifugal blower changes after the centrifugal blower is installed, it is possible to suppress a decrease in blowing efficiency and an increase in noise.

  Note that the same effect may be obtained by providing a rotational speed detection means for detecting the rotational speed of the centrifugal blower 1 instead of a means for detecting the air volume, and automatically adjusting the position of the movable portion 19 according to the detected rotational speed. Can be obtained. Examples of the rotation speed detection means include a laser tachometer and an electronic circuit that acquires a rotation signal of a DC motor.

  In addition, the same effect can be obtained even if an electric characteristic detecting means for detecting the electric characteristic of the electric motor 6 is provided and the position of the movable portion 19 is automatically adjusted according to the detected electric characteristic of the electric motor 6. Examples of the electric characteristic detection means include an electronic circuit that acquires electric characteristics such as current and voltage of a DC motor.

  The present invention provides a centrifugal blower that suppresses a decrease in blowing efficiency and an increase in noise even when the static pressure applied to the centrifugal blower changes, and is incorporated into various air conditioners, air conditioners, and home appliances. Can be used for blower.

DESCRIPTION OF SYMBOLS 1 Centrifugal blower 2 Side surface 3 Duct connection opening 4 Outer shell 5 Rotating shaft 6 Electric motor 7 Centrifugal impeller 8 Casing 9 Suction port 10 Suction side wall 11 Anti-suction side wall 12 Outer wall Hc Distance 13 Discharge port 14 Main plate 15 Blade 16 Blade tip 17 Annular plate 18 Fixed part 19 Movable part 20 Suction port part 21 Suction port outer peripheral part 22 Gap 23 Suction cylinder 24 Partition plate 25 Cylindrical part 26 Stepping motor 27 Hot wire anemometer 28 Control circuit part

Claims (5)

A power unit, a centrifugal impeller that is rotated by the power unit and blows air, and a casing that includes the centrifugal impeller, wherein the casing includes an outer peripheral wall substantially parallel to a rotation shaft of the centrifugal impeller, and a suction port A centrifugal blower provided with a suction side wall provided with an anti-suction side wall opposite to the suction side wall, provided with a movable part in the casing, and the internal volume of the casing can be changed ,
All or part of the suction side wall is movable in the direction of the rotation axis of the centrifugal impeller;
A centrifugal blower comprising a suction drum at the suction port of the suction side wall, wherein an outer diameter of the suction drum is smaller than an inner diameter of the centrifugal impeller . Comprising a detection means for detecting the operating state of the centrifugal blower, the detected centrifugal blower according to claim 1, wherein the automatically adjusting the position of the movable portion in accordance with the operating state of the centrifugal fan has. The centrifugal blower according to claim 2 , further comprising an air volume detecting means for detecting an air volume of the centrifugal blower, wherein the position of the movable portion is automatically adjusted according to the detected air volume. The centrifugal blower according to claim 2 , further comprising a rotational speed detection means for detecting the rotational speed of the centrifugal blower, wherein the position of the movable portion is automatically adjusted according to the detected rotational speed. In the power unit is an electric motor, comprising an electric characteristics detecting means for detecting an electrical characteristic of the electric motor, according to the position of the movable unit in accordance with electrical characteristics of the detected said motor in claim 2, characterized in that the automatic adjustment Centrifugal blower.

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