JP6600813B2 - Blower - Google Patents

Description

  The present invention relates to an air blower including an active silencer that is disposed in an internal air passage and silences noise generated during operation.

  In recent years, in air blowers such as air conditioners and ventilation fans, it has been required to reduce noise generated during operation. As one of means for solving such a problem, there is a method of mounting an active silencer having a duct configuration in an internal air passage.

  2. Description of the Related Art Conventionally, as this type of active silencer, there is known an apparatus in which a microphone is provided with a space provided at a relatively slow position of the airflow in order to reduce the influence of the airflow in the air passage (see, for example, Patent Document 1). .

  The active silencer will be described below with reference to FIGS.

Conventionally, as an active silencer having a duct configuration, an internal original sound reference microphone 111, a silencer speaker 112, an error microphone, and the like, which are sequentially provided at appropriate intervals from the upstream side inside a rectangular duct 101 made of a thin steel plate, respectively. It is known that the computer is composed of 113 and an arithmetic controller 102 to which these are connected. In this case, as shown in FIG. 8 , in the case of the square duct 101, the microphone section 104 is provided at the corner, and the reference microphone 111 and the error microphone 113 are respectively provided.

  In this type of apparatus, a sound wave propagating in the rectangular duct 101 together with the air flow 103 is detected by the reference microphone 111. In the arithmetic and control unit 102, a signal having an opposite phase is created using the sound wave as an original sound, and the signal is emitted from the muffling speaker 112 into the square duct 101 as an opposite phase sound wave. The sound wave having the opposite phase exhibits a silencing effect on the original sound. The error microphone 113 monitors the sound in the rectangular duct 101 on the downstream side of the sound wave propagating from the muffling speaker 112, and the arithmetic controller 102 makes the output of the error microphone 113 zero from the monitor sound. The opposite phase signal is adjusted.

  As a result, the reference microphone 111 and the error microphone 113 do not detect the noise generated by the airflow in the duct, and can accurately detect only the noise original sound to be silenced, and the silencer feedback function is provided. improves.

Japanese Utility Model Publication No. 5-11198

  However, in the device described in Patent Document 1, since the size of the device is limited, in order to enclose the duct (rectangular duct 101) in the blower body, the duct is shortened to a practical length. There is a need. In the blower housing, the duct has a wind path that expands beyond the downstream end of the air flow, that is, a suddenly expanded wind path, and a vortex is generated at the downstream end of the duct. When the downstream end portion of the duct and the reference microphone that is the downstream microphone of the airflow are close to each other, the reference microphone picks up the noise generated by the vortex. That is, in detecting the original sound of the noise propagating in the duct, there is a problem that the vortex becomes noise and a sufficient silencing effect cannot be obtained.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object of the present invention is to provide a blower device that is less affected by vortices generated at the downstream end portion of a duct and improves the silencing effect.

An air blower according to the present invention includes an active silencer having a centrifugal fan that sucks air from an intake port provided perpendicular to a rotation shaft, and a cylindrical active silencer air passage disposed upstream of the intake port of the centrifugal fan. And an expansion space that includes the centrifugal fan and the active silencer and connects the two. The active silencing air passage and the centrifugal fan are arranged such that the central axis and the rotation axis of the active silencing air passage are in a vertical and horizontal relationship. The active silencer is configured by arranging a speaker and a downstream microphone in this order on the side wall of the active silencer air passage from the upstream side of the airflow. The active silencing air passage has an inclination with respect to the central axis so that the length of the pair of opposing buses is the longest bus and the shortest bus in the bus along the central axis on the side wall. In other words, a downstream opening that is an opening on the downstream side of the airflow is formed. The virtual plane in contact with the longest generatrix and the rotation axis are arranged to be parallel in the direction of the rotation axis. The downstream microphone is arranged on the longest bus side and on the upstream side of the airflow from the end of the downstream opening on the shortest bus side, thereby achieving the intended purpose.

  According to the present invention, since the distance between the downstream microphone and the downstream opening can be separated from the predetermined range, the vortex generated at the end on the downstream side of the sensor microphone is kept away, and the influence is reduced, that is, A decrease in the silencing effect due to the standing wave can be suppressed.

Configuration outline diagram of blower device according to Embodiment 1 of the present invention The figure which shows arrangement | positioning of the centrifugal fan of the air blower which concerns on the same Embodiment 1. The figure explaining the definition of a cylinder in the first embodiment Partial enlarged view of the active silencer Side sectional view of the air blower according to Embodiment 2 The figure which shows the position of the downstream microphone of the air blower Configuration outline diagram of conventional active silencer Sectional view of a conventional active silencer

A blower according to the present invention includes a centrifugal fan that sucks air from an air inlet provided perpendicular to a rotating shaft, and an active silencer that has a cylindrical active sound deadening air passage disposed upstream of the air inlet of the centrifugal fan. And an expansion space that encloses the centrifugal fan and the active silencer and connects the two. The active silencing air passage and the centrifugal fan are arranged such that the central axis and the rotation axis of the active silencing air passage are in a vertical and horizontal relationship. The active silencer is configured by arranging a speaker and a downstream microphone in this order on the side wall of the active silencer air passage from the upstream side of the airflow. The active silencing air passage has an inclination with respect to the central axis so that the length of the pair of opposing buses is the longest bus and the shortest bus in the bus along the central axis on the side wall. In other words, a downstream opening that is an opening on the downstream side of the airflow is formed. The virtual plane in contact with the longest generatrix and the rotation axis are arranged to be parallel in the direction of the rotation axis. The downstream microphone is arranged on the longest bus side and on the upstream side of the airflow from the end of the downstream opening on the shortest bus side.

  As a result, the distance between the downstream microphone and the downstream opening can be separated from the predetermined range, so that the vortex generated at the end of the downstream microphone on the downstream side is kept away and the influence is reduced, that is, the adverse effect of noise is eliminated. Thus, the silencing effect can be increased.

  In addition, the active silencing air passage forms a downstream opening so that the longest bus and the shortest shortest bus of the pair of buses facing each other on the cylindrical side wall are the longest in the direction of the rotation axis of the centrifugal fan. By arranging the virtual plane in contact with the busbar and the rotation axis of the centrifugal fan to be parallel in the direction of this rotation axis, the longest busbar side can be installed in an empty space to avoid the centrifugal fan. Dimension expansion does not occur.

Furthermore, in the blowing device according to the present invention, the lower flow side opening, characterized in that the linear distance from the downstream end opening to the bottom flow microphone is formed so as to minimize on the longest bus .

  As a result, the distance from the downstream microphone to the downstream opening can be ensured, and the effect of moving away the adjacent vortex can be reliably obtained, and the noise reduction effect can be increased by eliminating the adverse effect of noise.

Furthermore, in the blowing device according to the present invention, the active silencer, two potential dynamic mute air passage and aligned integral air passage in parallel, the two active silencer air passage is closest to the respective shortest bus side It is characterized by being arranged .

  Thereby, since the air path width per one of the active silencing air paths can be reduced, a silencing effect up to a higher frequency can be obtained.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to FIG. FIG. 1 is a schematic configuration diagram of the blower.

  The blower device 1 according to the first embodiment has a substantially rectangular parallelepiped casing, and includes a suction port 2 positioned on the bottom surface side and an exhaust port 3 positioned on the top surface side. An active silencer 4, an expansion space 5, and a centrifugal fan 6 are provided inside the housing. The casing may be a cube.

  The suction port 2 is located at the most upstream (downward in FIG. 1) in the air flow direction of the blower 1 and is provided as an opening for sucking air from the outside of the blower 1.

  The exhaust port 3 is located on the most downstream side (upward in FIG. 1) in the airflow direction in the blower 1 and communicates with the discharge port 7 of the centrifugal fan 6.

  The centrifugal fan 6 sucks air upstream from the air inlet 8 and discharges air from the air outlet 3, thereby discharging air sucked from the air inlet 2 to the outside of the blower 1.

  The centrifugal fan 6 includes a circular multi-blade fan 10, a motor (not shown) that rotates the multi-blade fan 10, and a scroll casing 11 that encloses the multi-blade fan 10. The multiblade fan 10 includes a rotating shaft 12 that serves as a center of rotation.

  The scroll casing 11 has a shape in which a scroll plate 13 that gradually expands the air path on the outer periphery of the rotary shaft 12 and the multiblade fan 10 is sandwiched between two flat side surfaces 14.

  The discharge port 7 is located on the upper surface surrounded by the two side surfaces 14 and the scroll plate 13.

  The intake port 8 is provided on one side surface 14 perpendicular to the rotation shaft 12.

  The motor (not shown) is coaxial with the rotary shaft 12 and is disposed in a form embedded in the space inside the centrifugal fan 6. Moreover, the rotating shaft 12 is arrange | positioned substantially horizontal, ie, a horizontal direction.

  In such a configuration, the expansion space 5 is a space that includes and connects the centrifugal fan 6 and the active silencer 4. As shown in FIG. 2, the centrifugal fan 6 has the scroll plate 13 that gradually expands the air path as described above, and has an arcuate curved surface. In the substantially rectangular parallelepiped housing, an empty space 15 is formed between the scroll plate 13 and the wall surface of the housing. The active silencer 4 is disposed downstream of the suction port 2 and upstream of the suction port 8 of the centrifugal fan 6.

  The active silencer 4 includes a cylindrical active silencer air passage 16, a silencer speaker 17 that is a speaker disposed in the active silencer air passage 16, a sensor microphone 18 that is a downstream microphone, and an error microphone 19 that is an upstream microphone. And an arithmetic control unit 20. Note that the error microphone 19 that is an upstream microphone is necessary to improve the silencing performance, but is not necessarily essential.

  The active silencing air passage 16 has a hollow cylindrical shape, and the shape of the cross section 22 perpendicular to the direction of the central axis 21 of the cylinder, which is the flow direction of the airflow, is circular.

  The central axis 21 is arranged substantially vertically, that is, in the vertical direction. The active silencing air passage 16 is arranged so that the central shaft 21 and the rotary shaft 12 of the centrifugal fan 6 are in a vertical and horizontal relationship.

  In general, as shown in FIG. 3, a cylinder has two parallel straight lines “l” and “g” on a plane “h”, and when this plane is rotated about “l” as a central axis, The curved surface created by a certain “g” is the side surface.

  As shown in FIG. 1, the active silencing air passage 16 includes a downstream opening 23 that is an opening on the downstream side of the airflow, and an upstream opening 24 that is an opening on the upstream side of the airflow and located on the cylindrical bottom surface 25. The side wall 26 corresponding to the side surface is provided. In addition, with reference to the upstream opening 24, as shown in FIG. 4, in the bus on the side wall 26, the pair of opposing buses 27 have the longest bus 28 and the shortest bus 29 shortest. A downstream opening 23 is formed in the upper part. That is, the end 30 of the downstream opening 23 of the active silencing air passage 16 is a cut surface having an inclination with respect to the circular central axis 21 or the cross section 22.

  As shown in FIG. 1, the error microphone 19, the muffler speaker 17, and the sensor microphone 18 are sequentially provided from the upstream side in the air flow direction of the active muffler air passage 16.

  As shown in FIG. 4, the sensor microphone 18 is disposed on the side of the longest bus 28 on the side wall 26 and on the upstream side of the airflow from the end 30 of the downstream opening 23 on the side of the shortest bus 29.

  Further, by arranging the sensor microphone 18 on the longest bus 28 and adjusting the shape of the end 30, the linear distance 31 on the longest bus 28 from the sensor microphone 18 to the end 30 of the downstream opening 23 is It is made to become the minimum in the linear distance 32 to the edge part 30 of the other downstream opening 23. FIG.

  As an example, the active silencing air passage 16 has a downstream opening 23 as a cut surface that cuts a cylinder at an angle smaller than 45 degrees with respect to the cross section 22 and an angle larger than 0 degrees, and the sensor microphone 18 has a linear distance. This can be realized by making the distance 31 equal to the diameter of the cylinder.

  An error microphone 19, a mute speaker 17, and a sensor microphone 18 are connected to the arithmetic control unit 20.

  As shown in FIGS. 1 and 4, the active silencing air passage 16 is arranged so that the virtual plane 33 in contact with the longest bus line 28 and the rotary shaft 12 are parallel to each other in the direction of the rotary shaft 12.

  The active silencing air passage 16 is provided on the downstream side of the suction port 2 so that the upstream opening 24 of the active silencing air passage 16 and the suction port 2 communicate with each other.

  As already described with reference to FIG. 1, the expansion space 5 is a space that includes the centrifugal fan 6 and the active silencer 4 and connects them. That is, an expansion space 5 that connects the downstream opening 23 of the active silencing air passage 16 and the centrifugal fan 6 is provided downstream of the active silencing air passage 16. The cross section 34 of the expansion space 5 is larger than the cross section 22 of the active silencing air path 16, and the air path rapidly expands from the downstream opening 23 of the active silencing air path 16 to the expansion space 5.

  The active silencing air passage 16 is positioned in the empty space 15 near the scroll plate 13 by inclining the downstream opening 23 in the enlarged space 5.

  In the above configuration, when the centrifugal fan 6 of the blower 1 is operated, an air flow from the suction port 2 to the exhaust port 3 is generated. At the same time, the noise of the centrifugal fan 6 is radiated from the suction port 2 through the expansion space 5 and the active silencing air passage 16.

  Since the active silencing air passage 16 has an effect on a plane wave in which the sound pressure is uniform in the cross-sectional direction, the sound pressure propagates one-dimensionally in the air passage.

  First, in the active silencing air passage 16, the sensor microphone 18 detects noise, and transmits the detected noise to the arithmetic control unit 20 as a noise signal.

  Next, the calculation control unit 20 first predicts a sound at the muffler point 35 assumed upstream of the muffler speaker 17 based on the sound detected by the sensor microphone 18.

  The enlarged view on the end 30 side in FIG. 4 is a case where the centrifugal fan 6 is sucking air in the enlarged space 5 (from above FIG. 4). That is, the airflow flows in the direction from the error microphone 19 toward the sensor microphone 18, and is discharged from the downstream opening 23 of the active silencing air passage 16 into the expansion space 5. In general, when the air current is discharged into a space where the air current expands, a vortex 36 is generated at the end 30 of the air path. Since the vortex 36 is accompanied by a pressure change and generates a sound, it is detected by the sensor microphone 18.

  In the blower device 1 according to the present embodiment, the sensor microphone 18 is disposed on the longest bus 28 side and on the upstream side of the airflow with respect to the downstream opening 23 on the shortest bus 29 side.

  As a result, the distance between the sensor microphone 18 and the end portion 30 can be separated from the predetermined range, so that the vortex 36 generated at the end portion 30 on the downstream side of the sensor microphone is moved away, and the influence is reduced, that is, noise is reduced. The noise reduction effect can be increased by eliminating adverse effects.

  Further, by arranging the sensor microphone 18 on the longest bus 28 and adjusting the shape of the end 30, the linear distance 31 on the longest bus 28 from the sensor microphone 18 to the end 30 of the downstream opening 23 is It is made to become the minimum in the linear distance 32 to the edge part 30 of the other downstream opening 23. FIG.

  That is, in the air blower 1, by making the linear distance 32 longer than the linear distance 31, the distance between the sensor microphone 18 and the end 30 can be secured, and the effect of keeping away the adjacent vortex can be reliably obtained. The noise reduction effect can be increased by eliminating the adverse effects of noise.

  Further, the active silencing air passage 16 is positioned in an empty space near the scroll plate 13 by inclining the downstream opening 23 with respect to the central axis 21 in the enlarged space 5, that is, sucking air from the axial direction. Since it arrange | positions in the position which does not block the suction | inhalation airflow of the centrifugal fan 6 to perform, ventilation performance is not reduced. In addition, the size expansion of the blower can be minimized.

  Now, the sound prediction at the muffing point 35 is performed based on the correlation between the sensor microphone 18 and the error microphone 19 obtained in advance when the error mike 19 is provided at the muffling point 35. Next, an inverted phase signal for canceling the predicted sound is generated, and this signal is generated as a canceling sound from the mute speaker 17 to be silenced. Further, in order to prevent the sound that arrives at the error microphone 19 from being shifted from the predicted sound and the noise reduction effect is reduced, the sound detected by the error microphone 19 is transmitted to the calculation control unit 20, so that the calculation control unit 20 Correct the predicted sound. Thereby, the silencing performance is improved. In this mechanism, the higher the correlation between the sound detected by the sensor microphone 18 and the sound detected by the error microphone 19, the higher the muffling effect.

  By the way, in order to increase the correlation, it is necessary that the same sound as the sound detected by the sensor microphone 18 is transmitted to the error microphone 19. However, for example, when a sound that can be heard only by one microphone is generated, the correlation is lowered. One of the causes for reducing this correlation is “standing wave” generated due to the generation of “vortex” at the end 30 and the length of the wind path.

  As already described with reference to the enlarged view on the end 30 side of FIG. 4, the centrifugal fan 6 is sucking air in the enlarged space 5 (from the upper side of FIG. 4). That is, the airflow flows in the direction from the error microphone 19 to the sensor microphone 18, is discharged from the downstream opening 23 of the active silencing air passage 16 to the expansion space 5, and a vortex 36 is generated at the end 30 of the air passage. The vortex 36 generates a small noise and can be detected by the sensor microphone 18, but becomes a noise signal that cannot be detected by the error microphone 19 located farther away from the sensor microphone 18. In other words, the presence of the vortex 36 reduces the correlation between the sensor microphone 18 and the error microphone 19, so that the silencing effect is also reduced.

  Further, the boundary between the active silencing air passage 16 and the expansion space 5 is an opening that suddenly expands. In such an opening, a standing wave is generated in the active silencing air passage 16 and the sound is amplified or attenuated, thereby reducing the correlation between the position of the sensor microphone 18 and the position of the error microphone 19. Will occur. For example, when a strong standing wave antinode is located at the position of the sensor microphone 18 and a strong standing wave node corresponds to the position of the error microphone 19, the correlation is greatly reduced. However, the downstream opening 23 is formed so that the longest bus 28 and the shortest shortest bus 29 have the longest pair of buses 27 facing each other on the bus 26 on the side wall 26 with respect to the upstream opening 24. Further, the length from the suction port 2 to the end portion 30 of the active silencing air passage 16 is made nonuniform at the end portion 30 of the upstream opening 24 by making the downstream opening 23 inclined. That is, the influence of the standing wave can be reduced by suppressing the generation of a strong standing wave. As a result, the correlation between the position of the sensor microphone 18 and the position of the error microphone 19 can be increased, and the silencing effect can be increased.

  In the present embodiment, the error microphone 19, the muffler speaker 17, and the sensor microphone 18 are arranged on the same straight line in the direction of the central axis 21, but the error microphone 19 and the mute speaker 17 are connected to the downstream opening 23. Since the distance is sufficiently secured and not easily affected by the vortex, the same effect can be obtained even if they are not arranged in the same straight line.

(Embodiment 2)
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, detailed description thereof will be omitted, and description will be made with reference to FIGS . 5 and 6 .

  As shown in the sectional side view of the air blower in FIG. 5, the air blower 37 according to the second embodiment has active silencing air passages 38 and 39 in which the end 30 downstream opening 23 is inclined with respect to the central axis 21. It is provided adjacent to the unit.

  Similarly to the active silencing air passage 16 of the first embodiment, the active silencing air passages 38 and 39 are cylinders having a circular central axis 21. Further, the active silencing air passages 38 and 39 are arranged so that the virtual plane 33 in contact with the longest bus 28 and the rotary shaft 12 are parallel to each other in the direction of the rotary shaft 12. In addition, the longest bus line 28 of each air path is arrange | positioned on the outer side. In other words, the two active silencing air paths 38 and 39 are arranged closest to each other on the shortest bus 29 side. In other words, in the present embodiment, the active silencing air passage is composed of two air passages, the active silencing air passage 38 and the active silencing air passage 39.

  The lower limit frequency of the sound to which active muffling can be applied in the duct is determined by the formula of sound speed ÷ (2 × wind path width). According to this formula, the silencing frequency range can be expanded by dividing and reducing the wind path width per one wind path.

As shown in FIG. 6, in the active silencing air passages 38 and 39, the sensor microphone 18 is installed on the longest bus 28 and upstream of the downstream opening 23 on the shortest bus 29 side in the direction of the central axis 21. ing. Further, the sensor microphone 18 is disposed on the longest bus 28, and the downstream opening 23 is set so that the linear distance 31 to the end 30 of the downstream opening 23 is smaller than the linear distance 32 to the other end 30. The shape is adjusted. As a result, the vortex 36 at the end 30 can be moved away from the sensor microphone 18 by a predetermined distance or more, and the influence of the standing wave can be mitigated. The effect can be increased.

  Moreover, since the downstream opening 23 can be positioned in the left and right empty spaces of the scroll plate 13 by inclining the downstream opening 23 with respect to the central axis 21, the air blowing performance is deteriorated by inhibiting the flow to the intake port 8. There is no. In addition, the size expansion of the blower can be minimized.

  Note that the error microphone 19 that is an upstream microphone is necessary to improve the silencing performance, but is not necessarily essential. In this case as well, the vortex 36 generated at the end 30 on the downstream side of the sensor microphone 18 is similarly moved away, and an effect of increasing the silencing effect is obtained.

  The air blower according to the present invention can suppress a decrease in the silencing effect even if it is installed in an air flow field built in an air conditioner or a ventilation fan, etc. This is useful as an active silencer that can suppress a decrease in the silencing effect.

DESCRIPTION OF SYMBOLS 1 Air blower 2 Suction port 3 Exhaust port 4 Active silencer 5 Expansion space 6 Centrifugal fan 7 Discharge port 8 Intake port 10 Multiblade fan 11 Scroll casing 12 Rotating shaft 13 Scroll plate 14 Side 15 Empty space 16 Active silencer air path 17 Silencer Speaker 18 Sensor microphone 19 Error microphone 20 Arithmetic control unit 21 Central axis 22 Cross section 23 Downstream side opening 24 Upstream side opening 25 Bottom surface 26 Side wall 27 A pair of bus lines 28 The longest bus line 29 The shortest bus line 30 The end part 31 The linear distance 32 The linear distance 33 The virtual plane 34 Cross section 35 Silencing point 36 Vortex 37 Blower 38, 39 Active silencing air path

Claims (3)

A centrifugal fan that takes in air from an air inlet provided perpendicular to the rotation axis ;
An active silencing device having a cylindrical active silencing air passage disposed upstream of the intake port of the centrifugal fan ;
A blower device comprising: the centrifugal fan and the active silencer; and an enlarged space for connecting the two ,
The active silencing air path and the centrifugal fan are arranged in a vertical and horizontal relationship with a central axis of the active silencing air path and the rotation axis,
The active silencer device, on the side walls of the active silencer air passage is constructed by arranging the upstream side by squirrels speaker and downstream microphone airflow in this order,
Wherein the active silencer air path, in the central axis generating line along on the side wall, with respect to the central axis such that the length of the pair of bus bars opposing becomes the shortest shortest generatrix longest longest generatrix An opening formed with an inclination, and a downstream opening that is an opening on the downstream side of the airflow is formed ;
The longest and the virtual plane tangent to the generatrix the axis of rotation and are arranged in parallel in the direction of the rotary shaft,
The said downstream microphone is arrange | positioned in the upstream of the airflow rather than the edge part of the said downstream opening part on the said longest bus line side and the said shortest bus line side. The downstream opening, the blowing device according to claim 1, characterized in that the linear distance from an end portion of the downstream opening to said downstream microphone is formed so as to minimize on the maximum bus. The active silencer comprises two active silencer air paths arranged in parallel to form an integrated air path ,
Two of the active silencer air passage, the air blowing device according to claim 1, characterized in that it is disposed adjacent each of said shortest bus side.