JP2015183947A - range hood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate maintenance by suppressing deterioration of a silence effect, even when an active muffler duct is installed in a range hood containing high-temperature and high-humidity soot generated in cooking.SOLUTION: In a range hood 1 including an active muffler duct 10, a central axis 14 of the active muffler duct is installed inclinedly to a central axis 15 of a body, an upper opening end part 17 of the active muffler duct 10 is a surface vertical to the central axis of the active muffler duct 10, and a lower opening end part 18 of the active muffler duct 10 is a surface parallel to the lower surface of the body 4.

Description

  The present invention relates to a range hood provided with an active silencer duct that is attached to an air passage of the range hood and silences noise generated during operation of the range hood.

  In recent years, range hoods installed in kitchens are 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 duct for a duct in a range hood.

  Conventionally, as an active silencer for a duct, as shown in the cross-sectional view of FIG. 6, a reference microphone 102 for an internal original sound and a silencer speaker 103 that are sequentially attached to the inside of the duct 101 at appropriate intervals from the upstream side. , An error microphone 104 and an arithmetic controller 105 connected to each of them are known (see, for example, Patent Document 1).

  In this type of device, the generated sound propagating in the duct 101 together with the air flow 106 is detected by the reference microphone 102, and the arithmetic controller 105 generates a signal having a phase opposite to that of the original sound. 103 cancels and silences the original sound emitted into the duct 101, the error microphone 104 monitors the internal sound, and the arithmetic controller 105 automatically adjusts the mute speaker 103 so that the output of the error microphone 104 becomes zero. doing.

  Thus, the active silencer for ducts silences the noise that is propagated by making the sound field one-dimensional (plane wave) by using the duct.

Japanese Utility Model Publication No. 5-11198

  However, in the device described in the above-mentioned conventional patent document 1, when mounted on a ventilation device such as a range hood, it is necessary to shorten the duct due to size restrictions, and the microphone generates a strong standing wave generated in the duct. There is a problem that the effect of the active silencer occurs at a specific frequency for detection.

  SUMMARY OF THE INVENTION The present invention solves the above-described conventional problems, and an object thereof is to provide a range hood that prevents a reduction in the effect of an active silencer at a specific frequency.

  In order to achieve the above object, the present invention has a rectangular parallelepiped main body installed above the cooking device and having a discharge port communicating with the outside on the top surface and a suction port for sucking air on the lower surface, and the lower surface. A hood that collects air containing oily smoke generated from below during cooking and guides it to the suction port, a ventilation fan and motor that exhausts the air inside the main unit to the outside, and a microphone ( In a range hood having an active silencer duct composed of a microphone) and a speaker, the central axis of the active silencer duct is inclined with respect to the central axis of the main body, and the upper opening end of the active silencer duct is the active silencer duct. The lower opening end of the active silencer duct is a plane parallel to the lower surface of the main body, thereby achieving the intended purpose. .

  ADVANTAGE OF THE INVENTION According to this invention, even if it installs an active silencer duct in the range hood containing the high temperature, high humidity oil smoke which generate | occur | produces at the time of cooking, it can be set as the structure which prevents the fall of the effect of an active silencer at a specific frequency. .

The block diagram which shows the side cross section of the range hood of Embodiment 1 of this invention Graph of the effect of the same range hood Outline side sectional view of the active silencer duct of the same range hood Outline perspective view of range hood of Embodiment 2 of the present invention The block diagram which shows the side cross section of the active sound deadening duct of the same range hood Sectional view showing a conventional active silencer duct

  The cooker hood according to claim 1 of the present invention is installed in the upper part of the cooking device, and has a rectangular parallelepiped main body having a discharge port communicating with the outside on the top surface and a suction port for sucking air on the lower surface, and cooking on the lower surface. A hood that collects air containing oily smoke that sometimes occurs from below and guides it to the suction port, a ventilation fan and motor that exhausts the air inside the unit to the outdoors, and a microphone (microphone) upstream of the ventilation fan motor ) And an active silencer duct comprising a speaker, the central axis of the active silencer duct is inclined with respect to the central axis of the main body, and the upper opening end of the active silencer duct is the active silencer duct. The surface is perpendicular to the central axis, and the lower opening end of the active silencer duct is a surface parallel to the lower surface of the main body.

  As a result, when the axial length of the active silencer duct is changed as compared with the case where the axial length is uniform, strong standing waves generated in the duct can be suppressed. The noise to be silenced can be detected with high accuracy, and a reduction in the silencing effect due to a standing wave of a specific frequency can be suppressed.

  In the range hood according to claim 2, the central axis of the active silencer duct is inclined so that the lower part of the active silencer duct is closer to the front side of the hood than the upper part.

  As a result, the strong standing wave generated in the duct can be suppressed, so that the microphone can accurately detect the noise to be silenced, and the deterioration of the silencing effect due to the standing wave of a specific frequency can be suppressed. Thus, the position of dirt in the duct can be easily confirmed from the position of the user, and the inside of the duct can be easily wiped off, so that maintainability can be improved.

  According to a third aspect of the present invention, the active silencer duct has a rectangular cross section, and the microphone is disposed on the surface where the axial length of the active silencer duct is maximized.

  As a result, the distance between the open end of the active silencer duct and the microphone can be secured, so that the microphone is separated from the noise source caused by the vortex generated when the airflow flows at the open end. The noise to be silenced can be detected with high accuracy and the reduction in the silencing effect can be suppressed.

  The range hood according to claim 4 is composed of a plurality of small-diameter ducts each having a rectangular cross section in which the active silencer duct is divided by a plane parallel to at least the inclined surface of the active silencer duct. The microphone is installed on a surface having the maximum axial length.

  Thereby, since the duct length of each small-diameter duct is different, the frequency of the standing wave generated in the duct is dispersed, and generation of a strong standing wave can be suppressed. Furthermore, by securing the distance between the small-diameter duct opening and the microphone, the microphone is separated from the noise source caused by the vortex generated when the airflow flows at the opening end. It is possible to detect with high accuracy and to suppress the reduction of the silencing effect.

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

(Embodiment 1)
As shown in the side view of the range hood in FIG. 1, the range hood 1 of the present embodiment is installed above the heating cooker and has a discharge port 2 communicating with the top surface outdoors and a suction port for sucking air into the lower surface. 3, a rectangular parallelepiped main body 4, a hood 5 that collects air containing smoke generated from below during cooking on the lower surface and guides it to the suction port 3, and ventilation that exhausts the air in the main body 4 to the outside. A fan 9, a motor 7, and a filter 9 that is installed near the suction port 3 in the air passage 8 and removes oil dust from the sucked air are provided.

  An active silencer duct 10 is provided inside the main body 4 upstream of the ventilation fan 6. The active silencer duct 10 is detected by a reference microphone 11 that detects noise propagating in the air passage 8 and a reference microphone 11. These are connected to a speaker 12 that emits sound in a phase opposite to the generated noise into the air passage 8 and an error microphone 13 that detects noise attenuated by the sound emitted from the speaker 12 into the air passage 8. It is comprised from the calculation controller (not shown) which always silences the noise of the fan 6.

  Here, the central axis 14 of the active silencer duct is installed to be inclined with respect to the central axis 15 of the main body, and the upper open end 17 of the active silencer duct 10 is a plane perpendicular to the central axis 14 of the active silencer duct. The lower opening end 18 of the active silencer duct 10 is shaped to be a surface parallel to the lower surface of the main body 4. In other words, the active silencer duct 10 is composed of two opposing inclined surfaces 19 and a trapezoidal surface 20 adjacent to these surfaces. It is assumed that all the airflow from the suction port 3 passes through the active silencer duct 10.

  That is, the upper opening end 17 and the lower opening end 18 are not parallel surfaces, so that the length of the side constituting the active silencer duct 10 is changed.

  That is, the active silencer duct 10 has a square cross-sectional shape in the horizontal direction, a plane having the maximum axial length and a plane having the minimum axial length, and two planes connecting them to change the axial length from the minimum to the maximum. Consists of The error microphone 13 is disposed on the surface 21 having the maximum axial length.

  In the first embodiment, the active silencer duct 10 has an axial maximum length A of 270 mm and a minimum length B of 240 mm.

  With the above configuration, the air sucked from the suction port 3 passes through the air passage 8 in the order of the filter 9, the active silencer duct 10, and the ventilation fan 6, and then exhausted from the discharge port 2 to the outside of the main body 4. . Since the active silencer duct 10 is provided, the fan noise accompanying the air blowing is reduced and radiated from the suction port 3 connected to the living room.

  Here, in the conventional technology, the axial length of the active silencer duct is uniform, and particularly when the length of the active silencer duct is about several tens of centimeters, a strong sound is determined in the duct. When a standing wave is generated and the standing microphone 11 or the error microphone 13 detects this standing wave, the fan noise that is the target of mute cannot be detected accurately, and the muffling effect is deteriorated.

  However, in the present invention, since the duct length changes at each cross-sectional position of the active silencer duct 10, the generation of a strong standing wave is mitigated, and the microphone can accurately detect the noise to be silenced and suppress the reduction in the silence effect. Will be able to.

  FIG. 2 shows an example of a graph of the effect of the present invention. FIG. 2 shows the result of a frequency response simulation when a sound source is arranged at the center of one end of the active silencer duct. As a comparative example, the conventional active silencer duct having a uniform edge at the lower opening is shown in FIG. The result of averaging the length of each side for the length of each side of the active silencer duct 10 of the present invention is shown.

  The conventional active silencer duct has a sharp peak in the vicinity of 260 Hz, indicating the presence of a strong standing wave, which degrades the effect of the active silencer duct. However, the active silencer duct of the present embodiment shows that the standing wave that appears as a peak can be alleviated, which leads to suppression of a decrease in the effect of the active silencer duct.

  Furthermore, as shown in FIG. 3, by providing an inclination in such a direction that the lower side of the active silencer duct 10 is closer to the front side of the range hood 1 than the upper side, oil droplets in the duct from the position of the user 22 As a result, it is easy to visually check the position of dirt such as 23, and in addition, the inside of the duct can be easily wiped off, so that maintenance can be facilitated.

  In addition, the error microphone 13 is disposed on the axial length maximum surface 21, and the distance between the lower opening end 18 and the error microphone 13 can be secured as compared with the case where the axial length is short. That is, since the error microphone 13 is separated from the noise source caused by the vortex generated at the lower opening end 18 when the airflow flows into the active silencer duct 10, the microphone can accurately detect the noise to be silenced, and the microphone It is possible to suppress the deterioration of the silencing effect due to the acquisition of the noise signal.

  In addition, although the range hood 1 of Embodiment 1 arrange | positions all of the reference microphone 11, the speaker 12, and the error microphone 13 in the axial length maximum surface 21, these are arrange | positioned on a separate surface. For example, in order to prevent the vortex of the airflow generated by unevenness such as the error microphone 13 arranged on the upstream side of the airflow and the connection parts of the speaker 12 from being detected as noise by the reference microphone 11 arranged downstream. By disposing the reference microphone 11 on the other surface, it is possible to suppress a decrease in the silencing effect.

(Embodiment 2)
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  FIG. 4 and FIG. 5 show an active silencer duct 24 of Embodiment 2 provided in the range hood 1 in place of the active silencer duct 10.

  The active silencer duct 24 desirably has a small duct width in order to widen the target frequency associated with the target frequency ≦ sound speed ÷ (2 × duct width). However, if the duct width is reduced, the air passage becomes narrower and a sufficient air volume cannot be obtained. Therefore, the active silencer duct 24 is composed of a plurality of small-diameter ducts having a rectangular cross section divided at least by a plane parallel to the inclined plane 19 of the active silencer duct.

  As an example, as shown in FIG. 4, the active silencer duct 24 is divided into four small-diameter ducts in order to suppress ventilation resistance. That is, the active silencer duct 24 has a configuration in which the first small-diameter duct 25, the second small-diameter duct 26, the third small-diameter duct 27, and the fourth small-diameter duct 28 are arranged in a lattice pattern. The small diameter duct 27 is disposed on the front side of the range hood 1, and the second small diameter duct 26 and the fourth small diameter duct 28 are disposed on the back side. Further, the axial maximum length and the minimum length of the first small diameter duct 25 and the third small diameter duct 27 are equal, and the axial maximum length and the minimum length of the second small diameter duct 26 and the fourth small diameter duct 28 are equal. . That is, the maximum axial length a of the first small diameter duct 25 and the third small diameter duct 27 is larger than the maximum axial length b of the second small diameter duct 26 and the fourth small diameter duct 28.

  In addition, an error microphone is installed on the surface having the maximum axial length in each small-diameter duct. That is, as shown in FIG. 5, the error microphone 29 of the first small-diameter duct is disposed on the surface 31 having the maximum axial length of the first small-diameter duct, and the error microphone 30 of the second small-diameter duct is the axial direction of the second small-diameter duct. It is arranged on the longest surface 32. The first small-diameter duct 25 and the second small-diameter duct 26 and the third small-diameter duct 27 and the fourth small-diameter duct 28 which are disposed on the object have the same configuration (not shown).

  With the above configuration, in each small-diameter duct, the duct length changes at each cross-sectional position, so that it is possible to suppress the generation of a strong standing wave. Further, in the active silencing duct 24 as a whole, Because the length of the small-diameter ducts is different, the frequency band of the standing waves that can be generated can be dispersed, which has the effect of further mitigating standing waves, and the microphone can accurately detect the noise to be silenced, and the silencing effect It will be possible to suppress the decrease in.

  Further, since the error microphone is installed on the surface having the maximum axial length in each of the small-diameter ducts, the lower opening end 18 and the error microphone are installed in comparison with the case where the error microphone is installed on the surface having the short axial length. The distance between can be secured. That is, since the error microphone is separated from the noise source caused by the vortex generated at the lower opening end 18 when the airflow flows into the active silencer duct 24, the microphone can accurately detect the noise to be silenced, and the microphone It is possible to suppress the deterioration of the silencing effect caused by acquiring the signal.

  Also in the present embodiment, an oil drop in the duct from the position of the user 22 is provided by inclining in such a direction that the lower side of the active silencer duct 24 is closer to the front side of the range hood 1 than the upper side. Needless to say, it is easy to visually check the position of dirt such as 23, and the inside of the duct can be easily wiped off, so that maintenance can be facilitated.

  The range hood according to the present invention includes oil smoke because it can suppress deterioration of the noise reduction effect and facilitate maintenance even if an active noise reduction duct is installed in the range hood including high-temperature and high-humidity smoke generated during cooking. It is useful as a silencer mounted on a ventilator under the environment.

DESCRIPTION OF SYMBOLS 1 Range hood 2 Discharge port 3 Suction port 4 Main body 5 Hood 6 Ventilation fan 7 Motor 8 Air path 9 Filter 10 Active silencer duct 11 Reference microphone 12 Speaker 13 Error microphone 14 Central axis 17 of active silencer duct Upper center axis 17 of main body Open end 18 Lower open end 19 Inclined surface 20 Trapezoidal surface 21 Maximum axial length surface 24 Active silencer duct 25 First small diameter duct 26 Second small diameter duct 27 Third small diameter duct 28 Fourth small diameter duct 29 First Error microphone 30 for one small diameter duct Error microphone 31 for the second small diameter duct Maximum surface length in the axial direction of the first small diameter duct 32 Maximum surface length in the axial direction of the second small diameter duct

Claims (4)

A rectangular parallelepiped main body that is installed above the heating cooker and has a discharge port communicating with the outside on the top surface and a suction port for sucking air on the bottom surface, and collects air containing oil smoke generated from below when cooking on the bottom surface And a hood that guides the suction port,
A ventilation fan and a motor for exhausting the air in the main body to the outside;
In the range hood provided with an active silencing duct composed of a microphone (microphone) and a speaker on the upstream side of the ventilation fan motor,
The central axis of the active silencer duct is installed to be inclined with respect to the central axis of the main body,
The upper opening end of the active silencer duct is a surface perpendicular to the central axis of the active silencer duct, and the lower opening end of the active silencer duct is a surface parallel to the lower surface of the main body. A range hood characterized by that. The range hood according to claim 1, wherein the central axis of the active silencer duct is inclined so that the lower side of the active silencer duct is closer to the front side of the hood than the upper side. The range hood according to claim 1 or 2, wherein a cross-section of the active silencer duct is rectangular, and a microphone is disposed on a surface where the axial length of the active silencer duct is maximum. The active silencer duct is composed of a plurality of small diameter ducts each having a rectangular cross section divided by a plane parallel to the inclined surface of the active silencer duct, and each of the small diameter ducts includes a microphone and a speaker, and the microphone is in the axial direction. 3. The range hood according to claim 1, wherein the range hood is installed on a surface having a maximum length.

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