JP2003232295A - Centrifugal fan and cooker equipped with the centrifugal fan - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a centrifugal fan and a cooker equipped with the centrifugal fan of low noise with high blasting efficiency by suppressing the separation of an air current at the suction surface of a blade of a conventional centrifugal fan. <P>SOLUTION: An inflow edge 5a of the blade 5 of this centrifugal fan 1 is provided with a projecting part formed by either one of a recessed part and a projecting part, and the separation of an air current at the suction surface of the blade is suppressed by a vertical vortex formed by the projecting part. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal fan and a heating cooker equipped with the centrifugal fan.

[0002]

2. Description of the Related Art A conventional centrifugal fan 1 will be described below with reference to FIGS. As shown in FIG. 18, a conventional centrifugal fan 1 includes a rotating shaft 3 of a drive motor 2 and a main plate 4 which is connected to the rotating shaft 3 at its center and is rotationally driven.
And a plurality of blades 5 arranged on the outer periphery of the main plate 4.
It consists of Further, the centrifugal fan 1 is usually arranged in a fan casing 6 having a suction port 6a and a blowout port 6b. When the centrifugal fan 1 is driven to rotate, as shown by an arrow in FIG.
The air sucked from a flows into the inflow end 5a of the blade 5, then flows out from the outflow end 5b and is blown out from the air outlet 6b.

[0003]

However, in the conventional centrifugal fan 1 described above, the blade 5 has an inflow end 5a and an outflow end 5b.
The pressure increase over time decreases with increasing distance from the main plate 4. Therefore, when the pressure loss in the air blowing path becomes large, the airflow is separated from the position on the blade 5 where the pressure rise is small, and the airflow flows backward. Therefore, the vortexes 7 as shown in FIG. 18 are generated, and adverse effects such as a decrease in ventilation efficiency and an increase in ventilation noise occur.

Further, as a conventional heating cooker 8 using the above-mentioned conventional centrifugal fan 1, for example, Japanese Patent Application No. 2001
The thing as described in 3213291 etc. is mentioned. FIG. 19 shows the configuration of the heating cooker 8 described in Japanese Patent Application No. 2001-321291. In the conventional heating cooker 8, there is a problem that foreign matter such as dust and oil generated during cooking flows in through the suction port and is easily clogged in the air passage 9. As a result, the pressure loss in the ventilation path 9 is also likely to increase, so that the above-described conventional centrifugal fan 1 has adverse effects such as a reduction in ventilation efficiency and deterioration of ventilation noise.

The present invention has been made in view of the above problems, and an object thereof is to provide a centrifugal fan having a low noise and a high blowing efficiency by using a blade structure capable of suppressing the separation of the air flow. And to provide a heating cooker equipped with the centrifugal fan.

[0006]

A centrifugal fan and a heating cooker according to the present invention have the following configurations as means for solving the above problems.

The centrifugal fan of the present invention comprises a main plate which is provided perpendicular to a predetermined rotation axis and rotates around a predetermined rotation axis, and a plurality of sheets which are arranged in the vicinity of the outer peripheral portion of the main surface of the main plate. A vane, the vane including an inflow end facing the fluid inflow side and an outflow end facing the fluid outflow side, and the inflow end being formed by at least one of a concave portion and a convex portion A protruding portion is provided.

According to the above construction, since the growth and separation of the boundary layer on the suction surface of the blade is suppressed, a quiet and highly efficient centrifugal fan can be obtained.

The centrifugal fan of the present invention may have shrouds arranged on the blades. The centrifugal fan of the present invention may also be provided with protrusions at the ends of the blades other than the inflow end and the outflow end.

According to the above construction, the growth and separation of the boundary layer on the suction surface of the blade are supplementarily suppressed by the protrusions provided at the end portions of the blade except the inflow end and the outflow end.
Furthermore, a quiet and highly efficient centrifugal fan can be obtained.

The centrifugal fan of the present invention also has a protrusion
It may be arranged on all or part of the inflow end.

The centrifugal fan according to the present invention also has a protrusion
They may be arranged at equal pitch. According to the above configuration, since the growth and separation of the boundary layer on the suction surface of the blade are uniformly suppressed, the performance is slightly deteriorated due to the resistance due to the vertical vortex during the operation in the low static pressure region. However, during operation in the high static pressure region, a particularly quiet and highly efficient centrifugal fan can be obtained.

The centrifugal fan of the present invention also has a protrusion
They may be arranged at unequal pitches.

According to the above construction, only the growth and separation of the boundary layer on a part of the negative pressure surface of the blade is effectively suppressed. Therefore, if a predetermined unequal pitch is selected, a low static pressure region can be obtained. During operation, the resistance due to the vertical vortex is small and almost the same performance as the conventional one can be obtained, and at the time of operation in the high static pressure region, a quiet and highly efficient centrifugal fan can be obtained.

In the centrifugal fan of the present invention, when the width of the protruding portion is b and the height of the protruding portion is a, the value a / b obtained by dividing the height a of the protruding portion by the width b of the protruding portion is given. , (A / b) ≧ 0.
It is preferable to satisfy the conditions indicated by 05.

In the centrifugal fan of the present invention, more preferably, the height a of the protruding portion divided by the width b of the protruding portion is a /
b satisfies the condition of 0.60 ≧ (a / b) ≧ 0.11.

According to the above construction, the blades are installed rearward with respect to the radial direction perpendicular to the rotation direction, that is, the outer ends of the blades are located rearward of the inner ends of the blades in the rotation direction. In particular, the centrifugal fan has a particularly great effect of reducing noise and increasing efficiency.

In the centrifugal fan of the present invention, more preferably, the height a of the protruding portion divided by the width b of the protruding portion is a /
b satisfies the condition of 1.87 ≧ (a / b) ≧ 0.50.

According to the above construction, particularly large noise reduction and high efficiency effects can be obtained in the centrifugal fan in which the blades are installed in the radial direction substantially perpendicular to the rotation direction.

In the centrifugal fan of the present invention, more preferably, the height a of the protruding portion divided by the width b of the protruding portion is a /
b satisfies the condition represented by (a / b) ≧ 1.64.

According to the above construction, the blade is positioned forward in the rotational direction, that is, the outer end of the blade is located forward of the inner end of the blade in the rotational direction with reference to the radial direction perpendicular to the rotational direction. In the centrifugal fan installed as described above, particularly large noise reduction and high efficiency effects can be obtained.

In the centrifugal fan of the present invention, more preferably, the value a / b obtained by dividing the height a of the protrusion by the width b of the protrusion is the same for all the protrusions.

According to the above construction, a centrifugal fan having particularly excellent quietness and efficiency at a specific blade installation angle can be obtained.

The centrifugal fan of the present invention may also have a mixture of protrusions satisfying at least two of the above conditions.

According to the above configuration, in the centrifugal fan that operates by switching between normal rotation and reverse rotation, noise reduction and high efficiency can be obtained during both normal rotation operation and reverse rotation operation. .

In the centrifugal fan of the present invention, more preferably, the tip of the protrusion has a radius of curvature larger than 1 mm.

According to the above construction, the safety can be improved and the centrifugal fan can be handled more easily.

The heating cooker of the present invention is a heating cooker provided with a hot air flow passage arranged in communication with the heating chamber, and a centrifugal fan arranged in the hot air flow passage. Since the above-described centrifugal fan is used as the fan, quiet operation and high heating performance can be obtained.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIGS. 1 and 2 show a centrifugal fan 1 according to the present embodiment. The centrifugal fan 1 of this embodiment has a main shaft 4 to which a rotary shaft 3 of a drive motor 2 is vertically connected in a central portion thereof and which is rotationally driven by the drive motor 2 and an outer peripheral portion of the main plate 4 which is vertically arranged. It is equipped with a plurality of blades 5, 5 ,.

The centrifugal fan 1 has a suction port 6a.
A suction port 6a and blades 5, 5, ... Installed in the centrifugal fan 1 in a fan casing 6 having a blower outlet 6b
, And the inflow ends 5a, 5a, ... More specifically, the blades 5 are provided so as to extend in the radial direction of the circular main plate 4 which is vertical and circular with respect to the main surface of the main plate 4.

The blade 5 is the subject matter of the present invention, and has a flat plate-like basic form as shown in FIGS. 1 and 2, and is shown in FIG. As described above, the blade component 4b also made of an appropriate steel material is firmly fixed to the main plate component 4a made of an appropriate steel material by spot welding.

As shown in FIG. 4, in this blade 5, a triangular convex portion 10 is arranged at the inflow end 5a of the above-mentioned blade 5, and a protruding portion 12 composed of the convex portion 10 is formed. It is installed at equal pitch.

Further, as shown in FIG. 4, when the width of the above-mentioned protruding portion 12 is b and the drop between the convex portion 10 and the concave portion 11 is a, all the protruding portions 12 on the inflow end 5a are shown.
Are installed so that (a / b) = 1.

Therefore, when the centrifugal fan 1 is rotationally driven by the drive motor 2, the main flow of the air sucked from the suction port 6a is shown by the streamline A1 in FIGS. 1, 2 and 5. Thus, the air flows in from the inflow end 5a of the blade 5 and is blown out from the outflow end 5b to the air outlet 6b. When this air flow collides with the projecting portion 12, substantially uniform vertical vortices 13, 13, ... Are generated from the projecting portions 12, 12, ... As shown in FIG. The vertical vortex 1
, 13, gradually grow along the suction surface of the blade 5 toward the outflow end 5b side, but the adjacent vertical vortex 13
Since the pitch does not become larger than the pitch of the protruding portions 12 due to the mutual interference, a substantially uniform and strong vorticity is maintained near the outflow end 5b. The vorticity at a certain point can be defined as twice the angular velocity with respect to the central axis of that point.

In this case, energy is supplied to the entire boundary layer of air on the negative pressure surface of the blade 5 by the vertical vortex 13, and the growth of the boundary layer due to the increase of the pressure loss in the air flow passage is suppressed more effectively. As a result, the separation of air on the negative pressure surface is suppressed, the blowing noise of the centrifugal fan 1 is reduced, and the blowing efficiency is further improved.

As described above, due to the separation suppressing effect of the vertical vortex 13, the centrifugal fan 1 described above realizes efficient blowing performance with less blowing noise. Note that FIG. 6 shows a comparison of the blowing noise and static pressure of the centrifugal fan 1 with those of the centrifugal fan 1 having the conventional structure. Here, in each of the “air volume-blowing sound characteristic diagram” and the “air volume-static pressure characteristic diagram”, reference numerals L2 and L21 indicate characteristics of the centrifugal fan 1 according to the present embodiment, and reference numerals L1 and L11 indicate conventional structures. The characteristics of the centrifugal fan 1 are shown. From FIG. 6, in the centrifugal fan 1 of the present embodiment, as compared with the centrifugal fan 1 having the conventional structure, the vertical vortex 13 is generated in the low static pressure region where separation is unlikely to occur.
It can be seen that although the blowing noise is slightly increased and the flow rate is reduced due to its own resistance, the blowing noise is low and the flow rate is increased in the high static pressure region where separation is likely to occur.

Here, the protruding portion 1 of the inflow end 5a of the blade 5 is
2 is not limited to the one formed by only the convex portion 10 as shown in FIG. 4, but may be formed by at least one of the concave portion 11 and the convex portion 10. In addition, the shape of the above-mentioned protruding portion 12 is as shown in FIGS.
As shown in, the shape is not limited to a triangle and may be an arc shape, a rectangle, or a polygon, and the same effect can be obtained with any shape.
The above-mentioned protruding portion 12 of the inflow end 5a has only to be formed from at least one of the concave portion 11 and the convex portion 10, but if it is set in the range of (a / b) ≧ 0.05, a particularly large noise is generated. The effects of reduction and high efficiency were recognized.

Further, the protruding portion 12 of the inflow end 5a described above.
Is set in the range of 0.60 ≧ (a / b) ≧ 0.11, as shown in FIG. 13, the blades 5 are directed rearward with respect to the rotation direction, that is, the radial direction perpendicular to the rotation direction. In particular, when the outer end of the blade 5 is installed rearward of the inner end of the blade 5 with respect to, the effect of particularly large noise reduction and high efficiency is recognized.

Further, the protruding portion 12 of the inflow end 5a described above.
Is set to a range of 1.87 ≧ (a / b) ≧ 0.50, the blades 5 are installed in a radial direction substantially perpendicular to the rotation direction as shown in FIGS. 1 and 2. In particular, the effects of particularly large noise reduction and high efficiency were recognized.

Furthermore, the protruding portion 12 of the inflow end 5a described above.
Is set in the range of (a / b) ≧ 1.64, as shown in FIG. 14, the blade 5 is forward with respect to the rotational direction, that is, the radial direction perpendicular to the rotational direction is used as a reference. When the outer end of the blade is installed so as to be located in front of the inner end of the blade 5, particularly large noise reduction and high efficiency effects are recognized.

In addition, the effect of reducing the blast noise and improving the blast efficiency by the vertical vortex 13 described above depends on the shape, the installation position and the direction of at least one of the concave portion 11 and the convex portion 10 installed at the inflow end 5a. Depends only on
The material of the centrifugal fan 1 described above is not limited to steel, but may be resin or wood, and the same effect can be obtained as long as it is any material having a strength that does not cause damage during rotational driving. You can

Similarly, with respect to the method of forming the centrifugal fan 1, not only the method of fixing the main plate component 4a and the blade component 4b by spot welding, but the same effect can be obtained in the centrifugal fan 1 formed by an arbitrary forming method. Obtainable.

Further, as shown in FIG. 1, even if the above-mentioned centrifugal fan 1 is provided with the shroud 20 at the upper end, the same effect can be obtained.

Further, the drive motor 2 is not limited to the one having the above-mentioned structure, and the same effect can be obtained even if another rotary drive source is used.

A protruding portion 12 formed by at least one of the concave portion 11 and the convex portion 10 provided at the inflow end 5a of the blade 5 of the centrifugal fan 1.
May be arranged only in a part of the inflow end 5a, as shown in FIG. 7 (e). In this case, although the effect is slightly reduced, the design can be simplified, and it is relatively easy to secure the dimensional accuracy during mass production, which enables production at a lower cost.

Further, the concave portion 1 of the blade 5 of the centrifugal fan 1
1 and the protruding portion 12 are formed by at least one of the protrusions 10, the inflow end 5a and the outflow end 5b.
It may also be arranged at the end 14 of the blade 5 except for. In this case, as shown in FIG. 8, a slight vertical vortex is generated by the air flow passing through the end portions 14 of the blades 5 described above, and energy is slightly supplied to the vicinity of the region where the separation starts to occur. Can be supplementarily prevented.

Further, the concave portion 1 of the blade 5 of the centrifugal fan 1
It is more preferable that the protruding portion 12 formed by at least one of 1 and the convex portion 10 is rounded so that the radius of curvature is larger than 1 mm at the tip thereof. This is because even if a person accidentally touches the tip of the protruding portion 12, no damage is caused, so that safety can be improved and the centrifugal fan 1 can be handled more easily.

(Second Embodiment) FIG. 9 shows a blade 5 of a centrifugal fan 1 according to a second embodiment of the present invention. In the blade 5 of this embodiment, as shown in the figure, the protruding portions 12 formed by at least one of the concave portion 11 and the convex portion 10 are installed at unequal pitches, and the pitch of the protruding portions 12 is the inflow. At the end 5a, the distance from the position on the main plate 4 side to the main plate 4 becomes narrower exponentially. In other respects, the centrifugal fan 1 according to the present embodiment is common to the centrifugal fan 1 according to the first embodiment, and the same portions will be denoted by the same reference numerals and description thereof will be omitted.

When the centrifugal fan 1 of the second embodiment described above is rotationally driven by the drive motor 2, the main flow of air sucked from the suction port 6a flows in from the inflow end 5a of the blade 5 and its outflow end. It is blown out from the outlet 5b to the outlet 6b. When this air flow collides with the above-mentioned projecting portion 12, non-uniform vertical vortices 13, 13, ... Are generated from each projecting portion 12, 12, ... As shown in FIG. The vertical vortex 1
, 13, gradually grow along the suction surface of the blade 5 toward the outflow end 5b side, but the adjacent vertical vortex 13
Since the pitch of the protruding portions 12 does not become larger than the pitch of the protruding portions 12 due to mutual interference, the vertical vortices 13 near the main plate 4 having a large pitch of the protruding portions 12 gradually weaken near the outflow end 5b, and the pitch of the protruding portions 12 is narrow. The vertical vortex 13 near the position away from the main plate 4 grows strong and compact near the outflow end 5b.

In this case, the longitudinal vortex 13 concentrates energy on the boundary layer of the air near the position where the airflow is liable to separate from the main plate 4 on the negative pressure surface of the blade 5, and energy is supplied to the airflow path. By effectively suppressing the growth of the boundary layer with the increase of the pressure loss, the separation of air on the negative pressure surface is suppressed, the blowing noise of the centrifugal fan 1 is reduced, and the blowing efficiency is further improved. It will be further improved.

As described above, due to the effect of suppressing the separation by the vertical vortex 13, the centrifugal fan 1 realizes efficient blowing performance with less blowing noise. Note that FIG. 11 shows a comparison of the blowing noise and static pressure of the centrifugal fan 1 with those of the centrifugal fan 1 having the conventional structure. Here, in each of the "flow rate-blowing noise characteristic diagram" and the "flow rate-static pressure characteristic diagram", reference numerals L3 and L31 indicate characteristics of the centrifugal fan 1 according to the present embodiment, and reference numerals L1 and L11 indicate conventional structures. The characteristics of the centrifugal fan 1 are shown. It can be seen from FIG. 11 that the centrifugal fan 1 of the present embodiment has the following characteristics as compared with the centrifugal fan 1 having the conventional structure. That is, since the resistance of the vertical vortex 13 itself is not large in the low static pressure region where separation is unlikely to occur, the blowing noise and the flow rate are almost the same, and the blowing noise is low and the flow amount increases in the high static pressure region where separation is likely to occur. . However, in the high static pressure region, especially in the so-called closed cut-off pressure region where the flow rate is near 0, since the effect of the vertical vortex is small at the position close to the main plate, separation begins to occur, so the improvement effect on the blowing noise and the flow rate is weakened. .

Here, the pitch of the projecting portions 12 of the blades 5 may be not only exponential but also an arithmetic series or a quadratic function, and the pitch is wide near the position where airflow separation is unlikely to occur, It suffices if the pitch is narrow near the position where peeling easily occurs.

If it is desired to particularly suppress the separation of the airflow at a certain position on the inflow end 5a regardless of the likelihood of the separation of the airflow, the protruding portion 12 at that position is used.
This requirement can be met by arranging the protruding portions 12 formed by at least one of the concave portions 11 and the convex portions 10 at an arbitrary unequal pitch such that the pitch becomes narrower.

(Embodiment 3) FIG. 12 shows blades 5 of a centrifugal fan 1 according to Embodiment 3 of the present invention.
In the blade 5 of this embodiment, when the width of the protruding portion 12 formed by at least one of the concave portion 11 and the convex portion 10 is b and the head between the convex portion 10 and the concave portion 11 is a. , As shown, (a / b) = 0.3
The blunt projecting portions 12a of 4 and the sharp projecting portions 12b of (a / b) = 1.95 are alternately arranged.

Further, the installation angle of the blades 5 of the centrifugal fan 1 of the present embodiment is inclined from the radial direction to the negative rotation direction by 40 ° with the direction indicated by the arrow B in FIG. 13 as the positive rotation direction,
That is, the outer end of the blade 5 is installed so as to rotate later than the inner end of the blade 5. Further, a reversible rotation driving motor 2a capable of forward and reverse rotation driving is connected to the central portion of the centrifugal fan 1 described above. In other respects, the centrifugal fan 1 according to the present embodiment is common to the centrifugal fan 1 according to the first embodiment, and the same portions will be denoted by the same reference numerals and description thereof will be omitted.

When the centrifugal fan 1 of the above-described third embodiment is rotationally driven in the positive direction by the reversible rotary drive motor 2a, the blades 5 have a radial direction with the direction indicated by the arrow B in FIG. 14 as the positive rotational direction. The vertical vortices 13 generated from the blunt projecting portion 12a of (a / b) = 0.34 are installed at an angle of 40 ° in the negative rotation direction. By supplying more energy to the boundary layer, the growth of the boundary layer is suppressed more effectively.

Further, the reversible rotation drive motor 2a is used to drive the motor shown in FIG.
When the blade 5 is rotationally driven in the direction opposite to the direction indicated by the arrow B, the outer end of the blade 5 is installed so as to advance and rotate with respect to the inner end of the blade 5. /
b) = 1.95 The vertical vortex 13 generated from the sharp protruding portion 12b supplies more energy to the boundary layer of air on the suction surface of the blade 5, thereby suppressing the growth of the boundary layer more effectively. To be done.

Therefore, in the centrifugal fan 1 of the present embodiment, it is possible to obtain a large noise reduction effect and a high efficiency effect both when it is rotationally driven in the forward direction and when it is rotationally driven in the reverse direction.

Here, the value of (a / b) is not limited to the above value, and the same effect can be obtained as long as it is a value suitable for the installation angle of the blade 5.

Further, with respect to the arrangement of the protruding portions 12, not only the arrangement of the protruding portions 12 is alternately arranged, but the same effect can be obtained even in other arrangements.

(Embodiment 4) FIG. 15 shows blades 5 of a centrifugal fan 1 according to Embodiment 4 of the present invention.
The blade 5 of this embodiment is installed so that the protruding portions 12 formed by at least one of the concave portion 11 and the convex portion 10 have unequal pitches and different values of (a / b) as shown in the figure. And the protruding portion 1
The pitch of 2 is from the main plate 4 side to the main plate 4 at the inflow end 5a.
Becomes exponentially narrower as
Regarding the value of b), at the inflow end 5a, the distance increases from the position on the main plate 4 side to the main plate 4 in the arithmetic series.

The value of (a / b) of the projecting portion 12 existing farthest from the main plate 4 is 1.95, and the blade 5 is positive in the direction indicated by arrow B in FIG. The blades 5 are arranged such that the blades 5 incline from the radial direction by 40 ° in the negative rotation direction, that is, the outer ends of the blades 5 are behind the inner ends of the blades 5 with respect to the positive rotation direction.
In other respects, the centrifugal fan 1 according to the present embodiment is common to the centrifugal fan 1 according to the second embodiment, and the same portions will be denoted by the same reference numerals and description thereof will be omitted.

The centrifugal fan 1 according to the above-described fourth embodiment has the same principle as that of the centrifugal fan 1 according to the above-described embodiment, whereby air separation on the negative pressure surface of the blade 5 is suppressed, and the centrifugal fan 1 described above is The blast noise is reduced and the blast efficiency is improved.

However, in the blade 5 of the centrifugal fan 1 of the present embodiment, the value of (a / b) of the protruding portion 12 at the position separated from the main plate 4 as described above is relative to the installation angle of the blade 5. The value is given so that the optimum vertical vortex 13 is generated.

Further, in the blade 5 of the centrifugal fan 1 of this embodiment, (a of the protruding portion 12 near the main plate 4 is
The value of / b) is given such a value that the vertical vortex 13 having energy enough to affect the flow with respect to the installation angle of the blade 5 is unlikely to be generated.

Therefore, in the blade 5 of the centrifugal fan 1 of the present embodiment, the vertical vortex 1 grows stronger and more compactly than in the second embodiment in the vicinity of the position away from the main plate 4, whereas The vertical vortices 13 near the main plate become weaker than in the case of the second embodiment and gradually decline. Therefore, the characteristics of the centrifugal fan 1 of the present embodiment are more suitable than the characteristics of the centrifugal fan 1 of the second embodiment described above.

Here, the degree of change in the value of (a / b) of the protruding portion 12 at the inflow end 5a of the blade 5 is as follows.
Besides exponential series, it may be exponential or quadratic. That is, the degree of change in the (a / b) value of the protruding portion 12 is such that the (a / b) value of the protruding portion 12 near the position where airflow separation is unlikely to occur is a suitable value for the blade installation angle. If the value of (a / b) described above is a value suitable for the installation angle of the blade 5 near the position where airflow separation easily occurs, a protrusion having an arbitrary different value of (a / b) The parts 12 may be arranged in a mixed manner.

When it is desired to particularly suppress the separation of the air flow at a certain position regardless of the likelihood of the separation of the air flow, the value of (a / b) at that position is the installation angle of the blade 5. This requirement can be satisfied by arranging the projecting portion 12 with an arbitrary (a / b) value change so as to have a suitable value for the above.

(First Embodiment of Heating Cooker) Next, an embodiment of the heating cooker 8 according to the present invention will be described.
FIG. 16 shows an air blower 15 in the main body of the heating cooker 8.
It is a block diagram which shows. The heating cooker 8 is configured such that the air blower 15 including the centrifugal fan 1, the drive motor 2, and the air blow path 9 of the first embodiment communicates with the inside of the heating chamber 16.

Since the heating cooker 8 of the present embodiment is provided with the centrifugal fan 1 of the first embodiment, as described above, the characteristic of the centrifugal fan 1, that is, the blowing noise is low and the blowing effect is high. On the basis of the characteristic that the above is obtained, the heating cooker 8 having both quiet running performance and high heating performance can be obtained.

Even if the centrifugal fan 1 described in the first to fourth embodiments is applied as the centrifugal fan 1, the same effect can be obtained.

(Second Embodiment of Heating Cooker) Next, a heating cooker 8 according to a second embodiment of the present invention will be described. FIG. 17: is a block diagram which shows the air blower 15 in the main body of the heating cooker 8. As shown in FIG. This heating cooker 8 has a centrifugal fan 1 according to the third embodiment, a reversible rotation drive motor 2a capable of forward and reverse rotation drive, and a flow path downstream of the outlet 6b of the centrifugal fan 1 described above. An air blowing device 15 including the air blowing path 9 is configured to communicate with the inside of the heating chamber 16.

Since the heating cooker 8 according to the present embodiment is provided with the centrifugal fan 1 according to the third embodiment, it is possible to perform the above-described operation regardless of whether the centrifugal fan 1 is rotating normally or reversely. As described above, based on the characteristics of the centrifugal fan 1, that is, the characteristics that the blowing noise is low and a high blowing effect is obtained, the heating cooker 8 having both quiet running performance and high heating performance can be obtained.

It should be understood that the embodiments disclosed this time are illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description but by the scope of the claims, and is intended to include meanings equivalent to the scope of the claims and all modifications within the scope.

[0076]

According to the centrifugal fan of the present invention and the heating cooker equipped with the centrifugal fan, by having the blade structure capable of suppressing the separation of the air flow, low noise and high blowing efficiency are achieved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a centrifugal fan according to a first embodiment of the present invention.

FIG. 2 is a perspective view of the centrifugal fan.

FIG. 3 is an enlarged perspective view showing a molding method of the centrifugal fan.

FIG. 4 is an enlarged plan view of blades of the centrifugal fan.

FIG. 5 is an enlarged perspective view of blades of the centrifugal fan.

FIG. 6 is a characteristic diagram of “pressure-flow rate” and “blower noise-flow rate” of the centrifugal fan.

FIG. 7 is an enlarged plan view showing blades of a centrifugal fan according to another embodiment that is similar to the first embodiment.

FIG. 8 is an enlarged perspective view showing blades of a centrifugal fan according to still another embodiment, which is similar to the first embodiment.

FIG. 9 is an enlarged plan view showing blades of a centrifugal fan according to Embodiment 2 of the present invention.

FIG. 10 is an enlarged perspective view of blades of the centrifugal fan.

FIG. 11 is a characteristic diagram of “pressure-flow rate” and “blower noise-flow rate” of the centrifugal fan.

FIG. 12 is an enlarged plan view showing blades of a centrifugal fan according to Embodiment 3 of the present invention.

FIG. 13 is a plan view of a centrifugal fan according to a third embodiment of the present invention.

FIG. 14 is a plan view of a centrifugal fan related to the embodiment of the invention.

FIG. 15 is an enlarged plan view showing blades of a centrifugal fan according to Embodiment 4 of the present invention.

FIG. 16 is a cross-sectional view of the heating cooker according to the first embodiment of the heating cooker of the present invention.

FIG. 17 is a perspective view of a heating cooker according to a second embodiment of the heating cooker of the present invention.

FIG. 18 is a sectional view showing a configuration of a conventional centrifugal fan.

FIG. 19 is a cross-sectional view showing a configuration of a conventional heating cooker.

[Explanation of symbols]

1 Centrifugal Fan, 2 Drive Motor, 2a Reversible Rotation Drive Motor, 3 Rotation Shaft, 4 Main Plate, 4a Main Plate Parts, 4b
Blade parts, 5 blades, 5a inflow end, 5b outflow end, 6
Fan casing, 6a inlet, 6b outlet, 7
Vortex, 8 Heating cooker, 9 Air flow path, 10 Convex part, 1
1 concave part, 12 protruding part, 12a dull protruding part, 12
b sharp protruding part, 13 vertical vortex, 14 end part, 15 blower, 16 heating chamber, 20 shroud, A1 streamline, B rotation direction, L1 pressure-flow curve of a conventional centrifugal fan, L2 Embodiment of the present invention Centrifugal fan pressure-flow rate curve according to Embodiment 1, L3 Centrifugal fan pressure-flow rate curve according to Embodiment 2 of the present invention, L11 Blower noise-flow rate curve of a conventional centrifugal fan, L21 First embodiment of the present invention Noise-flow rate curve of centrifugal fan related to L31
Blower noise of the centrifugal fan according to the second embodiment of the present invention-
Flow curve.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3H033 AA02 AA13 BB02 BB06 CC01                       DD03 EE06 EE08 EE19                 3H035 DD04 DD05                 3L086 AA03 DA30

Claims (14)

[Claims] 1. A main plate which is provided perpendicular to a predetermined rotation axis and rotates around the predetermined rotation axis, and a plurality of blades arranged near the outer peripheral portion of the main surface of the main plate. The vane includes an inflow end facing the inflow side of the fluid and an outflow end facing the outflow side of the fluid, and is formed by at least one of a concave portion and a convex portion at the inflow end. Centrifugal fan with a protruding part. 2. The centrifugal fan according to claim 1, wherein a shroud is arranged on the blade. 3. The centrifugal fan according to claim 1, wherein the protruding portion is provided also at the end portions of the blades excluding the inflow end and the outflow end. 4. The centrifugal fan according to claim 1, wherein the protrusion is arranged on all or part of the inflow end. 5. The protrusions are arranged at an equal pitch,
The centrifugal fan according to claim 1. 6. The centrifugal fan according to claim 1, wherein the protrusions are arranged at unequal pitches. 7. When the width of the protrusion is b and the height of the protrusion is a, a value a / b obtained by dividing the height a of the protrusion by the width b of the protrusion is: The centrifugal fan according to any one of claims 1 to 6, which satisfies the condition a / b) ≧ 0.05. 8. The height a of the protrusion is equal to the width b of the protrusion.
The value a / b divided by 0.60 ≧ (a / b) ≧ 0.11
The centrifugal fan according to claim 7, wherein the centrifugal fan has the following conditions. 9. The value a / b obtained by dividing the height a of the protrusion by the width b of the protrusion satisfies the condition of 1.87 ≧ (a / b) ≧ 0.50. 7. The centrifugal fan according to 7. 10. The value a / b obtained by dividing the height a of the protrusion by the width b of the protrusion satisfies the condition represented by (a / b) ≧ 1.64. Centrifugal fan. 11. The centrifuge according to claim 7, wherein a value a / b obtained by dividing a height a of the protrusion by a width b of the protrusion is the same for all the protrusions. fan. 12. The centrifugal fan according to claim 7, wherein the protrusions are mixed so as to satisfy at least two of the conditions according to any one of claims 8 to 10. 13. The radius of curvature of the tip of the protrusion is 1 m.
The centrifugal fan according to any one of claims 1 to 12, which is larger than m. 14. A heating cooker comprising a hot air flow passage arranged in communication with a heating chamber and a centrifugal fan arranged in the hot air flow passage, wherein the centrifugal fan is:
A heating cooker using the centrifugal fan according to any one of claims 1 to 13.