JP2020060162A - Blower - Google Patents

Abstract

To provide a blower capable of suppressing degradation of blowing performance by recirculation airflow flowing into a spiral ventilation flue.SOLUTION: A blower 1 is provided with a spiral ventilation flue 36 formed along a radial outer side of an impeller 10, and a blowout ventilation flue 37 toward a blowout port 35 from a terminal end portion of the spiral ventilation flue 36, inside of a casing 30 housing the impeller 10 rotated on a rotating shaft 21 as a center inside. A connection portion 33e for separating an inflow position into which recirculation airflow a2 flows and a starting end position of the spiral ventilation flue 36 as a minimum clearance of the spiral ventilation flue 36, is disposed between an impeller-side end portion of a tongue portion 33d partitioning the spiral ventilation flue 36 and the blowout ventilation flue 37, and a winding start point P1 of a spiral portion 33a.SELECTED DRAWING: Figure 3

Description

  The present invention relates to, for example, a blower used in a vehicle air conditioner.

  BACKGROUND ART Conventionally, as this type of blower, there is known one provided with a tubular impeller and a casing in which a spiral ventilation passage is formed on the radially outer side of an impeller housed inside.

  The casing was provided on a first side plate provided on one end side in the axial direction of the impeller, a second side plate provided on the other end side in the axial direction and having an air intake port, and provided on the outer side in the radial direction of the impeller. The outer peripheral plate is provided, and the space between the first side plate and the second side plate and between the outer peripheral portion of the impeller and the outer peripheral plate serves as a spiral ventilation passage. The spiral ventilation passage is formed such that the cross-sectional area of the flow passage gradually increases from the winding start point at the winding start position to the winding end point at the winding end position.

  Further, a tongue portion serving as a starting point of the spiral shape of the spiral ventilation passage is formed on the upstream side of the spiral ventilation passage and at the position closest to the outer peripheral portion of the impeller on the outer peripheral plate.

  By the way, in the vicinity of the tongue part of the blower, the internal pressure difference is the largest and the airflow is turbulent easily, so in addition to the airflow blown from the outlet through the swirl ventilation passage (blowing airflow) An airflow (recirculation airflow) that re-enters the start end position of the spiral ventilation passage is generated.

  Since this recirculation air flow causes deterioration of the blowing performance of the blower and noise, for example, like the blower disclosed in Patent Document 1 below, an auxiliary tongue is provided on the main tongue portion of the tip of the side plate that forms the discharge flow path. Measures have been taken to reduce noise while suppressing the deterioration of the ventilation performance.

JP-A-6-2699

  The blower disclosed in Patent Document 1 has a configuration in which an auxiliary tongue is projected on the main tongue for the purpose of improving blowing performance and reducing noise. However, when the air toward the outlet collides with the auxiliary tongue, There is a problem that turbulence of the air flow occurs near the outlet side of the auxiliary tongue and new noise is generated. Further, since the auxiliary tongue portion is provided so as to project on the discharge flow path, the auxiliary tongue portion may act as a barrier and adversely affect the air volume.

  As described above, in the blower of Patent Document 1, the effect of reducing the noise due to the recirculation airflow by projecting the plate-shaped auxiliary tongue portion on the main tongue portion is provided. Such new problems will arise.

  The present invention has been made in view of the various problems in the conventional techniques described above, and an object of the present invention is to prevent the adverse effect on the blowing performance by the recirculation airflow flowing near the start end of the spiral ventilation passage. It is to provide a blower that can be prevented.

  A first aspect of the present invention is directed to an impeller that rotates about a rotation axis to allow air to flow in from an axial end portion and to flow out from an outer peripheral portion, and to extend radially outward of the impeller housed inside. A casing having a spiral portion in which a swirl air passage is formed, and a blowout air passage extending from the swirl portion and extending from the end portion of the swirl air passage to the outlet is formed; and a start end position of the swirl air passage. And a tongue portion that separates the blowout air passage from each other, and divides the first airflow flowing from the blowout air passage to the blowout port toward a start end position of the spiral ventilation passage near the tongue portion. A connecting portion that separates the inflow position of the second airflow into the spiral ventilation passage from the start end position of the spiral ventilation passage is provided between the impeller-side end of the tongue portion and the winding start point of the spiral portion. It is a blower characterized by being blown.

  A second aspect of the present invention is the blower according to the first aspect of the present invention, in which a distance B from the impeller-side end of the tongue toward the radial direction of the impeller to the outer periphery of the impeller is B. Is a fan having a distance of A or more from a winding start point of the spiral portion extending in a radial direction of the impeller to an outer peripheral portion of the impeller.

  A third aspect of the present invention is the blower according to the second aspect of the present invention, wherein the ratio of the lengths of the interval B and the interval A is 1.1 ≦ B / A ≦ 1.4. It is a blower characterized by that.

  A fourth aspect of the present invention is the blower according to any one of the first to third aspects of the present invention, wherein an imaginary line L1 connecting the rotation center of the impeller and the winding start point, and the impeller. The blower is characterized in that the connecting portion is provided within an angle α of 5 ° ≦ α ≦ 20 ° formed by an imaginary line L2 connecting the center of rotation of the tongue portion and the end of the tongue portion on the impeller side. is there.

  According to the present invention, the connection portion is provided between the impeller side end portion of the tongue portion and the winding start point of the spiral portion, so that the inflow position of the recirculated airflow into the spiral ventilation passage and the start end position of the spiral ventilation passage. Since the recirculation airflow can be separated and the velocity gradient when the recirculation airflow flows into the swirl ventilation passage can be made gentler than that of the conventional device, the blowing performance can be improved.

It is the whole blower perspective view showing one embodiment of the present invention. It is the top view seen from the suction inlet side of a blower. (A) is a plane sectional view of a blower. (B) is a partial enlarged sectional view of the vicinity of the tongue. FIG. 3 is a sectional view taken along line AA of FIG. 2. (A)-(c) is a figure which shows the example of a form of a connection part. It is a figure which shows the example of specifications of the air blower in an Example. It is a graph which compared the fan efficiency in Example 1-Example 8 with the fan efficiency of a conventional product.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings. The present invention is not limited to this embodiment, and all other forms, examples, and operational techniques that can be implemented by those skilled in the art based on this form are all included in the scope of the present invention. To do.

  In the following description with reference to the accompanying drawings in this specification, when the terms up, down, left, and right are used to indicate directions and positions, this is as illustrated by the user. If you look at the top, bottom, left, right matches. In addition, in the drawings attached to this specification, for convenience of illustration and understanding, the scale, vertical-horizontal dimension ratio, shape, and the like may be changed from the actual one and may be schematically expressed. It is an example and does not limit the interpretation of the present invention.

First, the configuration of the blower of the present invention will be described with reference to FIGS.
The blower 1 of the present invention is a centrifugal blower, and is used as, for example, a blower unit of a vehicle air conditioner.

  As shown in FIG. 1, the blower 1 includes an impeller 10 formed in a cylindrical shape, an electric motor 20 for rotating the impeller 10, and a casing 30 in which the impeller 10 is housed. There is.

  As shown in FIG. 3 or 4, the impeller 10 includes a plurality of blades 11, a base plate 12 provided on one end side in the axial direction, and a rim 13 for connecting the blades 11 provided on the other end side in the axial direction. And have.

  The plurality of blades 11 are arranged so as to extend circumferentially around the rotation shaft 21 of the electric motor 20 from the inner side to the outer side in the radial direction. Each blade 11 has, for example, an elongated plate shape in which the outer side in the radial direction of the impeller 10 is curved toward one side in the circumferential direction with respect to the inner side in the radial direction, and is spaced at regular intervals along the outer peripheral edge of the substrate 12. Is provided. One end of each blade 11 is fixed on the surface of the substrate 12, and the other end is connected to the rim 13.

  The substrate 12 is a disc-shaped member that is connected to one end of the plurality of blades 11 on the outer peripheral side, is fixed to the rotary shaft 21 of the electric motor 20, and is configured to be rotatable around the rotary shaft 21. .

  The substrate 12 has an overhanging portion 12a that gradually extends from the radially inner side of the outer peripheral edge to which one end of each blade 11 is connected to the central portion toward the other axial end. A concave portion is formed on one end face in the axial direction of the overhanging portion 12a, the concave portion being gradually recessed toward the radial center with respect to the outer peripheral side.

  The rim 13 is a cylindrical member in which the other ends of the blades 11 are connected to each other at intervals in the circumferential direction. By connecting the plurality of blades 11 to the rim 13, the standing state of each blade 11 is maintained.

  As shown by the arrow in FIG. 3, when the impeller 10 is rotated in one of the circumferential directions (the curved direction of the blades 11) about the center in the radial direction, the impeller 10 is an axial end portion via the suction port 34. Air flows inward from the other end in the direction, and radially flows out radially from the gap between the blades 11 toward the outside.

  As shown in FIG. 4, the electric motor 20 is arranged in a concave portion of one end face of the substrate 12 in the axial direction on the one end side in the axial direction of the impeller 10. The rotating shaft 21 of the electric motor 20 is connected to the radial center of the substrate 12, and rotates the impeller 10 toward one side in the circumferential direction, which is the direction in which the blades 11 are curved.

  As shown in any of FIGS. 1, 2, and 4, the casing 30 is provided on the first side plate 31 provided on one axial side of the impeller 10 and on the other axial side of the impeller 10. It has a second side plate 32, and an outer peripheral plate 33 connected between the outer peripheral portions of the first side plate 31 and the second side plate 32 and extending along the circumferential direction of the impeller 10.

  Further, as shown in FIG. 3, in the casing 30, a spiral air passage 36 for circulating the air flowing in from the suction port 34 in the rotation direction of the impeller 10 from the outer peripheral portion of the impeller 10, and a spiral air passage 36. A blow-out air passage 37 is provided which connects the end portion of 36 and the blow-out port 35.

  A motor support hole 31a for supporting the electric motor 20 in a penetrating state is provided in a substantially central portion of the first side plate 31.

  A suction port 34 for sucking air into the casing 30 is provided at a substantially central portion of the second side plate 32. In addition, a cover portion 32a that surrounds the other end in the axial direction of the rim 13 of the impeller 10, the radially inner surface side, and the outer surface side is provided at the edge of the suction port 34 of the second side plate 32.

  As shown in FIG. 3, the outer peripheral plate 33 includes a spiral spiral portion 33a in which the distance from the rotation axis of the impeller 10 gradually increases along the rotation direction of the impeller 10, and a radial outer side of the spiral portion 33a. Of the straight line portion 33b extending linearly from the end of the tongue portion 33d, the extending portion 33c extending linearly from the outlet side end of the tongue portion 33d, the winding start point P1 of the spiral portion 33a, and the extending portion 33c. The tongue portion 33d is provided between the tongue portion 33d and the base end portion, and the connecting portion 33e is connected between the winding start point P1 of the spiral portion 33a and the impeller side end portion of the tongue portion 33d.

  The spiral portion 33a is formed in a spiral shape from a winding start point P1 that is a predetermined distance from the outer peripheral portion of the impeller 10 as a winding start position, and from there to a winding end point P2 that is a winding end position. The interval between the inner peripheral surface of the spiral portion 33a and the outer peripheral portion of the impeller 10 is formed so as to gradually increase from the winding start point P1 toward the winding end point P2.

  The linear portion 33b extends linearly from the winding end point P2 of the spiral portion 33a along the air blowing direction.

  The extending portion 33c continuously extends from the air outlet side end of the tongue portion 33d at a distance from the linear portion 33b.

  An air outlet 35 for blowing out the air sucked into the casing 30 through the air inlet 34 is provided at the extension side end portions of the straight portion 33b and the extension portion 33c. The air outlet 35 is formed at an end portion surrounded by the first side plate 31, the second side plate 32, the linear portion 33b, and the extending portion 33c.

  As shown in FIG. 5, the tongue portion 33d is an arc-shaped member that curves in a direction opposite to the spiral portion 33a with a predetermined radius of curvature. One end of the tongue portion 33d (end portion on the impeller side) is connected to one end portion of the connecting portion 33e, and the other end (end portion on the blowing side) is connected to the base end portion of the extending portion 33c.

  The connecting portion 33e is a member that is connected between the spiral portion 33a and the tongue portion 33d, and has one end connected to the impeller side end portion of the tongue portion 33d and the other end connected to the winding start point P1 of the spiral portion 33a. To be done.

  As described in the section of the background art, in the vicinity of the tongue portion 33d of the blower 1, the internal pressure difference is the largest and the airflow is likely to be disturbed. Therefore, the air sent out from the suction port 34 through the impeller is re-flowed to the upstream side of the swirling air passage 36 and the blowing air flow a1 which is the first airflow toward the air outlet 35 with the tongue portion 33d as a boundary. It is divided into the recirculating airflow a2 that is the second inflowing airflow.

  Therefore, in the present invention, in order to suppress the deterioration of the blowing performance due to the recirculation airflow a2, the connection portion 33e is provided between the winding start point P1 of the spiral portion 33a and the impeller side end of the tongue portion 33d, and the recirculation airflow is provided. The inflow position where a2 flows into the spiral ventilation passage 36 is moved to the upstream side of the start end position of the spiral ventilation passage 36, and the velocity gradient of the recirculation airflow a2 is made gentle before flowing into the spiral ventilation passage 36.

As shown in FIG. 5, the shape of the connecting portion 33e includes three forms.
<Form Example 1>
As shown in FIG. 5A, in the first embodiment, a flat plate is used as the connecting portion 33e, and the winding start point P1 of the spiral portion 33a and the impeller side end portion of the tongue portion 33d are linearly connected. It is a composition.
<Form Example 2>
As shown in FIG. 5B, in the second embodiment, the connecting portion 33e is a convex member curved to have a predetermined curvature so as to bulge toward the impeller 10 side, and the winding start point P1 of the spiral portion 33a and the tongue portion 33d. It is the structure which connected with the impeller side end part.
<Form Example 3>
As shown in FIG. 5C, in the third exemplary embodiment, the connecting portion 33e is a concave member curved to a predetermined curvature in a direction away from the impeller 10, and the winding start point P1 of the spiral portion 33a and the blade of the tongue portion 33d. This is a configuration in which the vehicle side end is connected.

  Further, when the connecting portion 33e is provided, the distance from the winding start point P1 to the outer peripheral portion of the impeller 10 in the radial direction of the impeller 10 is defined as "interval A", and the tongue portion is directed in the radial direction of the impeller 10. When the distance from the end of the impeller on the side of the impeller 33d to the outer peripheral portion of the impeller 10 is “interval B”, the interval B is set to be a distance equal to or greater than the interval A (A ≦ B).

  For example, when the connecting portion 33e is the flat plate of Embodiment 1 and the distance A is smaller than the distance B, the connecting portion 33e is provided so as to gradually incline from the winding start point P1 of the spiral ventilation passage 36 toward the air outlet 35, The distance between the outer peripheral portion of the impeller 10 and the connecting portion 33e from the distance A to the distance B gradually increases.

  The distance A and the distance B are preferably adjusted in the range of the ratio of lengths of 1.0 ≦ B / A ≦ 1.5, more preferably 1.1 ≦ B / A ≦ 1.4. And more preferably 1.2 ≦ B / A ≦ 1.3.

  Further, the region in which the connecting portion 33e is provided connects the virtual line L1 connecting the rotation center O of the impeller 10 and the winding start point P1, and the rotation center O of the impeller 10 and the impeller side end of the tongue 33d. The angle α formed by the imaginary line L2 is preferably in the range of 5 ° ≦ α ≦ 20 °. This angle α is defined in the above range based on the angle θ of the dominant angle of the angle formed by the imaginary line L1 and the imaginary line L3 connecting the winding end point P2 of the spiral portion 33a from the rotation center O of the impeller 10. To be done.

  As described above, by providing the connecting portion 33e between the swirl portion 33a and the tongue portion 33d based on the above conditions, the recirculation airflow a2 split from the blowout airflow a1 is temporarily provided before flowing into the spiral airflow passage 36. It hits the connecting portion 33e, and flows from there to the starting end position of the spiral ventilation passage 36 along the connecting portion 33e. That is, the connecting portion 33e separates the position (inflow position) where the recirculation airflow a2 flows in from the starting end position (position of the winding start point P1 of the spiral portion 33a) which is the minimum gap of the spiral air passage 36. Therefore, the pressure in the vicinity of the tongue portion 33d decreases, the velocity gradient of the recirculation air flow a2 becomes gentle, and the air blowing function can be improved.

  The spiral air passage 36 is provided between the first side plate 31 and the second side plate 32 and between the outer peripheral portion of the impeller 10 and the spiral portion 33 a of the outer peripheral plate 33. As shown in FIG. 3, in the spiral ventilation passage 36, the width dimension of the ventilation passage gradually increases in the radial direction from the start end position to the end position, so that the flow passage area of air gradually increases.

  The blowout air passage 37 is provided between the first side plate 31 and the second side plate 32 and between the linear portion 33b and the extending portion 33c. As shown in FIG. 3, the blowout air passage 37 is a ventilation passage that extends substantially linearly from the end side of the spiral airflow passage 36, and the airflow is provided in the radial direction from the end portion of the spiral airflow passage 36 toward the air outlet 35. The width of the road gradually increases.

  In the blower 1 having the above-described configuration, when the electric motor 20 is driven to rotate the impeller 10 in one circumferential direction, the air outside the casing 30 passes through the suction port 34 provided in the second side plate 32 and the inside of the casing 30. Inhaled into. The air sucked into the casing 30 through the suction port 34 flows inward from the other axial end of the impeller 10 and radially flows out from the outer peripheral portion of the impeller 10.

  The air that radially flows out from the outer peripheral portion of the impeller 10 flows through the spiral ventilation passage 36 and the outlet ventilation passage 37 of the casing 30 and is blown out from the outlet 35 as an outlet airflow a1. The recirculation airflow a2 flows toward the start end position of the spiral ventilation passage 36.

  By providing the connecting portion 33e between the spiral portion 33a and the tongue portion 33d, the inflow position into the spiral air passage 36 and the start end position of the spiral air passage 36 are separated. Therefore, the recirculation airflow a2 first strikes the connecting portion 33e before flowing into the starting end position of the spiral ventilation passage 36. When the recirculation airflow a2 hits the connecting portion 33e, the high pressure state at the starting end position of the spiral ventilation passage 36 is relaxed.

  Further, the recirculation airflow a2 that hits the connecting portion 33e is guided to the starting end position of the spiral ventilation passage 36 along the connecting portion 33e. The connection portion 33e separates the inflow position of the recirculation airflow a2 into the spiral airflow passage 36 and the start end position of the spiral airflow passage 36, so that the velocity gradient of the recirculation airflow a2 becomes gentle and aerodynamic noise is generated. Is suppressed.

  As described above, in the above-described blower 1, the inflow position where the recirculation airflow a2 flows between the winding start point P1 of the spiral portion 33a and the end of the tongue portion 33d on the impeller side, and the minimum of the spiral ventilation passage 36. A connecting portion 33e is provided to separate the start end position of the spiral ventilation passage 36, which is a gap.

  As a result, the inflow position of the recirculation airflow a2 into the spiral airflow passage 36 and the start end position of the spiral airflow passage 36 are separated, so that the pressure near the tongue portion 33d decreases and the velocity gradient of the recirculation airflow a2 decreases. It becomes gentle, and the air blowing performance can be improved.

  Further, the distance B from the end of the tongue portion 33d facing the radial direction of the impeller 10 to the outer peripheral part of the impeller 10 is determined by the impeller 10 starting from the winding start point P1 of the spiral part 33a extending in the radial direction of the impeller 10. The distance A to the outer peripheral portion of 10 is equal to or larger than A. As a result, the pressure in the vicinity of the tongue portion 33d is further reduced, and the air blowing performance can be improved.

  Furthermore, by setting the value of the ratio of the lengths of the interval B and the interval A to 1.1 ≦ B / A ≦ 1.4, the interval B becomes wider than the interval A, so that the air blowing performance is further improved. You can

  Further, an angle α formed by an imaginary line L1 connecting the rotation center O of the impeller 10 and the winding start point P1 and an imaginary line L2 connecting the rotation center O of the impeller 10 and the end of the tongue portion 33d on the impeller side. By providing the connecting portion 33e in the range of 5 ° ≦ α ≦ 20 °, the inflow position of the recirculation airflow a2 into the spiral air passage 36 and the start end position of the spiral air passage 36 are reliably separated, and the air blowing performance is improved. It is possible to exert the effect of causing.

  Next, performance evaluation by the blower 1 according to the present invention will be described with reference to specific examples.

[Blower specifications]
FIG. 6 shows the specifications of the blower 1 used in the examples. The connecting portion 33e used was the flat plate shown in FIG. 5 (a).

The specifications of the blower 1 of the first embodiment are as follows.
-Reliant angle θ formed by virtual line L1 and virtual line L3: 300 °
-Angle of the angle α formed by the virtual line L1 and the virtual line L2: 9 ° (about 1/30 of the dominant angle θ)
-Interval A: 0.1 to 0.15 times the outer diameter of the impeller 10-Interval B: 0.9 to 1.6 times the interval A-curvature of the tongue portion 33d: 0 of the outer diameter of the impeller 10 .05 times

  As shown in FIG. 6, the connecting portion 33e of the blower 1 according to the above specifications is located between the winding start point P1 of the spiral portion 33a and the impeller 10 of the tongue portion 33d, and is located on the upstream side of the spiral portion 33a from the imaginary line L1. ° Extends linearly in the moved range.

[Evaluation results]
7, the vertical axis represents the fan efficiency of the blower 1, the horizontal axis represents the interval B / interval A (B / A), and B / A is from 0.9 (Example 1) to 1.6 (Example 8). It is a graph which compared the fan efficiency with the fan efficiency of a conventional product.
The dotted lines in the horizontal direction in the graph indicate the fan efficiency of the conventional device, and (1) to (8) described near the eight rhombuses correspond to the fan efficiencies of Examples 1 to 8 below. The interval between the upper and lower lines in the graph is 1%.

  In Example 1, B / A was 0.9, and the interval A was longer than the interval B. Therefore, it is presumed that the pressure in the vicinity of the tongue portion 33d due to the recirculation air flow a2 increased more than that of the conventional product and the fan efficiency decreased.

  In Example 2, B / A was 1.0, and the distance B and the distance A were the same. However, since the connecting portion 33e is provided, the recirculation airflow a2 strikes the connecting portion 33e before flowing into the starting end position of the spiral ventilation passage 36, and then flows into the starting end position along the connecting portion 33e. Therefore, it was confirmed that the fan efficiency is slightly higher than that of the conventional product.

  In Example 3, B / A was 1.1, and the interval B was longer than the interval A. Therefore, the recirculation airflow a2 hits the connecting portion 33e before flowing into the starting end position of the spiral ventilation passage 36, and then flows into the starting end position along the connecting portion 33e, so that the fan efficiency is higher than that in the second embodiment. Was confirmed to increase.

  In Examples 4 and 5, B / A was 1.2 and 1.3, respectively, and the interval B was longer than that in Example 3. Therefore, as in the third embodiment, the recirculation airflow a2 hits the connecting portion 33e before flowing into the starting end position of the spiral ventilation passage 36, and then flows into the starting end position along the connecting portion 33e. It was confirmed that the fan efficiency was increased as compared with Example 3. In this evaluation result, the increase rate of the fan efficiency in Examples 4 and 5 was the best result.

  In Example 6, B / A is 1.4, the interval B is longer than in Example 5, and the slope is steeper, but the fan efficiency is the same as in Example 3 and higher than that in Example 2. Was confirmed. In the sixth embodiment, the gradient of the connecting portion 33e is steeper than that of the second to fifth embodiments. Therefore, when the recirculation airflow a2 hits the connecting portion 33e, this gradient acts and the fan is more fan than in the fourth and fifth embodiments. It is speculated that the efficiency has decreased.

  In Example 7, B / A was 1.5, the interval B was longer than in Example 5, and the gradient was steeper, but the fan efficiency was the same as in Example 2 and slightly increased as compared with the conventional product. Was confirmed. In the seventh embodiment, the gradient of the connecting portion 33e is steeper than that of the second to sixth embodiments. Therefore, when the recirculation air flow a2 hits the connecting portion 33e, this gradient acts and the fan efficiency is higher than that of the sixth embodiment. It is speculated that it has decreased.

  In Example 8, B / A was 1.6, the interval B was longer than that in Example 7, and the gradient was steepest. Therefore, when the recirculation airflow a2 hits the connecting portion 33e, the connecting portion 33e. It is presumed that the fan efficiency is deteriorated as compared with the conventional product due to the fact that it cannot be guided to the start end position of the swirl air passage 36 and the recirculated airflow a2 flows too much into the swirl air passage 36.

  From the above evaluation results, as a condition for providing the connecting portion 33e, the angle α of the angle formed by the imaginary line L1 and the imaginary line L2 is adjusted within the range of 5 ° ≦ α ≦ 20 °, and the relationship of the interval B / the interval A is further adjusted. Is in the range of 1.0 ≦ B / A ≦ 1.5, more preferably in the range of 1.1 ≦ B / A ≦ 1.4, and even more preferably in the range of 1.2 ≦ B / A ≦ 1.3. It has been confirmed that the fan efficiency is improved as compared with the conventional device by adjusting the interval.

DESCRIPTION OF SYMBOLS 1 ... Blower 10 ... Impeller 20 ... Electric motor 30 ... Casing 31 ... First side plate 32 ... Second side plate 33 ... Outer peripheral plate 33a ... Spiral part 33b ... Straight part 33c ... Extension part 33d ... Tongue part 33e ... Connection part 34 ... Suction port 35 ... Blowout port 36 ... Swirl ventilation passage 37 ... Blowout ventilation passage L1 to L3 ... Virtual line O ... Center of rotation of impeller P1 ... Winding start point P2 ... Winding end point

Claims (4)

An impeller that rotates about a rotating shaft to allow air to flow in from an axial end portion and to flow out from an outer peripheral portion,
A blow-out air passage having a spiral portion in which a spiral air passage is formed along the radially outer side of the impeller housed inside, and extending from the spiral portion and extending from the end portion of the spiral air passage toward the outlet. A casing in which is formed,
A tongue partitioning the start end position of the spiral air passage and the blowout air passage,
Equipped with
An inflow position of the second airflow, which is branched from the first airflow flowing from the blowout airflow path to the airflow outlet, toward the starting end position of the spiral airflow path in the vicinity of the tongue portion, A connecting portion that is separated from a starting end position of the spiral ventilation passage is provided between an impeller-side end portion of the tongue portion and a winding start point of the spiral portion.
Blower. The distance B from the impeller-side end of the tongue portion in the radial direction of the impeller to the outer peripheral portion of the impeller is determined from the winding start point of the spiral portion in the radial direction of the impeller of the impeller. The distance to the outer periphery is equal to or greater than the distance A,
The blower according to claim 1. A value of a ratio of lengths of the distance B and the distance A is 1.1 ≦ B / A ≦ 1.4.
The blower according to claim 2. An angle α formed by an imaginary line L1 connecting the rotation center of the impeller and the winding start point and an imaginary line L2 connecting the rotation center of the impeller and the end of the tongue on the impeller side is 5 ° ≦. The connecting portion is provided in a range of α ≦ 20 °,
The blower according to any one of claims 1 to 3.