JP6215296B2 - Propeller fan and air conditioner equipped with the same - Google Patents

Description

  The present invention relates to a propeller fan and an air conditioner including the same.

  Propeller fans are often used in air conditioners and the like. FIG. 13 shows a plan view of a propeller of a conventional propeller fan. FIG. 13 is a view of the propeller viewed from the discharge side. The propeller is composed of a plurality of wings provided around the hub. In order to reduce noise, the wing often adopts a shape that advances the wing in the rotational direction (forward wing). The forward wing has the effect of reducing the tip vortex flowing out from the tip, and has the effect of reducing noise.

  As a background art in this technical field, there is Japanese Patent Publication No. 2-2000 (Patent Document 1). In Patent Document 1, it is possible to increase the air volume, increase the static pressure, and reduce noise by numerically limiting the shape parameters such as the degree of blade advancement, blade inclination, and blade section warpage in the above-described forward blade. Have been described.

  Moreover, there exists patent 3744489 (patent document 2). Patent Document 2 describes that noise can be reduced by reducing the blade tip vortex by causing the outer peripheral end of the blade to warp toward the suction side. Furthermore, it is described that by defining such a positional relationship between the wing and the bell mouth, it is possible to suppress the interference between the airflow and the bell mouth and reduce noise.

  Furthermore, there exists patent 4818184 (patent document 3). In Patent Document 3, the wing tip vortex is moved to the inside of the blade outer periphery by causing the blade to warp to the suction side in a different definition method from Patent Document 2, preventing interference between the blade tip vortex and the bell mouth, It describes that noise reduction and high efficiency can be achieved.

JP2000-2000 Japanese Patent No. 3744489 Japanese Patent No. 4818184

  In the embodiment, the force acting on the flow by the blade is referred to as “blade force”. In FIG. 13, the blade force acting on the flow of the blade is indicated by an arrow A '. In the propeller of a conventional propeller fan, since the blade has a shape advanced in the rotation direction, the blade force acts in the inner circumferential direction with respect to the direction of the rotation shaft 6 as indicated by an arrow A '. Due to the blade force in the inner circumferential direction, the flow obtains a momentum in the inner circumferential direction, so that the flow is directed in the inner circumferential direction.

FIG. 14 is a schematic diagram of velocity vectors projected on a cross section passing through the rotary shaft 6 in a conventional propeller fan. As shown in FIG. 14, since the flow is directed in the inner circumferential direction, the flow is not supplied in the vicinity of the bell mouth arranged so as to cover the outer periphery of the propeller fan, although not shown. As a result, the air velocity in the vicinity of the bell mouth decreases. If the flow is not supplied in the vicinity of the bell mouth, the speed at the exit of the wing and the exit of the bell mouth becomes non-uniform, which is a problem in improving the efficiency of the propeller fan.
Therefore, an object of the present invention is to improve the efficiency of the propeller fan.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present application includes a plurality of means for solving the above-described problems. For example, the present application includes a rotation shaft serving as a rotation center and a plurality of blades provided around the rotation shaft, In the propeller fan in which a bell mouth is disposed on the outer circumferential direction of the wing, each of the plurality of wings includes a rear edge portion formed rearward with respect to the rotation direction and a front edge formed with respect to the rotation direction. A meridian formed by rotation and projected onto a plane passing through the rotation axis, and a wing tip formed from an outer edge of the rear edge to an outer edge of the front edge. The trailing edge of the surface is formed to bend with a first curvature from the suction side to the discharge side from the rotating shaft toward the blade tip, and further, through the inflection point, the first Formed to bend with a second curvature smaller than the curvature of 1 Characterized in that it is.

Further, in the above configuration, at the end face closest to the wing of the bell mouth, the position at which the angle changes in the discharge direction and in the outer circumferential direction is substantially as seen from the position of the inflection point and the rotation surface. It is desirable to match.
In the above configuration, the trailing edge portion projected onto a plane perpendicular to the rotation axis is formed in a convex shape in the counter-rotation direction from the rotation axis toward the blade tip portion, and further via an inflection point. Thus, it is desirable to form a straight line or a convex shape in the rotational direction.

Further, in the above-described configuration, each of the plurality of blades has a blade force at a portion formed by the first curvature in the rear edge portion so as to go in the outer circumferential direction with respect to the rotation axis direction. While acting, it is desirable that a blade force acts on a portion formed by the second curvature of the rear edge portion so as to be directed in an inner circumferential direction with respect to the rotation axis direction.
Further, in the above configuration, it is desirable to provide a guard that allows air to pass through the discharge side of the blade and prevents contamination of foreign matters of a predetermined size or more and that is separated from the propeller by a predetermined length or more.
Further, a housing having an air inlet and an air outlet, a heat exchanger disposed in the housing, and an upstream or downstream side of the heat exchanger, the air outside the housing is drawn into the suction port In an air conditioner provided with a fan that sucks more and blows out from the air outlet, it is desirable to use the propeller fan according to any one of the above-described configurations for the fan.

  According to the present invention, high efficiency of the propeller fan can be realized.

Sectional drawing of the plane which passes along the rotating shaft of the propeller fan of Example 1 The figure explaining the difference in the blade force in the propeller fan of Example 1, and the propeller fan of a prior art example Schematic diagram of the velocity vector projected on the cross section passing through the rotation axis in the propeller fan of Example 1 Sectional drawing of the plane which passes along the rotating shaft of the propeller fan of Example 2 Schematic diagram of the velocity vector projected on the cross section passing through the rotation axis in the propeller fan of Example 2 Example of comparison of shaft power between propeller fan and conventional propeller fan in Example 2 The figure which shows the combination with the bell mouth of the shape different from FIG. 4 in Example 2. The figure which shows the combination with the bell mouth of the shape different from FIG. 4 in Example 2. 6 is a plan view of a propeller in Example 3. FIG. Figure of propeller fan in Example 4 Example of comparison of noise between propeller fan in embodiment 4 and conventional propeller fan Sectional drawing of the air conditioner in Example 5 Top view of conventional propeller fan propeller Schematic diagram of velocity vector projected on a cross section passing through the rotation axis in a conventional propeller fan

  Embodiments of the present invention will be described below with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a cross-sectional view of a plane passing through the rotation axis of the propeller fan according to the first embodiment. 1 denotes a blade, 2 denotes a hub, 3 denotes a trailing edge, 4 denotes a leading edge, 5 denotes a blade tip, 6 denotes a rotation axis serving as a rotation center, and X denotes an air flow direction. The trailing edge 3 is formed rearward with respect to the rotation direction of the blade 1, and the leading edge 4 is formed forward with respect to the rotation direction of the blade 1. The blade tip 5 is formed from the circumferential tip of the trailing edge 3 to the circumferential tip of the leading edge 4.

  In FIG. 1, the rear edge portion 3 shows a rotational projection onto a plane passing through the rotation axis 6. The trailing edge 3 is formed from the rotating shaft 6 toward the blade tip 5 so as to bend from the suction side to the discharge side with the first curvature α. Further, it is formed so as to bend with a second curvature β smaller than the first curvature α via the inflection point 7.

  FIG. 2 is a diagram for explaining a difference in blade force between the propeller fan of the first embodiment and the propeller fan of the conventional example. FIG. 2 is a view of the propeller fan as viewed from an oblique side. A shows the blade force which the part 3b of the 2nd curvature (beta) in the trailing edge part 3 of the propeller fan of Example 1 acts. A 'represents the blade force acting on the trailing edge 3b' on the blade tip 5 'side of the propeller fan of the conventional example. Y indicates the direction of rotation of the wing.

  Since the blade 1 of the propeller fan according to the present embodiment has the above-described configuration, the blade force A acts toward the outer peripheral direction with respect to the direction of the rotating shaft 6. For this reason, the flow in the vicinity of the rear edge 3b partially obtains a momentum that goes in the outer circumferential direction with respect to the direction of the rotation shaft 6. On the other hand, the blade force A ′ of the conventional propeller fan acts in the inner circumferential direction with respect to the direction of the rotating shaft 6. Therefore, the flow between the blades obtains a momentum that goes in the inner circumferential direction with respect to the direction of the rotating shaft 6.

  FIG. 14 is a schematic diagram of a velocity vector projected on a cross section passing through the rotation axis in a conventional propeller fan. Due to the blade force A 'directed in the inner circumferential direction with respect to the direction of the rotating shaft 6 in FIG. 2, the flow T in FIG. 14 is directed in the inner circumferential direction in order to obtain a momentum in the inner circumferential direction. Accordingly, although not shown, no flow is supplied to the vicinity of the bell mouth arranged so as to cover the outer peripheral direction of the propeller fan, and the speed near the bell mouth is reduced. The fact that no flow is supplied in the vicinity of the bellmouth means that the flow U is stagnant. Then, the flow U and the flow T in the vicinity of the bell mouth become non-uniform in speed on the exit side of the blade, which may cause a reduction in efficiency.

  FIG. 3 is a schematic diagram of velocity vectors projected on a cross section passing through the rotation axis in the propeller fan of the first embodiment. Due to the action of the blade force A in FIG. 2, the flow in the vicinity of the blade tip 5 is directed toward the outer periphery with respect to the rotating shaft 6 as in the flow S in FIG. That is, according to the shape of the trailing edge portion 3 of the present embodiment, a portion of the trailing edge portion 3 formed with the first curvature α is directed to the outer peripheral direction with respect to the direction of the rotating shaft 6. While the force A acts, the blade force acts on the portion formed by the second curvature β in the rear edge portion 3 so as to be directed in the inner circumferential direction with respect to the direction of the rotation shaft 6. .

  As a result, in the prior art, the flow was not supplied in the vicinity of the bell mouth as shown in FIG. Can be suppressed. Accordingly, the speed in the vicinity of the blade outlet can be made uniform, and the mixing loss of the blade wake can be reduced, so that the efficiency can be increased.

In the present embodiment, an embodiment that can further improve the efficiency of the first embodiment will be described with reference to FIGS.
FIG. 4 is a cross-sectional view of a plane passing through the rotation axis of the propeller fan according to the second embodiment. 8 indicates a bell mouth, 9 indicates a cylindrical portion, and 10 indicates an end portion of the bell mouth. The cylindrical portion 9 is a part of the bell mouth 8 and covers the wing 1 through a predetermined clearance. The end portion 10 is an end portion on the discharge side of the cylindrical portion 9, and in FIG. 1, the end portion 10 is located at a position where the angle changes at a right angle to the outer circumferential direction, and the end portion 10 is arranged to coincide with the inflection point 7 when viewed from the rotation surface. .

  That is, at the end face closest to the wing 1 of the bell mouth 8, the position of the end portion 10 in the discharge direction and the angle changing in the outer peripheral direction is made to substantially coincide with the position of the inflection point 7 when viewed from the rotation surface. ing. As a result, at the end face closest to the wing 1 of the bell mouth 8, the position where the angle changes in the outer circumferential direction at the end portion 10 in the discharge direction is the portion where the outward wing force A acts and the outward wing force. It substantially coincides with the position that becomes the boundary of the portion where A does not act as seen from the surface of rotation.

  FIG. 5 is a schematic diagram of velocity vectors projected on a cross section passing through the rotation axis in the propeller fan of the second embodiment. Since the end portion 10 and the inflection point 7 are arranged substantially coincident with each other, the velocity distribution made uniform by the action of the blade force in the direction of arrow A shown in FIG. Is retained without being diffused. Therefore, the operational effects of Example 1 can be obtained more reliably, and the efficiency of the propeller fan can be increased.

  FIG. 6 shows a comparison result of shaft power between the propeller fan in Example 2 and the conventional propeller fan. In the vicinity of the operating point, the power consumption of the propeller fan of the second embodiment is 3.3% energy saving, that is, higher efficiency than the conventional propeller fan.

  7 and 8 are diagrams showing a combination with a bell mouth having a shape different from that in FIG. 4 in the second embodiment. In the bell mouth of FIG. 7, the discharge side of the cylindrical portion 9 has an arc shape. In this case, the end portion 10a becomes a contact point between the straight line of the cylindrical portion 9 and the circular arc. The bell mouth of FIG. 8 has a conical taper on the discharge side of the cylindrical portion 9. In this case, the end portion 10b serves as a contact point between the straight line of the cylindrical portion 9 and the conical taper. As shown in the drawing, the end portions 10a and 10b are arranged so as to coincide with the inflection point 7 when viewed from the rotation surface. The effects obtained by the present invention can be the same as those of the bell mouse of FIG. 4 in any of the bell mice of FIGS.

In the present embodiment, an embodiment that can further improve the efficiency of the first or second embodiment will be described with reference to FIGS. 9 and 10.
FIG. 9 is a plan view of the propeller according to the third embodiment. FIG. 9 is a view of the propeller viewed from the discharge side. In FIG. 9, the trailing edge 3 is projected on a plane perpendicular to the rotation axis. The trailing edge portion 3 is formed in a convex shape in the counter-rotating direction from the hub 2 toward the blade tip portion 5, and is formed in a convex shape in the rotating direction via the inflection point 18. B represents the blade force acting near the rear edge 3h of the hub 2 side, and C represents the blade force acting near the rear edge 3t on the blade tip 5 side. It is desirable that the inflection point 18 has the same radius as the inflection point 7 described in the first and second embodiments.

  Since the curvature of the trailing edge 3t has changed at the inflection point 18, the blade force C changes its direction in the outer circumferential direction relative to the direction of the rotary shaft 6 compared to the blade force B. Due to this change in the direction of the blade force, the flow in the vicinity of the trailing edge 3t obtains a momentum in the outer circumferential direction, and the flow in the vicinity of the blade tip 5 becomes in the outer circumferential direction. As a result, the speed near the blade outlet is made uniform. The efficiency is increased because the mixing loss of the wake of the blade is reduced by the uniform speed.

  In FIG. 9, the trailing edge 3 t is formed to be convex in the rotational direction, but the curvature of the trailing edge 3 t is larger than the trailing edge 3 h via the inflection point 18. Furthermore, the same effect | action mentioned above can be acquired by changing to linear form further.

In the present embodiment, in addition to the high efficiency of the first to third embodiments, an embodiment capable of obtaining the effect of reducing noise will be described with reference to FIGS. 10 and 11.
FIG. 10 is a diagram of the propeller fan in the fourth embodiment. FIG. 10 shows a case where a guard is disposed on the wake side of the blades of the propeller fans of the first to third embodiments. The guard is formed in a cross shape or a net shape so as to allow air to pass through to the discharge side of the wing, and a foreign matter having a predetermined size or more is prevented by the gap between the cross and the net. The speeds near the blade outlets of the propeller fans of Examples 1 to 3 are made uniform as compared with the conventional propeller fan. Since the noise caused by the flow is proportional to the sixth power of the flow velocity, the noise generated from the guard 11 is dominant when the speed is locally high. Therefore, in the third embodiment in which the speed is made uniform, noise is reduced as compared with a combination with a conventional propeller fan.

  FIG. 11 shows an example of noise comparison between the propeller fan in the third embodiment and the conventional propeller fan. It has been confirmed that the noise of the propeller fan in Example 3 is reduced by about 1 dB compared to the conventional propeller fan.

  It should be noted that the guard 11 needs to have a predetermined size or less so that adult fingers do not enter the gaps between the bars and the net. Furthermore, it is necessary to prevent the propeller 12 from being touched even when a child's finger enters the gap of the guard 11. Therefore, further safety can be ensured by setting the distance L between the rear edge 3 and the position 19 closest to the guard 11 from the end of the crosspiece or net of the guard 11 to a predetermined length or more. Since the length of a child's finger is assumed to be about 50 mm, it is desirable to secure a distance L of 50 mm or more.

A present Example demonstrates the air conditioner using the propeller fan provided with the requirements in any one of Examples 1-4.
FIG. 12 is a cross-sectional view of the air conditioner according to the fifth embodiment. This air conditioner is an outdoor unit. In FIG. 12, the propeller 12 is fixed and supported by a motor 13 and a motor support base 14 and rotates. A bell mouth 8 is disposed on the outer periphery of the propeller 12. A guard 11 is disposed in the downstream area. Inside the unit 15, a heat exchanger 16 is installed upstream of the propeller 12. A compressor 17 is mounted inside the unit 15.

  In this air conditioner, the propeller 12 is rotated by a motor 13 so that air is sucked into the heat exchanger 16, cooled or overheated, then pressurized by the propeller 12 and the bell mouth 8, and then discharged from the guard 11. . Since the propeller fan described in any of Examples 1 to 4 is used for the propeller fan and the bell mouth, an air conditioner with low noise and high efficiency can be obtained.

  Although the outdoor unit has been described in the present embodiment, the present invention is a technique that can be used in common as long as the air conditioner uses another type or an indoor unit and uses a propeller fan.

1, 1 'wing 2, 2' hub 3, 3 ', 3t, 3h trailing edge 4, 4' leading edge 5, 5 'wing tip 6, 6' rotation center 7 inflection point 8 bellmouth 9 cylinder 10, 10 a, 10 b End 11 Guard 12 Propeller 13 Motor 14 Motor support 15 Unit 16 Heat exchanger 17 Compressor 18 Inflection point 19 The rear edge 3 and the guard 11 are the most from the end of the guard 11 bar or net. Approaching position A, A ′ Blade force B Blade force C Blade force L Distance S Flow T Flow U Flow X Air flow direction Y Rotational direction α First curvature β Second curvature

Claims (6)

A rotation axis as a center of rotation;
A plurality of wings provided around the rotating shaft,
In the propeller fan in which a bell mouth is disposed on the outer periphery side of the plurality of wings,
Each of the plurality of wings is
A rear edge portion formed rearward with respect to the rotation direction, a front edge portion formed forward with respect to the rotation direction, and a front edge portion in the outer peripheral direction of the front edge portion from the front end portion in the outer peripheral direction of the rear edge portion A wing tip formed toward the
The trailing edge portion of the meridional surface that is rotationally projected onto a plane passing through the rotation axis is bent in a convex shape with a first curvature from the suction axis toward the wing tip portion from the suction side to the discharge side. A propeller fan, characterized in that the propeller fan is formed so as to be bent in a convex shape with a second curvature smaller than the first curvature via an inflection point. A rotation axis as a center of rotation;
A plurality of wings provided around the rotating shaft,
In the propeller fan in which a bell mouth is disposed on the outer periphery side of the plurality of wings,
Each of the plurality of wings is
A rear edge portion formed rearward with respect to the rotation direction, a front edge portion formed forward with respect to the rotation direction, and a front edge portion in the outer peripheral direction of the front edge portion from the front end portion in the outer peripheral direction of the rear edge portion A wing tip formed toward the
The trailing edge portion that is rotationally projected onto a plane passing through the rotating shaft is formed so as to bend with a first curvature from the suction side to the discharge side from the rotating shaft toward the blade tip portion. Formed through a point of curvature with a second curvature smaller than the first curvature,
In the end face closest to the wing of the bell mouth, the position in the discharge direction and the position where the angle changes in the outer peripheral direction substantially coincides with the position of the inflection point when viewed from the rotation surface. Propeller fan. In claim 1,
The trailing edge portion projected onto a plane perpendicular to the rotation axis is formed in a convex shape in the counter-rotation direction from the rotation axis toward the blade tip, and further formed in a straight line via an inflection point. Propeller fan, characterized by In any one of Claims 1-3,
Each of the plurality of wings is
A wing force acts on the portion formed by the first curvature of the rear edge portion so as to go to the outer peripheral direction with respect to the rotation axis direction, and
A propeller fan characterized in that a blade force acts on a portion of the rear edge portion formed by the second curvature so as to be directed in an inner circumferential direction with respect to the rotation axis direction. In any one of Claims 1-4,
A propeller fan characterized by comprising a guard that allows air to pass through the discharge side of the blades and prevents foreign substances having a predetermined size or more from being mixed, and is separated from the propeller by a predetermined length or more. A housing having an air inlet and an air outlet;
A heat exchanger disposed in the housing;
In an air conditioner comprising: a fan arranged on the upstream side or the downstream side of the heat exchanger, sucking air outside the housing from the suction port, and blowing out from the blowout port,
An air conditioner using the propeller fan according to any one of claims 1 to 4 as the fan.

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