JP2008157113A - Blower - Google Patents

Abstract

An object of the present invention is to enhance the noise reduction effect in forming a groove or protrusion for reducing blowing noise on a low pressure side blade surface of a blower blade of a blower.
In a blower having a plurality of blower blades, a plurality of grooves having linear edges inclined with respect to streamlines of airflow flowing along the low pressure side blade surface on the low pressure side blade surface of the blower blade, or Protrusions are provided.
The grooves or protrusions formed on each blower blade have a linear edge that is inclined with respect to the streamline of the airflow, so that the length of contact of the airflow with the inclined edge increases, The boundary layer peeling prevention effect is increased.
The grooves or protrusions may have the same inclination direction, or the inclination directions may cross each other.
The shape of the groove or protrusion is V-shaped or substantially V-shaped, and the V-shaped bent portion is directed to the upstream side or the downstream side of the air flow flowing along the low-pressure side blade surface of the blower blade. Can do.
[Selection] Figure 9

Description

  The present invention relates to a blower such as a propeller fan for an air conditioner.

  In general, in a blower such as a propeller fan for an air conditioner, as shown in FIG. 17, for example, a predetermined pitch is set on the outer periphery of a hub 3 fixed to a boss portion 1 connected to a rotation driving means such as a motor. Is configured by implanting a plurality of blades 2, 2... With a blade angle, and the blade row has a circumferential speed and a blade pitch from the root cross section toward the tip cross section of the blades 2, 2,. Is getting bigger.

  By the way, when the propeller fan rotates, noise of a predetermined level is generated. As the cause, for example, the following phenomenon is considered.

  That is, the air pressure of the low pressure side blade surface of each blade 2, 2... During rotation is high on the front side of the blade and low on the rear side, which is more remarkable depending on the degree of inclination of the blade itself toward the downstream side. It becomes. As a result, for example, as shown in FIG. 18, separation of the air flow occurs on the downstream low pressure surface side of the blade, and pressure variation occurs in the separation portion, resulting in deterioration of aerodynamic performance and noise.

  Therefore, as a countermeasure against this problem, for example, as shown in Japanese Patent Laid-Open No. 3-294699 (FIG. 1), a plurality of circular dimples are conventionally formed on the low-pressure surface side of the blade, and the dimple peeling-reducing action is achieved. As shown in Japanese Patent Application Laid-Open No. 2003-278696 (FIG. 3), the noise generation amount is reduced along the blade surface. There is known one having grooves or protrusions formed substantially parallel to the air flow (FIG. 20 of the present application).

JP-A-3-294699 (FIG. 1) Japanese Patent Laying-Open No. 2003-278696 (FIG. 3)

  Certainly, when a large number of dimples (reference numeral 111 in FIG. 19 of the present application) are provided on the low pressure surface side of the blade (reference numeral 102 in FIG. 19 of the present application) as in the above-mentioned Patent Document 1, a secondary flow is generated in the dimple. As a result, the flow velocity at the wall surface is recovered locally and the development of the boundary layer can be suppressed, so that the degree of flow separation is expected to decrease, the pressure fluctuation at the separation portion also decreases, and noise It is thought that it can contribute to reduction.

  On the other hand, as shown in Patent Document 2, in the case where grooves or protrusions (reference numeral 120 in FIG. 20 of the present application) are formed on the low-pressure blade surface of the blower blade, the formation direction of the grooves or protrusions 120 is air. Since it is parallel to the streamline of the flow, there is a problem that the length of the edge portion of the groove or the projection that affects the airflow cannot be obtained sufficiently.

  As described above, it is considered that the noise reduction effect is limited in the conventional configuration in which grooves or protrusions parallel to dimples and air flow streamlines are formed on the low pressure side blade surface of the blower blade.

  The present invention has been made in order to improve the problems in the prior art as described above. In a blower having a plurality of blower blades, the flow of air flowing along the low pressure side blade surface on the low pressure side blade surface of the blower blade is described. A basic configuration is that a large number of grooves or protrusions having linear edges inclined with respect to the streamline are provided.

  As described above, when a large number of grooves or protrusions having straight edges inclined with respect to the streamline of the air flow flowing along the low pressure side blade surface are provided on the low pressure side blade surface of the blower blade, As illustrated in FIG. 1 and in the case of a protrusion, as illustrated in FIG. 2, a local vortex U is generated near the surface of the blower blade, and the boundary layer is turbulent to form a turbulent boundary layer Wc. In this way, large peeling can be prevented.

  In that case, in the blower of the present invention, the grooves or protrusions formed on each blower blade have a straight edge inclined with respect to the streamline of the airflow, so that the airflow is in contact with the inclined edge. The above-mentioned boundary layer peeling preventing effect is increased.

  Further, in the above case, the grooves or protrusions may have the same inclination direction as illustrated in FIG. 3, and the inclination directions intersect with each other as illustrated in FIG. It may be said.

  Further, the groove or the projection is V-shaped or substantially V-shaped, and the V-shaped bent portion faces the upstream side or the downstream side of the airflow flowing along the low pressure side blade surface of the blower blade. (When the groove is V-shaped and the V-shaped bent portion faces the upstream side of the air flow, it is illustrated in FIG. 5, and when the V-shaped bent portion faces the downstream side of the air flow as well. Is illustrated in FIG. 6, and when the protrusion is V-shaped and its bent portion faces the upstream side of the airflow, it is exemplified in FIG. 7. Similarly, the V-shaped bent portion faces the downstream side of the airflow. The case is illustrated in FIG. 8).

  In the blower of the present invention, since the groove or projection formed on the low pressure side blade surface of the blower blade has a linear edge inclined with respect to the streamline of the airflow as described above, the edge of the groove or projection is in the airflow. On the other hand, the acting length is increased, and the effect of suppressing separation of the air flow from the low-pressure blade surface is increased. Also, when the groove or protrusion is V-shaped or substantially V-shaped, the apex of the V-shape acts as a wedge-shaped vortex generator (vortex generator), so that the blade boundary layer is effectively Energy can be provided, large peeling can be suppressed, and blowing noise can be reduced.

  Next, preferred embodiments of the blower of the present invention will be described with reference to the accompanying drawings.

First embodiment (FIG. 9)
The blower of the first embodiment shown in FIG. 9 has three identical fan blades 2, 2, 2 at equiangular intervals around the boss portion 1, and is illustrated in FIG. 3 on the low pressure side blade surface of each fan blade. Are formed in parallel to each other at a depth of 0.25 to 0.3 mm (in addition, contact between the edge of each groove and the streamline of the air flow W) The corners are the same). In the blower of the first embodiment, the turbulence of the air flow as described in the action explanatory diagram illustrated in FIG. 1 occurs on the low pressure side blade surfaces of the blower blades 2, 2, and 2, and the turbulent boundary layer is thereby generated. The air blowing noise is reduced by Wc.

Second embodiment (FIG. 10)
The blower of the second embodiment shown in FIG. 10 has three identically shaped blower blades 2, 2, and 2 at equal intervals around the boss portion 1 as in the blower shown in FIG. A large number of grooves 11, 11,..., 12, 12,... Having a depth of 0.25 to 0.3 mm are formed on the surface in directions intersecting with each other as illustrated in FIG. (Incidentally, the contact angle between each groove 11, 11... Inclined in the same direction and the stream line of the air flow W and each groove 12 inclined in the same direction crossing the grooves 11, 11. , 12... And the streamlines of the air flow W are the same).

Third embodiment (FIG. 11)
The blower of the third embodiment shown in FIG. 11 has three fan blades 2, 2, 2 having the same shape around the boss portion 1 at equal angular intervals, like the blower of the first embodiment. .. Of V-shaped grooves 10, 10... Having a depth of 0.25 to 0.3 mm as illustrated in FIG. 5 on the low-pressure side blade surface, and the V-shaped bent portion 17 faces the upstream side of the air flow. In this way, it is formed.

Fourth embodiment (FIG. 12)
The blower of the fourth embodiment shown in FIG. 12 has, in the same manner as the blower of the first embodiment, three identically shaped fan blades 2, 2, 2 around the boss portion 1 at equal angular intervals. .. Of V-shaped grooves 10, 10... Having a depth of 0.25 to 0.3 mm as illustrated in FIG. 6, and the V-shaped bent portion 17 faces the downstream side of the air flow. In this way, it is formed.

Example 5 (FIG. 13)
The blower of the fifth embodiment shown in FIG. 13 has three fan blades 2, 2, 2 having the same shape around the boss portion 1 at equal angular intervals, like the blower of the first embodiment. The V-shaped protrusions 20, 20... Having a height of 0.25 to 0.3 mm as illustrated in FIG. 7 are arranged on the low-pressure side wing surface so that the V-shaped bent portion 27 faces the upstream side of the air flow. Is formed.

Sixth embodiment (FIG. 14)
The blower of the sixth embodiment shown in FIG. 14 has three fan blades 2, 2, 2 having the same shape around the boss portion 1 at equal angular intervals, like the blower of the first embodiment. The V-shaped protrusions 20, 20... Having a height of 0.25 to 0.3 mm as illustrated in FIG. 7 are arranged on the low-pressure side blade surface of the blade so that the V-shaped bent portion 27 faces the downstream side of the air flow. Is formed.

  In the third to sixth embodiments, each groove 10 or each projection 20 is formed in such a direction that its V-shaped center line coincides with the stream line of the air flow W.

Seventh embodiment (FIGS. 15 and 16)
Each of the blowers of the first to sixth embodiments was a propeller fan having three blower blades 2, 2, 2 around the boss portion 1, but the present invention is only such a propeller fan. For example, the present invention can be applied to the blower blades of a turbo fan (FIG. 16) and the blower blades (not shown) of a cross flow fan as illustrated in FIG. It is possible to form various grooves or protrusions as illustrated in FIGS. 15 and 16, reference numeral 50 denotes a motor, 51 denotes a boss portion, 52 and 52 denote blower blades, and 60 denotes a V-shaped groove or protrusion.

It is explanatory drawing of an air action at the time of forming a groove | channel in the ventilation blade of the air blower of this invention. It is explanatory drawing of an air action at the time of forming a protrusion in the ventilation blade of the air blower of this invention. It is explanatory drawing of the example of arrangement | sequence of the groove | channel or protrusion formed on the ventilation blade of the air blower of this invention. It is explanatory drawing of the other example of arrangement | sequence of the groove | channel or protrusion formed on the ventilation blade of the air blower of this invention. It is explanatory drawing of the example of arrangement | sequence of the V-shaped groove | channel formed on the ventilation blade of the air blower of this invention. It is explanatory drawing of the other example of arrangement | sequence of the V-shaped groove | channel formed on the ventilation blade of the air blower of this invention. It is explanatory drawing of the example of arrangement | sequence of the V-shaped protrusion formed on the ventilation blade of the air blower of this invention. It is explanatory drawing of the other example of arrangement | sequence of the V-shaped protrusion formed on the ventilation blade of the air blower of this invention. It is shape explanatory drawing of the air blower concerning 1st Example of this invention. It is shape explanatory drawing of the air blower concerning 2nd Example of this invention. It is shape explanatory drawing of the air blower concerning 3rd Example of this invention. It is shape explanatory drawing of the air blower concerning 4th Example of this invention. It is shape explanatory drawing of the air blower concerning 5th Example of this invention. It is shape explanatory drawing of the air blower concerning 6th Example of this invention. It is fan explanatory drawing at the time of implementing this invention for a turbofan. FIG. 16 is a diagram illustrating a shape example of a blower blade in the turbo fan illustrated in FIG. 15. It is explanatory drawing of the example of a shape of a conventionally well-known air blower. It is explanatory drawing of the airflow on the ventilation blade in the well-known air blower shown in FIG. It is composition explanatory drawing of the blade surface in an example of a conventionally well-known air blower. It is composition explanatory drawing of the blade surface in an example of another conventionally well-known air blower.

Explanation of symbols

  1 is a boss portion, 2 is a blower blade, 10, 11 and 12 are grooves or protrusions, 17 is a V-shaped bent portion, 20 is a V-shaped protrusion, and 27 is a V-shaped bent portion.

Claims (10)

  A blower provided with a plurality of blower blades, wherein a plurality of grooves having linear edges inclined with respect to streamlines of airflow flowing along the low pressure side blade surface are provided on the low pressure side blade surface of the blower blade. A blower characterized by that.   The blower according to claim 1, wherein the grooves are inclined in the same direction.   The blower according to claim 1, wherein the inclination directions of the grooves intersect with each other.   The blower according to claim 1, wherein the groove is substantially V-shaped, and the V-shaped bent portion faces the upstream side of the air flow flowing along the low-pressure blade surface of the blower blade.   The blower according to claim 1, wherein the groove is substantially V-shaped, and the V-shaped bent portion faces the downstream side of the air flow flowing along the low-pressure blade surface of the blower blade.   A blower provided with a plurality of blower blades, wherein a plurality of protrusions having a linear edge inclined with respect to a streamline of an air flow flowing along the low pressure side blade surface are provided on the low pressure side blade surface of the blower blade. A blower characterized by that.   The blower according to claim 6, wherein the inclination directions of the protrusions are the same.   The blower according to claim 6, wherein the inclination directions of the protrusions intersect with each other.   The blower according to claim 6, wherein the protrusion is substantially V-shaped, and the V-shaped bent portion faces the upstream side of the air flow flowing along the low-pressure blade surface of the blower blade.   The blower according to claim 6, wherein the protrusion is substantially V-shaped, and the V-shaped bent portion faces the downstream side of the airflow flowing along the low-pressure blade surface of the blower blade.

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