JP2019052539A - Axial blower - Google Patents

Abstract

To provide an axial blower which can reduce noise at the rotation of an impeller.SOLUTION: In a plurality of blades 24 of an impeller 20, auxiliary blade parts 25 progressing toward a rotation direction AR of a rotating shaft 11 are arranged in regions in which circular virtual circumferential lines VCL for connecting the plurality of the blades 24 and front edge parts 24a of the blades 24 intersect with each other. The auxiliary blade parts 25 have auxiliary front edge parts 251 extending from root regions 25a intersecting with the front edge parts 24a to tip regions 25b intersecting with the virtual circumferential lines VCL. Then, the auxiliary front edge parts 251 have forms which are bent so as to approximate the virtual circumferential lines VCL as compared with virtual linear lines VSL which at least partially and linearly connect the root regions 25a and the tip regions 25b.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an axial blower that blows air along the axis of a rotating shaft.

  2. Description of the Related Art Conventionally, in an axial blower, a configuration is known in which a portion advanced in the rotational direction is provided at the front edge of a blade in order to reduce noise (see, for example, Patent Document 1). In Patent Document 1, by installing a V-shaped cut shape on the outer peripheral side of the front edge of the blade, vortices generated at the outer peripheral end of the blade and from the inner peripheral side to the outer peripheral side generated on the surface of the blade. The structure which suppresses interference with the airflow which heads is disclosed.

JP 2014-62534 A

  According to the study by the present inventors, when a V-shaped cut shape is simply installed on the outer peripheral side of the front edge of the blade, the portion advanced in the rotational direction on the outer peripheral side of the front edge of the blade and the outer periphery of the blade It was found that noise was produced by interference with the vortex generated on the side.

  In view of the above points, an object of the present invention is to provide an axial blower capable of reducing noise during rotation of an impeller.

  The invention described in claim 1 is directed to an axial blower that blows air along the axis (SC) of the rotating shaft (11).

  In order to achieve the above object, the invention according to claim 1 has a plurality of blades (24) arranged radially with respect to the axis of the rotating shaft, and rotates around the axis of the rotating shaft. And an impeller (20) for generating an air flow. The plurality of blades are advanced in the rotation direction (AR) of the rotation shaft at a portion where a circular virtual circumferential line (VCL) connecting the outer peripheral side ends of the plurality of blades and the front edge (24a) of the blade intersect. The auxiliary wings (25, 25A) are formed. The auxiliary wing portion has auxiliary front edge portions (251, 251A) extending from a root portion (25a) intersecting with the front edge portion to a tip portion (25b) intersecting with the virtual circumferential line. The auxiliary front edge portion is bent at least partially so as to be closer to the virtual circumferential line than a virtual straight line (VSL) that linearly connects the root portion and the tip portion.

  In this way, if the shape of the auxiliary front edge portion is bent so as to be close to the virtual circumferential line connecting the outer peripheral side ends of the plurality of blades, the vortex generated at the outer peripheral side ends of the plurality of blades Interference with the auxiliary front edge can be suppressed. Thereby, since the pressure fluctuation of the air in the outer peripheral side of a some braid | blade is suppressed, it becomes possible to aim at reduction of the noise of an axial flow fan at the time of rotation of an impeller.

  In addition, the code | symbol in the parenthesis of each means described in this column and the claim shows an example of a correspondence relationship with the specific means described in the embodiment described later.

It is a typical front view of the axial-flow fan of 1st Embodiment. It is II-II sectional drawing of FIG. It is a typical front view which shows the braid | blade and boss | hub part of the axial-flow fan of 1st Embodiment. It is a typical front view of the blade of the axial blower of a 1st embodiment. It is a typical front view for demonstrating the detail of the braid | blade of the axial flow fan of 1st Embodiment. It is a typical front view which shows the airflow of the outer peripheral side edge part in the braid | blade of the axial-flow fan of a comparative example. It is a characteristic view which shows the measurement result of the sound pressure level of the axial-flow fan of 1st Embodiment, and the axial-flow fan of a comparative example. It is a characteristic view which shows the fall amount of the sound pressure level with respect to the axial-flow fan of the comparative example in the axial-flow fan of 1st Embodiment. It is a typical front view of the blade of the axial blower of a 2nd embodiment. It is a characteristic view which shows the fall amount of the sound pressure level with respect to the axial-flow fan of the comparative example in the axial-flow fan of 2nd Embodiment. It is a typical front view which shows the modification of the braid | blade of the axial-flow fan of 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts as those described in the preceding embodiments are denoted by the same reference numerals, and the description thereof may be omitted. Further, in the embodiment, when only a part of the constituent elements are described, the constituent elements described in the preceding embodiment can be applied to the other parts of the constituent elements. The following embodiments can be partially combined with each other even if they are not particularly specified as long as they do not cause any trouble in the combination.

(First embodiment)
The axial-flow fan 1 of this embodiment is demonstrated with reference to FIGS. In each drawing, the illustrated arrow DR1, arrow DR2, and arrow DR3 indicate directions when the axial blower 1 is mounted on a vehicle. That is, the arrow DR1 indicates the vehicle vertical direction, the arrow DR2 indicates the vehicle left-right direction (that is, the vehicle width direction), and the arrow DR3 indicates the vehicle front-rear direction. Moreover, AR shown in each drawing has shown the rotation direction of the impeller 20 mentioned later.

  As shown in FIGS. 1 and 2, the axial blower 1 is a blower that blows air along the axis SC of the rotating shaft 11. In the present embodiment, an example will be described in which the axial blower 1 is applied to a device that supplies air to a radiator 2 such as a radiator mounted on a vehicle. In FIG. 2, the radiator 2 is indicated by a one-dot chain line in order to display the axial blower 1 in an easily viewable manner.

  The axial blower 1 of the present embodiment is disposed behind the radiator 2 than the radiator 2. Specifically, the axial blower 1 is provided on the downstream side of the air flow passing through the radiator 2 so that the air that has passed through the radiator 2 is blown out to the rear of the vehicle.

  The axial blower 1 of the present embodiment includes an electric motor 10, an impeller 20 that generates an airflow by rotating with the rotating shaft 11 of the electric motor 10, and a shroud 30 that holds the electric motor 10.

  The electric motor 10 is an electric motor that rotationally drives the impeller 20. The electric motor 10 is fixed to the shroud 30 via a stay (not shown). The stay is a support member that supports the electric motor 10.

  The impeller 20 is connected to the rotation shaft 11 and rotates around the axis SC as the rotation shaft 11 rotates. The impeller 20 includes a boss portion 22 connected to rotate integrally with the rotary shaft 11 of the electric motor 10, a plurality of blades 24 extending radially with respect to the axis SC of the rotary shaft 11, and a plurality of blades 24. It has the ring part 28 provided in the outer peripheral part.

  The boss 22 is a cylindrical member with the rotating shaft 11 of the electric motor 10 attached to the center. The boss portion 22 has an inner peripheral side end portion of each of the plurality of blades 24 connected to the outer peripheral side of the side wall thereof.

  The plurality of blades 24 extend radially from the boss portion 22. The plurality of blades 24 are arranged around the boss portion 22 with a predetermined interval. Each of the plurality of blades 24 of the present embodiment is a retracted wing.

  Here, FIG. 3 shows the impeller 20 shown with the ring portion 28 omitted. As shown in FIG. 3, the rotation direction of the rotating shaft 11 is provided at a portion where the virtual circumferential line VCL connecting the outer peripheral side ends of the plurality of blades 24 and the front edge portion 24 a of the blade 24 intersect each other. An auxiliary wing 25 that has advanced to the AR is formed. The details of the blade 24 of the impeller 20 will be described later.

  Returning to FIGS. 1 and 2, the ring portion 28 is formed in an annular shape centering on the axis SC of the rotating shaft 11 so as to connect the outer peripheral side ends of the plurality of blades 24 in the circumferential direction. In other words, the ring portion 28 is configured by an annular member extending along a virtual circumferential line VCL connecting the outer peripheral side ends of the plurality of blades 24.

  In the impeller 20 of this embodiment, the boss portion 22, the plurality of blades 24, and the ring portion 28 are each made of a resin such as polypropylene. And the boss | hub part 22, the some braid | blade 24, and the ring part 28 are comprised as an integral molded product.

  The shroud 30 is a member that functions as a duct that guides the air that has passed through the radiator 2 to the impeller 20. The shroud 30 of this embodiment is being fixed to the heat radiator 2 with fastening members, such as a volt | bolt. Moreover, the shroud 30 of this embodiment is comprised with resin, such as a polypropylene.

  The shroud 30 is formed with an air inlet 31 for introducing air and an air outlet 32 for blowing air from the air inlet 31. A space from the air inlet 31 to the air outlet 32 in the shroud 30 constitutes an air ventilation path 30a.

  The air introduction port 31 faces the radiator 2 and opens in a direction along the axis of the rotary shaft 11. Specifically, the air inlet 31 has a rectangular shape in which the dimension in the vehicle width direction DR2 is longer than the dimension in the vehicle vertical direction DR1 in accordance with the outer shape of the radiator 2.

  The air blower outlet 32 has the impeller 20 disposed therein. Specifically, the air outlet 32 has a circular shape in accordance with the outer shape of the impeller 20. The air outlet 32 is formed such that a predetermined gap is formed between the air blower 32 and the ring portion 28 of the impeller 20 so that the impeller 20 can rotate therein.

  In the shroud 30 of this embodiment, the shapes of the air inlet 31 and the air outlet 32 are different. For this reason, the shroud 30 includes a wide portion and a narrow portion between the peripheral edges of the air inlet 31 and the air outlet 32. That is, in the shroud 30, the distance between the peripheral edges of the air inlet 31 and the air outlet 32 varies depending on the circumferential position around the axis SC of the rotating shaft 11.

  In the present embodiment, the air inlet 31 has a rectangular shape in which the dimension in the vehicle width direction DR2 is longer than the dimension in the vehicle vertical direction DR1. For this reason, in the shroud 30 of the present embodiment, among the peripheral edges of the air inlet 31 and the air outlet 32, the vicinity of the center in the vehicle left-right direction DR2 is the peripheral edges of the air inlet 31 and the air outlet 32. The narrow portion 30b has a small interval.

  In the axial blower 1 configured as described above, as shown in FIG. 1, in the ventilation path 30 a of the shroud 30, the lateral air flow is dominant as indicated by the broken-line arrow ARair. For this reason, in the narrow part 30b of the shroud 30, vortices are likely to occur due to the collision of the lateral air flows as indicated by the broken arrow ARair. For this reason, the axial blower 1 of the present embodiment has a configuration in which vortices are likely to occur particularly near the outer peripheral side end of the impeller 20 as compared with the one without the narrow portion 30b.

  Next, details of the blade 24 of the impeller 20 of the present embodiment will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, the blade 24 is formed with an auxiliary wing portion 25 at the outer peripheral side end portion of the front edge portion 24a.

  Further, in the blade 24 of the present embodiment, a serrated serration portion 26 is formed on the inner peripheral side of the auxiliary wing portion 25 in the front edge portion 24a in order to suppress separation of the airflow on the surface of the blade 24. The serration portion 26 includes a plurality of triangular projections 261 that generate vertical vortices. The plurality of protrusions 261 are formed so as to be aligned in the direction in which the front edge 24a extends.

  The auxiliary wing portion 25 is connected to the ring portion 28 at the outer peripheral portion. Further, the auxiliary wing part 25 has an auxiliary front edge part 251 extending from the root part 25 a intersecting with the front edge part 24 a to the virtual circumferential line VCL, that is, the tip part 25 b intersecting with the ring part 28. The auxiliary front edge portion 251 is a portion on the inner peripheral side of the auxiliary wing portion 25.

  In the auxiliary wing portion 25 of the present embodiment, one side of the protrusion 261 located on the outermost peripheral side of the front edge 24a and the auxiliary front edge 251 among the plurality of protrusions 261 constituting the serration portion 26 are V-shaped. It is provided in the front edge part 24a so that a recessed part may be formed.

  The auxiliary front edge portion 251 of the present embodiment is a protrusion whose angle θα formed with the circumferential line CL centering on the axis SC of the rotary shaft 11 passing through the root portion 25a is located on the outermost peripheral side of the front edge portion 24a. It is set to have a size equivalent to an angle θβ formed by one side of the portion 261 and the circumferential line CL. The difference between the angle θα formed between the auxiliary front edge 251 and the circumferential line CL and the angle θβ formed between one side of the projection 261 located on the outermost peripheral side of the front edge 24a and the circumferential line CL is, for example, , And is set to fall within a range of about ± 5 °.

  Further, as shown in FIG. 5, the auxiliary front edge 251 of the present embodiment has a virtual circumferential line VCL, that is, a part of the auxiliary front edge 251 compared to a virtual straight line VSL that partially connects the root part 25 a and the tip part 25 b. The shape is bent so as to be close to the ring portion 28.

  Specifically, the auxiliary front edge portion 251 of the present embodiment has a shape in which an intermediate portion between the root portion 25 a and the tip portion 25 b is depressed toward the virtual circumferential line VCL, that is, the ring portion 28.

  The auxiliary front edge portion 251 of the present embodiment has a shape in which a portion recessed toward the ring portion 28 is curved in an arc shape. In addition, the recessed part in the auxiliary | assistant front edge part 251 may be the shape which combined the some straight line, ie, the bent shape, for example. Moreover, the recessed part in the auxiliary | assistant front edge part 251 is not restricted to the intermediate part of the root part 25a and the front-end | tip part 25b, For example, you may provide in the front-end | tip part 25b vicinity or the root part 25a vicinity.

  Furthermore, the auxiliary wing portion 25 of the present embodiment is formed in a region TR surrounded by the virtual straight line VSL and the virtual circumferential line VCL. Thereby, as for the auxiliary wing | blade part 25 of this embodiment, the surface area of a wing surface is smaller than the surface area of the wing surface of the auxiliary wing | blade part which has an auxiliary | assistant front edge part in alignment with the virtual circumference line VCL.

  Next, the operation of the axial blower 1 of the present embodiment will be described. In the axial blower 1, the impeller 20 rotates as the rotating shaft 11 of the electric motor 10 rotates. Thereby, as shown in FIG. 2, the air sucked into the impeller 20 from the radiator 2 side is blown out along the axis SC of the rotating shaft 11.

  Here, FIG. 6 is a schematic front view of the blade B of the axial-flow fan CE of the comparative example. The axial blower CE of the comparative example is different from the axial blower 1 of the present embodiment in that the auxiliary blade portion Bs provided on the blade B is simply triangular. That is, in the axial blower CE of the comparative example, the auxiliary front edge Bsf of the auxiliary wing Bs provided on the blade B extends along a virtual straight line VSL that linearly connects the root portion 25a and the tip portion 25b. For convenience of explanation, in FIG. 6, the same reference numerals are assigned to the same configurations as those of the axial flow fan 1 of the present embodiment in the axial flow fan CE of the comparative example.

  In the axial blower CE of the comparative example, the air sucked into the impeller 20 from the radiator 2 side is blown out along the axis SC of the rotary shaft 11 by the rotation of the impeller 20. At this time, in the vicinity of the end on the outer peripheral side of the blade B, a vortex VR is generated by an airflow or the like that flows backward from the blowing side of the impeller 20 to the suction side. When the vortex VR collides with the auxiliary front edge Bsf of the auxiliary wing Bs provided on the blade B, periodic pressure fluctuations that cause noise are increased due to interference between the vortex VR and the blade B. In particular, as in the comparative example axial fan CE, when the auxiliary wing Bs provided on the blade B is simply triangular, the vortex VR is formed on the auxiliary front edge Bsf of the auxiliary wing Bs provided on the blade B. Since it becomes easy to collide, the periodic sound made unpleasant in hearing will become large. The periodic sound is called so-called BPF (abbreviation of Blade Passing Frequency) noise.

  On the other hand, in the axial blower 1 of the present embodiment, a part of the auxiliary front edge portion 251 of the auxiliary wing portion 25 is closer to the ring portion 28 than the virtual straight line VSL as shown in FIG. It has a bent shape. For this reason, in the axial blower 1 of this embodiment, the area which collides with the vortex VR generated in the vicinity of the outer peripheral side end of the blade 24 in the auxiliary wing portion 25 is small, and the impact at the time of collision between the vortex VR and the auxiliary wing portion 25 Is alleviated. Thereby, in the axial blower 1 of this embodiment, the pressure fluctuation | variation used as the generation | occurrence | production factor of BPF noise can be suppressed.

  Here, FIG. 7 is a measurement result of SPL (abbreviation of Sound Pressure Level) which is a sound pressure level when the impeller 20 is rotated in the axial blower 1 of the present embodiment and the axial blower CE of the comparative example. It is drawing which shows. In FIG. 7, the measurement result in the range of the predetermined rotation angle in the impeller 20 is shown. In FIG. 7, the SPL measurement result of the axial blower 1 of the present embodiment is indicated by a solid line A, and the SPL measurement result of the centrifugal blower CE of the comparative example is indicated by a broken line B.

  According to the measurement results shown in FIG. 7, the axial blower 1 of the present embodiment has an SPL amplitude Am1 that is smaller than the SPL amplitude Am2 of the axial blower CE of the comparative example, and causes of BPF noise generation. It can be seen that the pressure fluctuation can be suppressed.

  8 shows the O.D. when the impeller 20 is rotated with respect to the axial fan CE of the comparative example in the axial fan 1 of the present embodiment. A. The amount of decrease in SPL (abbreviation of “Over All”) and the amount of decrease in SPL for each order component of rotation are shown. In FIG. 8, the rotation first order component is displayed as BPF first order, the rotation second order component as BPF second order, and the rotation first order component as BPF third order. O. A. Is the sum of products of SPLs of all frequencies.

  As shown in FIG. 8, the axial blower 1 of the present embodiment is an SPL O.D. A. Is smaller than the SPL of the axial blower CE of the comparative example, and it can be seen that the noise reduction effect is obtained as a whole. Moreover, in the axial-flow fan 1 of this embodiment, it turns out that the reduction effect of the BPF primary noise and the BPF tertiary noise is large.

  The axial blower 1 of the present embodiment described above has a shape in which a part of the auxiliary front edge portion 251 of the auxiliary wing portion 25 is bent so as to be closer to the ring portion 28 than the virtual straight line VSL. . Thus, if the shape of the auxiliary front edge portion 251 is a shape bent so as to be close to the virtual circumferential line VCL connecting the outer peripheral side ends of the plurality of blades 24, the outer peripheral side end portions of the plural blades 24 The interference between the vortex and the auxiliary front edge 251 can be suppressed. Thereby, since the pressure fluctuation of the air in the outer peripheral side of the some braid | blade 24 is suppressed, it becomes possible to aim at reduction of the noise of the axial blower 1 at the time of rotation of the impeller 20. FIG.

  Moreover, the axial-flow fan 1 of this embodiment is formed in the area | region TR where the auxiliary wing | blade part 25 is enclosed by the virtual circumference line VCL and the virtual straight line VSL. With such a configuration, as compared with a configuration in which the auxiliary front edge Bsf extends along the virtual straight line VSL as in the comparative example, interference with vortices generated at the outer peripheral side ends of the plurality of blades 24 in the auxiliary wing portion 25 occurs. The area to be performed can be reduced. Thereby, the pressure fluctuation of the air in the outer peripheral side of the some braid | blade 24 can fully be suppressed.

  Furthermore, the axial blower 1 of the present embodiment is provided with a plurality of triangular projections 261 that generate vertical vortices on the front edge 24 a of the blade 24. And the auxiliary wing | blade part 25 is set so that one side of the protrusion part 261 and the auxiliary | assistant front edge part 251 which are located in the outermost peripheral side of the front edge part 24a among the several protrusion parts 261 may form a V-shaped recessed part. It is provided on the front edge 24a.

  According to this, separation of the airflow on the surface of the blade 24 can be suppressed by the vertical vortex generated by the plurality of protrusions 261 provided on the front edge portion 24a. In particular, the auxiliary wing 25 is provided on the front edge 24a so that one side of the protrusion 261 located on the outermost peripheral side of the front edge 24a and the auxiliary front edge 251 form a V-shaped recess. In this case, the auxiliary front edge 251 can function as a vertical vortex generating means. Thereby, since the separation of the airflow on the surface of the auxiliary blade portion 25 can be suppressed, the noise in the axial flow fan 1 can be further reduced.

  Furthermore, in the axial blower 1 of the present embodiment, the impeller 20 has an annular ring portion 28 that extends along the virtual circumferential line VCL. The auxiliary wing portions 25 of the plurality of blades 24 are connected to the ring portion 28. In this way, if the annular ring portion 28 is used to connect the auxiliary blade portions 25 of the plurality of blades 24, it is possible to sufficiently ensure the strength of the auxiliary blade portions 25 of the plurality of blades 24.

  Here, in the configuration in which the narrow portion 30b in which the distance between the peripheral edges of the air inlet 31 and the air outlet 32 is small with respect to the shroud 30 is provided, a vortex is likely to occur in the vicinity of the outer peripheral end of the impeller 20. . For this reason, as in the present embodiment, the axial blower 1 capable of suppressing the interference between the vortex generated at the outer peripheral side end portions of the plurality of blades 24 and the auxiliary front edge portion 251 is provided with the narrow portion 30b in the shroud 30. This is suitable for the configuration described above.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. 9 and FIG. In the present embodiment, an example in which the shape of the auxiliary front edge portion 251A of the auxiliary wing portion 25 of the blade 24 is changed with respect to the first embodiment will be described.

  As shown in FIG. 9, the auxiliary front edge portion 251A of the present embodiment has a virtual circumferential line VCL, that is, a ring portion 28, as compared with a virtual straight line VSL that linearly connects the root portion 25a and the tip portion 25b. The shape is bent so that The auxiliary front edge 251A of the present embodiment has an angle formed by a reference tangent TLr at a position intersecting the auxiliary wing 25 on the virtual circumferential line VCL and a tangent TL at the auxiliary front edge 251, that is, a tangent angle θt. The root part 25a side is smaller than the root part 25a side.

  Specifically, the auxiliary front edge 251 of the present embodiment has a shape obtained by combining two straight lines, that is, a bent shape. That is, the auxiliary front edge portion 251 of the present embodiment is configured by a portion extending linearly from the root portion 25a toward the root portion 25a and a portion extending linearly from the root portion 25a toward the root portion 25a.

  Further, in the auxiliary front edge portion 251 of the present embodiment, the tangent angle θt1 formed between the tangent TL1 and the reference tangent TLr at the root portion 25a side is formed between the tangent TL2 and the reference tangent TLr at the root portion 25a side. It is smaller than the tangent angle θt2.

  As a result, the auxiliary front edge 251 of the present embodiment is a position where the distal end portion 25b has advanced in the rotational direction from the intersection IP of the tangent line TL2 and the virtual circumferential line VCL in the portion on the root portion 25a side. .

  Other configurations are the same as those of the first embodiment. In the axial blower 1 of the present embodiment, the same effects as those of the first embodiment can be obtained with respect to the configuration common to the first embodiment.

  In particular, in the axial blower 1 of the present embodiment, the tangent angle θt1 of the portion on the root portion 25a side of the auxiliary front edge 251 is smaller than the tangent angle θt2 of the portion on the root portion 25a side.

  According to this, the area | region which interferes with the vortex produced in the outer peripheral side edge part of the some braid | blade 24 in the front-end | tip part 25b side in the auxiliary wing | blade part 25 becomes smaller than the root part 25a side. That is, the auxiliary wing portion 25 has an area that interferes with vortices generated at the outer peripheral side end portions of the plurality of blades 24 decreases on the distal end portion 25b side and gradually expands toward the root portion 25a side. According to this, since the impact generated when the vortex generated at the outer peripheral end portions of the plurality of blades 24 collides with the auxiliary wing portion 25 is further mitigated, the air pressure fluctuation on the outer peripheral side of the plurality of blades 24 is sufficiently reduced. Can be suppressed.

  Here, FIG. 10 shows an O.D. for the axial fan CE of the comparative example in the axial fan 1 of the present embodiment. A. The amount of decrease in SPL and the amount of decrease in SPL for each order component of rotation are shown. FIG. 10 corresponds to FIG. 8 described above.

  As shown in FIG. 10, the axial blower 1 of the present embodiment is an SPL O.D. A. Is smaller than the SPL of the axial blower CE of the comparative example, and it can be seen that the noise reduction effect is obtained as a whole. Moreover, in the axial-flow fan 1 of this embodiment, the noise reduction effect of BPF primary-BPF tertiary each becomes large, and the noise reduction effect can be expected rather than the axial-flow fan 1 of 1st Embodiment. .

(Modification of the second embodiment)
In the second embodiment described above, an example in which the auxiliary front edge 251 has a shape formed by combining two straight lines has been described, but the present invention is not limited to this. For example, as shown in FIG. 11, the auxiliary front edge portion 251A may be curved in an arc shape. Although not shown, the auxiliary front edge 251A may have a shape in which three or more straight lines are combined. Also in the auxiliary front edge portion 251A having these shapes, the same effects as those of the second embodiment can be obtained.

(Other embodiments)
As mentioned above, although embodiment of this invention was described, the axial-flow fan 1 of this invention is not limited to the above-mentioned embodiment, For example, it can deform | transform variously as follows.

  As in each of the above-described embodiments, the impeller 20 of the axial blower 1 is desirably provided with the serration portions 26 for the plurality of blades 24. However, the configuration is not limited thereto, and the configuration may be such that the serration portions 26 are not provided. .

  As in each of the above-described embodiments, the impeller 20 of the axial blower 1 is preferably configured to connect the outer peripheral sides of the plurality of blades 24 with the ring portion 28, but is not limited to this, It is good also as a structure which does not connect an outer peripheral side with the ring part 28. FIG.

  The axial blower 1 described in the above embodiments is suitable for a configuration in which the narrow portion 30b is provided in the shroud 30, but is applicable to a configuration in which the narrow portion 30b is not provided in the shroud 30.

  In each of the above-described embodiments, the example in which the blade 24 of the impeller 20 is configured by the trailing edge blade has been described. However, the present invention is not limited thereto, and for example, the blade 24 of the impeller 20 is configured by the forward blade or the straight blade. May be.

  In each of the above-described embodiments, the example in which the axial blower 1 is applied to a device that supplies air to a radiator 2 such as a radiator mounted on a vehicle has been described. The present invention can also be applied to an air supply device in an air conditioner or a ventilator. The axial blower 1 is applicable not only to an air conditioner but also to various devices.

  In the above-described embodiment, it is needless to say that elements constituting the embodiment are not necessarily indispensable except for the case where it is clearly indicated that the element is essential and the case where it is considered that it is clearly essential in principle.

  In the above-described embodiment, when numerical values such as the number, numerical value, quantity, range, etc. of the constituent elements of the embodiment are mentioned, it is particularly limited to a specific number when clearly indicated as essential and in principle. Except in some cases, the number is not limited.

  In the above embodiment, when referring to the shape, positional relationship, etc. of the component, etc., the shape, positional relationship, etc. unless otherwise specified and in principle limited to a specific shape, positional relationship, etc. It is not limited to etc.

(Summary)
According to the first aspect shown in part or all of the above-described embodiments, the axial blower has a plurality of auxiliary front edge portions of the auxiliary wing portions provided on the front edge portions of the plurality of blades. It has a bent shape so as to be close to a virtual circumferential line connecting the outer peripheral side ends of the blade.

  Moreover, according to the 2nd viewpoint, the axial-flow fan is formed in the area | region where an auxiliary wing | blade part is enclosed by a virtual circumferential line and a virtual straight line. Thus, if it is set as the structure which forms an auxiliary wing part in the area | region enclosed by a virtual circumference and a virtual straight line, compared with the auxiliary wing part where an auxiliary front edge part extends along a virtual straight line, in an auxiliary wing part It is possible to reduce a region that interferes with the vortex generated at the outer peripheral side ends of the plurality of blades. Thereby, the pressure fluctuation of the air in the outer peripheral side of a some braid | blade can fully be suppressed.

  Further, according to the third aspect, in the axial blower, the auxiliary front edge portion has a tangent angle on the tip portion side smaller than a tangential angle on the root portion side. The tangent angle is an angle formed by a tangent at a position intersecting the auxiliary wing portion on the virtual circumferential line and a tangent at the auxiliary front edge.

  According to this, since the region that interferes with the vortex generated at the outer peripheral end of the plurality of blades on the tip portion side in the auxiliary wing portion is smaller than the root portion side, air pressure fluctuation on the outer peripheral side of the plurality of blades is reduced. It can be suppressed sufficiently.

  According to the fourth aspect, the axial blower is provided with a plurality of triangular protrusions that generate vertical vortices at the front edge. The auxiliary wing portion is provided at the front edge portion so that one side of the protrusion portion located on the outermost peripheral side of the front edge portion and the auxiliary front edge portion forms a V-shaped recess among the plurality of protrusion portions. It has been.

  According to this, separation of the airflow on the surface of the blade can be suppressed by the vertical vortex generated by the plurality of protrusions provided on the front edge. In particular, if the front wing is provided with an auxiliary wing so that one side of the protrusion located on the outermost peripheral side of the front edge and the auxiliary front edge form a V-shaped recess, the auxiliary front edge The portion can function as a vertical vortex generating means. Thereby, since separation of the airflow on the surface of the auxiliary wing portion can be suppressed, it is possible to further reduce the noise in the axial fan.

  Moreover, according to the 5th viewpoint, an axial-flow fan is equipped with the shroud in which the air blowing port which blows off the air from the air introducing port which introduces air, and an air introducing port was formed. The shroud is provided with a narrow portion in which the distance between the peripheral edges of the air inlet and the air outlet is small in the circumferential direction of the rotating shaft. In this way, in the configuration in which the narrow portion where the distance between the peripheral edges of the air inlet and the air outlet is small is provided for the shroud, vortices are likely to occur near the outer peripheral side end of the impeller. For this reason, the axial blower capable of suppressing the interference between the vortex generated at the outer peripheral end portions of the plurality of blades and the auxiliary front edge portion is suitable for the configuration in which the shroud is provided with a narrow portion.

  Moreover, according to the 6th viewpoint, as for the axial-flow fan, the impeller has the cyclic | annular ring part extended along a virtual circumference. The auxiliary wing portions of the plurality of blades are connected to the ring portion. Thus, if it is set as the structure which connects the auxiliary wing part of a some braid | blade with an annular ring part, it will become possible to ensure the intensity | strength in the auxiliary wing part of a some braid | blade sufficiently.

DESCRIPTION OF SYMBOLS 1 Axial fan 11 Rotating shaft 20 Impeller 24 Blade 24a Front edge part 25, 25 Auxiliary wing part 25a Root part 25b Tip part 251, 251A Auxiliary front edge part

Claims (6)

An axial flow fan that blows air along the axis (SC) of the rotating shaft (11),
A plurality of blades (24) arranged radially with respect to the axis of the rotating shaft, and an impeller (20) for generating an air flow by rotating about the axis of the rotating shaft;
The plurality of blades include a rotation direction of the rotary shaft (at a portion where a circular virtual circumferential line (VCL) connecting outer peripheral side ends of the plurality of blades and a leading edge portion (24a) of the blade intersect ( AR) is advanced to the auxiliary wings (25, 25A),
The auxiliary wing part has auxiliary front edge parts (251, 251A) extending from a root part (25a) intersecting with the front edge part to a tip part (25b) intersecting with the virtual circumferential line,
The auxiliary front edge portion is an axis that is bent so that at least a part thereof is closer to the virtual circumferential line than a virtual straight line (VSL) that linearly connects the root portion and the tip portion. Current blower.   The axial flow blower according to claim 1, wherein the auxiliary wing portion is formed in a region (TR) surrounded by the virtual circumferential line and the virtual straight line. When an angle formed between a tangent line (TLr) at a position intersecting the auxiliary wing portion on the virtual circumferential line and a tangent line (TL) at the auxiliary front edge portion is defined as a tangential angle (θt),
The axial flow fan according to claim 1 or 2, wherein the auxiliary front edge portion has a smaller tangent angle (θt1) on the distal end portion side than the tangential angle (θt2) on the root portion side. The front edge is provided with a plurality of triangular protrusions (261) that generate vertical vortices,
The auxiliary wing portion includes the front edge so that, of the plurality of protrusions, one side of the protrusion located on the outermost peripheral side of the front edge and the auxiliary front edge form a V-shaped recess. The axial blower according to any one of claims 1 to 3, wherein the blower is provided in the section. An air inlet (31) for introducing air, and a shroud (30) formed with an air outlet (32) for blowing out air from the air inlet,
5. The narrow portion (30 b) having a small distance between the peripheral edges of the air inlet and the air outlet is provided in the shroud in the circumferential direction of the rotating shaft. An axial flow blower described in 1. The impeller has an annular ring portion (28) extending along the virtual circumference,
The axial flow blower according to any one of claims 1 to 5, wherein the auxiliary wing portion of each of the plurality of blades is connected to the ring portion.

Images