JP4840343B2 - Cross-flow fan and air conditioner - Google Patents

Description

  The present invention relates to a once-through fan used as a blowing means and an air conditioner equipped with the once-through fan.

Cross-flow fans mounted on conventional air conditioners and the like have been provided with grooves, small depressions, or small protrusions along the rotation direction around the periphery of the suction side surface of each blade (for example, (See Patent Document 1).
In addition, a notch-shaped groove is intermittently provided at the tip of the outer peripheral side of each blade at intervals in the longitudinal direction of each blade. Some cross-flow fans have a thickness greater than the thickness (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 3-210093 (pages 2 and 3, FIG. 1) JP-A-3-249400 (pages 2 and 3, FIG. 1)

  In the once-through fan disclosed in Patent Document 1, it is assumed that a high-bandwidth noise is generated in the discharge part, and pressure fluctuations that occur when the flow passing through the blade approaches the trailing edge and peels off are Or it is trying to suppress broadband noise by absorbing by forming small depressions or small protrusions. However, when the once-through fan makes one revolution, the flow direction of the flow through the blades is reversed reversely between the impeller suction side and the blowout side. On the impeller suction side, separation occurs at the leading edge of the blade. When the grooves, small depressions, and small projections become the leading edge with respect to the flow, that is, when the blade is located on the impeller suction side, a large flow velocity difference in the longitudinal direction of the blade due to the concentration of the flow in the small groove portion or On the other hand, the flow separation at the side of the small depression and the instability due to the generation of the flow in the longitudinal direction of the blade by the small protrusions cause pressure fluctuations and worsen the broadband noise. Further, when the ventilation resistance increases due to dust adhesion to the filter disposed on the impeller suction side, the air flow becomes unstable due to a change in the angle of attack of the flow with respect to the blade, and the blowout flow becomes unstable. Furthermore, if the discharge flow becomes unstable and a reverse flow from the outlet side to the cross-flow fan occurs, condensation occurs on the impeller during cooling operation, etc., and condensed water is discharged to the outside, and an air conditioner is installed. Indoor floors may get wet.

  Further, in the once-through fan disclosed in Patent Document 2, a groove portion in which a blade is notched is formed in the blade tip portion on the outer peripheral side of the impeller, and separation fluctuations and rotation noise are generated by minute fluctuation flow and vortex generated in the groove portion. And broadband noise reduction. Usually, the once-through fan has a stabilizer that separates the impeller suction region and the blowout region and defines the position of the circulating vortex generated inside the impeller. In the configuration having the notched groove portion, when the impeller rotates and the blade passes through the stabilizer, the leakage flow in the groove portion increases. That is, in the groove provided at the tip of the blade outer peripheral side, the leakage flow from the impeller outlet side having a high total pressure to the impeller suction side having a low total pressure is larger than that in the portion having no groove at the tip of the blade. . Further, in the impeller outlet side region, a leakage flow occurs from the blade pressure surface to the suction surface at the groove portion, and the loss increases. As a result, the motor torque required for the same amount of air flow increases, and the power consumption increases. This is particularly noticeable when dust is attached to the filter and the ventilation resistance is high.

  Also, if the corners facing the blade tip of the notch, which is a groove, have a sharp shape, and the wind vane is removed from the air conditioner outlet, the hand can easily reach the cross-flow fan. Problems arise. For example, if the cross-flow fan is touched with a wing to clean it with a rag or cloth, the rag or cloth may get caught at the corners, causing the cloth to tear or even injure the finger.

  In addition, when a thermoplastic resin containing glass fibers is used as the material for the impeller of the cross-flow fan to ensure the strength of the blades, fine irregularities are generated on the impeller surface by the glass fibers. Fine dust that could not be removed by the filter 5 or the electrostatic precipitator 6 adheres to the uneven portion of the impeller surface, which may cause mold or absorb odors in the room. . Conventionally, as a countermeasure, a mold prevention material is sometimes kneaded and molded into a thermoplastic resin, which is a material of an impeller, but since a minute unevenness remains on the blade surface, it has not been completely countered. In particular, when the wing surface has uneven surfaces such as steps, notches, and protrusions, fine dust is easily caught at the corners, and dust and dust further adhere to the wing tip and wing surface with this as the core, Furthermore, mold was easy to occur. So, if you insert a hand from the air conditioner outlet and clean the dust attached to the blades with a rag, etc., the outer surface of the cross-flow fan impeller blade outer peripheral surface and the blade suction surface can be wiped off. As the finger did not reach the tip of the blade's inner periphery and the blade's pressure surface, it could not be cleaned sufficiently, so dust remained.

The present invention has been made in order to solve the above-described problems. It is an object of the present invention to obtain a cross-flow fan that can reduce wide-band noise and rotational noise, is low-noise, and can stabilize operation against changes in ventilation resistance. Objective.
Furthermore, it aims at obtaining a quiet and high-quality air conditioner by installing a once-through fan with quiet operation noise.

  A cross-flow fan according to the present invention includes at least two disc-shaped support plates arranged at predetermined intervals, a shaft that passes through the center of the support plate and serves as a rotation shaft, and both ends of the support plate are outer peripheral portions of the support plate. A plurality of blades that are arc-shaped between the blade outer peripheral side end and the blade inner peripheral side end in a cross section perpendicular to the rotation shaft and extending in the direction of the rotation axis, and with respect to the rotation direction of the blade A recess extending in the direction of the rotation axis provided at at least one end of the blade outer peripheral side end and the blade inner peripheral side end of the blade suction surface serving as a rear surface, and the recess includes the end portion It is characterized by a step shape extending obliquely so that the distance along the blade suction surface from the tip of the blade gradually increases or decreases.

  The cross-flow fan according to the present invention includes at least two disc-shaped support plates arranged at a predetermined interval, a shaft that passes through the center of the support plate and serves as a rotation axis, and both ends of the support plate. A plurality of blades that are fixed to the outer periphery and extend in the direction of the rotation axis, and are arc-shaped between the blade outer peripheral end and the blade inner peripheral end in a cross section perpendicular to the rotation axis; and the rotation direction of the blade With respect to the blade suction surface of the blade, the blade outer peripheral side end and the blade inner peripheral side end at least one of the ends, the substantially triangular shape with the tip side of the end as a base or the end And a plurality of groove portions each having a step formed by a substantially trapezoidal concave portion having a lower end at the front end side of the portion and facing the concave side.

  The cross-flow fan according to the present invention includes at least two disc-shaped support plates arranged at a predetermined interval, a shaft that passes through the center of the support plate and serves as a rotation axis, and both ends of the support plate. A plurality of blades that are fixed to the outer periphery and extend in the direction of the rotation axis, and are arc-shaped between the blade outer peripheral end and the blade inner peripheral end in a cross section perpendicular to the rotation axis; and the rotation direction of the blade A plurality of protrusions projecting from the blade suction surface provided in the direction of the rotation axis at the blade outer periphery side end of the blade suction surface serving as a rear surface, and the protrusion includes the blade outer periphery end portion A blade outer peripheral side inclined surface whose height increases from the blade side toward the blade inner peripheral end portion side, and a blade inner portion whose height increases from the blade inner peripheral end portion side toward the blade outer peripheral end portion side The tip of the blade outer peripheral side end portion is centered on the rotation center in a cross section perpendicular to the rotation axis and having a circumferential inclined surface. Provided inside the blade outer periphery circle, and further on the blade suction surface side than the straight line in contact with the blade suction surface in parallel with the chord line connecting the blade outer periphery side end and the blade inner periphery end in the cross section. It is provided.

  Further, the cross-flow fan according to the present invention includes at least two disc-shaped support plates arranged at a predetermined interval, and a plurality of blades whose both ends are fixed to the outer peripheral portion of the support plate and extend in the rotation axis direction. , Wherein the support plate and the blades are made of a thermoplastic resin material containing glass fibers, and a dust adhesion preventive material covering the thermoplastic resin material. It is composed of

  In addition, an air conditioner according to the present invention includes a heat exchanger that uses a cross-flow fan that can reduce noise and is disposed in a suction-side flow path formed by the cross-flow fan and that exchanges heat with the sucked air. It is a thing.

  According to the present invention, the separation vortex is diffused or the surrounding flow is attracted to the blade suction surface by the step, the groove, or the protrusion, thereby suppressing the separation from the blade suction surface and reducing the broadband noise and the rotating sound. In addition, a quiet once-through fan with good hearing and low noise can be obtained.

Further, according to the present invention, a quiet air conditioner with reduced noise can be obtained by mounting a low-noise cross-flow fan.
Hereinafter, specific embodiments will be described with reference to the drawings. However, Embodiments 1 and 3 show embodiments to which the present invention is applied, and Embodiments 2, 4, and 5 show embodiments that are reference examples.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing an air conditioner equipped with a cross-flow fan 8 according to the present embodiment, and FIG. 2 is a longitudinal sectional view taken along line MM in FIG. In FIG.1 and FIG.2, the air conditioner main body 1 is installed in the wall of the room air-conditioned. The air conditioner main body upper portion 1a is provided with a suction grill 2 that serves as a suction port for room air, an electric dust collector 6 that electrostatically collects dust and collects dust, and a mesh-like filter 5 that removes dust. Furthermore, the heat exchanger 7 having a configuration in which the pipe 7b passes through the plurality of aluminum fins 7a is arranged on the front side and the upper side of the impeller 8a so as to surround the impeller 8. Moreover, the air conditioner main body front surface 1b is covered with the front panel, and the blower outlet 3 is opened on the lower side. The cross-flow fan 8 which is a blower has a stabilizer 9 for temporarily storing water droplets dripped from the heat exchanger 7 while separating the suction-side flow path and the blow-off-side flow path from the impeller 8a, and the impeller 8a. The blowout side has a spiral guide wall 10 for constituting the back side of the blowout side flow path. Further, an up / down wind direction vane 4a and a left / right wind direction vane 4b are rotatably attached to the air outlet 3 to change the blowing direction into the room. In the figure, O indicates the rotation center of the impeller 8a, C1 is a suction region of the impeller 8a, and C2 is a blowout region of the impeller 8a. RO indicates the rotation direction of the impeller 8a.

  FIG. 3 is a schematic view showing the impeller 8a of the cross-flow fan 8 according to the present embodiment, FIG. 3 (a) is a side view of the cross-flow fan 8, and FIG. 3 (b) is N- in FIG. N-line sectional view is shown, the lower half shows a state in which a plurality of wings on the other side can be seen, and the upper half shows one wing 8c.

  In FIG. 3, the impeller 8a of the once-through fan 8 has a plurality of impellers 8d in the rotation axis direction AX. The impeller unit 8d includes at least two disc-shaped support plates arranged at a predetermined interval, for example, a ring 8b, and a plurality of ends that are fixed to the outer periphery of the ring 8b and extend in the rotation axis direction AX. It is comprised with the wing | blade 8c. The impeller single unit 8d is formed of a thermoplastic resin such as AS resin or ABS resin, for example, and is connected to the rotation axis direction AX by welding or the like to form the impeller 8a. The fan shaft 8f is fixed to the center of the ring 8b at one end, and the fan boss 8e and the motor shaft 12a of the motor 12 are fixed to the center of the ring 8b at the other end with screws or the like. In the cross section perpendicular to the rotational axis of the impeller 8a, the blade 8c includes a blade outer peripheral end near the blade outer peripheral tip 13a and a blade inner peripheral end near the blade inner peripheral tip 13b. The center line of one blade forms a curve that leans forward in the rotational direction RO at the blade outer peripheral end near the blade outer peripheral tip 13a. When the motor 12 rotates about the motor shaft 12a as the rotation center, the impeller 8a rotates in the RO direction and is blown. Here, the blade outer peripheral tip 13a indicates a portion including the tip of the blade outer peripheral end and the vicinity thereof, and the blade inner peripheral tip 13b includes the tip of the blade inner peripheral end and the vicinity thereof. Indicates the part. Further, the blade outer peripheral side end portion indicates a portion including the blade outer peripheral side tip portion 13a from the blade central portion, and the blade inner peripheral side end portion indicates a portion including the blade inner peripheral side tip portion 13a from the blade central portion.

  At least one end of the blade outer peripheral side end and the blade inner peripheral side end of the blade 8c is provided with a step-shaped recess extending in the rotation axis direction AX, and the configuration of the step 11 will be described in detail with reference to FIG. explain. FIG. 4 is an explanatory view showing a blade 8c according to the present embodiment. FIG. 4 (a) shows a blade suction surface 13d as a rear surface with respect to the rotation direction RO of the blade 8c, and FIG. It is the VV sectional view taken on the line 4 (a). When the blade 8c rotates in the RO direction, the front surface becomes the blade pressure surface 13c and the rear surface becomes the blade negative pressure surface 13d with respect to the rotation direction RO of the blade 8c.

  The step 11 provided, for example, at the blade outer peripheral end of the blade suction surface 13d is concave on the blade outer peripheral tip 13a side, from the tip of the blade outer peripheral tip 13a to the step leading edge 11a or the step trailing edge 11b. This is a shape that extends obliquely so that the distance along the blade suction surface 13d gradually increases or decreases. In the figure, Ha is a line parallel to the blade outer peripheral tip portion 13a and passes through the step leading edge portion 11a closest to the blade outer peripheral tip portion 13a, and Hb is a line parallel to the blade outer peripheral tip portion 13a. , A line passing through the step trailing edge 11b closest to the blade outer circumferential tip 13a. That is, the step leading edge 11a and the step trailing edge 11b are parallel, but both extend in a direction having an oblique angle with respect to the blade outer circumferential tip 13a. The blade thickness of the concave portion from the tip of the blade outer peripheral side tip portion 13a to the step trailing edge portion 11b is thinner than the blade thickness of the blade center portion.

  In the air conditioner body 1 configured in this way, when the motor 12 is energized from the power supply board, the impeller 8a of the cross-flow fan 8 rotates in the RO direction. Then, the air in the room is sucked in from the suction port 2 provided in the upper part 1a of the main body, dust is removed by the electric dust collector 6 and the filter 5, and then the air is heated and heated or cooled by the heat exchanger 7 to be cooled. The dehumidification is performed, and the air is sucked into the impeller 8a of the cross-flow fan 8. After that, the airflow blown out from the impeller 8a is guided to the guide wall 10 and directed to the blowout port 3, and is blown into the room from the blowout port 3 to be air conditioned. At this time, by controlling the direction of the blown air in the vertical and horizontal directions by the vertical wind direction vanes 4a and the horizontal wind direction vanes 4b, wind is caused to flow through the entire room to suppress temperature unevenness.

Here, it is assumed that the blade 8c is in the suction region C1. As the impeller 8a rotates in the RO direction, the air flow E0 flows to the blade suction surface 13d, and separation tends to occur at a portion where the blade shape of the blade outer peripheral end is bent. In the present embodiment, the step 11 provided obliquely at this portion causes the distance from the tip end portion 13a of the peeling blade to be slightly shifted in the rotation axis direction AX. For this reason, a rotation sound can be reduced because the generation | occurrence | production phase of peeling vortex changes and is spread | diffused.
Further, when the blade 8c is in the blowing area C2, the airflow flows in the direction opposite to E0 in FIG. The same is true in this case, and the flow tends to be separated at a portion where the blade shape at the blade outer peripheral end is bent, but the phase at which the flow separates from the blade 8c is slightly shifted in the rotation axis direction AX. For this reason, the phase from which the flow separates is changed and diffused, and noise can be reduced.

  FIG. 5 is an explanatory view showing another configuration example of the blade 8c according to the present embodiment, and shows a blade negative pressure surface 13d which is a rear surface with respect to the rotation direction RO of the blade 8c. The cross section of the wing 8c is the same as that shown in FIG. In this configuration example, a plurality of, for example, two steps 11a and 11b are formed in the blade suction surface 13d in the rotation axis direction AX. The two steps 11a and 11b have different angles with respect to the blade outer peripheral side tip portion 13a, and connect the two steps 11 near the center. For this reason, the two steps 11a and 11b are configured such that the concave sides face each other at the central portion in the rotation axis direction AX. Similar to the step 11 in FIG. 4, the step 11 provided obliquely shifts the separation position and the separation position little by little in the rotation axis direction AX. For this reason, the generation phase of the separation vortex and separation changes and is diffused, so that the rotational sound can be reduced and the noise can be reduced. Furthermore, by arranging the concave sides of the two steps 11 so as to face each other, in the suction region C1, the air flow is collected at the central portion of the impeller unit 8d, while the vortex over the step 11 is the end of the impeller unit 8d, That is, it has a direction component toward the ring 8b. For this reason, it can suppress that an air current peels from the blade negative pressure surface 13d, and can reduce broadband noise.

  FIG. 6 is an explanatory diagram showing still another configuration example of the blade 8c according to the present embodiment, and shows a blade suction surface 13d that is a rear surface with respect to the rotation direction RO of the blade 8c. The cross section of the wing 8c is the same as that shown in FIG. Also in this configuration example, two steps 11 having different angles with respect to the blade outer peripheral tip portion 13a are formed on the blade suction surface 13d, and the two steps 11 are connected at the central portion. In FIG. 5, the angles of the two steps 11 with respect to the blade outer peripheral tip 13a are reversed. The effect of this configuration is the same as in FIG. In other words, the step 11 provided obliquely shifts the separation position and the position where the flow is separated little by little in the rotation axis direction AX. For this reason, the generation phase of the separation vortex and separation changes and is diffused, so that the rotational sound can be reduced and the noise can be reduced.

  4 to 6, a step 11 is provided on the blade suction surface 13d at the outer peripheral end of the blade to reduce noise. That is, in the suction region C1, the phase of the separation vortex generated at the outer peripheral edge of the blade is changed at the inflow side portion of the air flow into the blade 8c, and conversely in the outlet region C2, the blade is discharged at the outflow side portion from the outer peripheral edge of the blade. Noise is reduced by changing the phase of separation of the flow generated at the outer peripheral end. On the other hand, the step 11 may be provided on the blade negative pressure surface 13d at the blade inner circumferential end on the blade inner circumferential tip 13b side. Since the blade inner peripheral end is an outflow side portion from the blade inner peripheral end in the suction region C1, the step of providing a step changes the separation phase of the flow generated at the blade inner peripheral end. On the other hand, in the blowout region C2, the airflow side portion of the airflow into the blade 8c is conversely provided, so that by providing a step, the phase of the separation vortex generated at the blade inner peripheral end is changed to reduce noise. Good. Further, the step 11 may be provided on both the blade outer pressure side 13d at the blade outer peripheral side end and the blade inner peripheral side end. In this case, noise reduction can be achieved at both the blade inner peripheral end and the blade outer peripheral end at either the suction region C1 or the blowout region C2.

Further, when the step 11 is provided on both the blade suction surface 13d and the blade outer peripheral end and the blade inner peripheral end, the oblique direction between the blade outer tip 13a and the blade outer step, and the blade inner peripheral side It is preferable to provide a step so that the tip portion 13b and the oblique direction between the inner peripheral side step are opposite to each other. FIG. 7 is an explanatory view showing a configuration in which a step 11 is provided at both the blade inner peripheral end and the blade outer peripheral end, and shows the blade negative pressure surface 13d in a plan view. 7A corresponds to the configuration of FIG. 4, FIG. 7B corresponds to the configuration of FIG. 5, and FIG. 7C corresponds to the configuration of FIG. Thus, the step provided on the blade outer peripheral end (outer peripheral step) and the step provided on the blade inner peripheral end (inner peripheral step) are not nearly parallel, but the direction of the rotation axis of the blade 8c. It is better to configure the step 11 to be inclined in the opposite direction so that the steps 11 approach or separate from each other.
If comprised in this way, the distance of an outer peripheral side level | step difference and an inner peripheral side level | step difference differs in the rotating shaft direction AX of the blade | wing 8c. That is, the distance until the flow affected by one step is affected by the other step differs in the rotation axis direction AX. For this reason, it is possible to obtain a greater effect of changing the phase at which the separation vortex is generated at one step 11 and changing the phase at which the flow is separated at the other step 11. Further, even if the outer peripheral side step and the inner peripheral side step are not configured with the same step, noise can be reduced by the step. For example, the outer peripheral side step is shown in FIG. 4, and the inner peripheral step is shown in FIG.

  4 to 6, the step front edge portion 11a and the step rear edge portion 11b are configured to be parallel to each other, but may not be parallel to each other. At least one of the step leading edge 11a and the step trailing edge 11b is not parallel to the blade outer circumferential tip 13a or the blade inner circumferential tip 13b, but may be oblique so as to form a certain angle. If a step is formed obliquely with respect to at least the tip portions 13a and 13b, a certain degree of effect can be expected by shifting the phase in which the flow separation vortex is generated and the phase in which it is separated. As another configuration example, for example, the same applies even if the diagonal in FIG. 4 is reversed. 5 and 6 show the configuration having two steps in the rotation axis direction AX, but more steps may be formed.

  The rising angle in the blade thickness direction of the step 11 constituted by the step leading edge portion 11a and the step trailing edge portion 11b is an angle at which the flow flows along the step 11 at 90 ° (vertical) or less. Is preferred. Further, at the step leading edge portion 11a of the step 11, the blade thickness is thin, but the thickness is such that the strength of the blade 8c can be maintained, and the thickness does not affect the flow when the thermoplastic resin is poured into the mold at the time of molding. You should have it. The blade thickness is thin at the blade outer circumferential tip 13a and the blade inner circumferential tip 13b, and thick at the blade center. For this reason, the step 11 is a portion closer to the blade central portion than the blade outer peripheral tip portion 13a and the blade inner peripheral tip portion 13b, and the blade thickness is thicker than the blade outer peripheral tip portion 13a and the blade inner peripheral tip portion 13b. In this way, the blade thickness at the step leading edge portion 11a can be maintained at the same level as the blade thickness at the blade outer peripheral tip portion 13a and the blade inner peripheral tip portion 13b.

As described above, at least two disc-shaped support plates 8b arranged at a predetermined interval, the shaft 8f passing through the center of the support plate 8b and serving as a rotation axis, and both ends thereof on the outer peripheral portion of the support plate 8b. A plurality of blades 8c that are fixed and extend in the rotational axis direction AX and are arc-shaped between the blade outer peripheral end and the blade inner peripheral end in a cross section perpendicular to the rotational axis, and the rotational direction RO of the blade 8c And a recess extending in the rotation axis direction AX provided at at least one end of the blade outer peripheral side end and the blade inner peripheral end of the blade suction surface 13d as the rear surface, and the recess has a tip 13a at the end. , 13b from the blade suction surface 13d gradually increases or decreases in a step 11 shape that obliquely extends so that separation vortices generated on the blade suction surface 13d and airflow can be separated. Noise can be reduced by shifting the phase in the rotational axis direction AX. There is an effect.
Further, by providing a plurality of steps 11 in the rotation axis direction AX and configuring the at least two adjacent steps 11 so that the concave sides face each other, the separation vortices and airflows that are generated more effectively on the blade suction surface 13d can be separated. There is an effect that noise can be reduced by shifting the phase of the motor in the rotational axis direction AX.

Embodiment 2. FIG.
Hereinafter, a cross-flow fan according to Embodiment 2 of the present invention will be described with reference to the drawings. FIG. 8 is a schematic view showing an impeller 8a of the cross-flow fan 8 according to the present embodiment, FIG. 8 (a) is a side view of the cross-flow fan 8, and FIG. 8 (b) is an H- in FIG. The H line sectional view is shown, the lower half shows a state in which a plurality of wings on the other side are visible, and the upper half shows one wing 8c in detail. 9 is an enlarged perspective view showing one blade of FIG. 8, and FIG. 10 is an explanatory view showing an enlarged part of the blade 8c including a groove formed on the blade suction surface 13d. In the figure, the same reference numerals as those in Embodiment 1 denote the same or corresponding parts.

  In the blade negative pressure surface 13d which is the rear surface with respect to the rotation direction RO of the impeller 8a of the blade 8c, a plurality of grooves in the rotational axis direction AX are provided at at least one of the blade outer peripheral side end and the blade inner peripheral end. 14 was formed. As shown in FIG. 8, the number of the groove portions 14 provided on, for example, the blade outer peripheral end of the blade suction surface 13d is different depending on the length of the impeller single unit 8d in the rotation axis direction. When the distance F2 between the midpoints of the rotation axis direction AX of the plurality of groove portions 14 is substantially the same, for example, when the rotation axis direction length B of the impeller single body 8d is about 75 mm, the blade outer peripheral side tip portion 13a of the groove portion 14 The length A1 of the closest rotation axis direction AX is set to about 5 mm, and F2 is set to about 7 mm.

  Further, as shown on the side surface of the blade 8c in FIG. 9 on the side of the rotation axis, the center line on the side surface of the blade 8c is a curve that is inclined forward in the rotation direction on the outer peripheral side. A straight line connecting the blade outer circumferential tip 13a and the blade inner circumferential tip 13b, which are both ends thereof, is a chord line L, and the position of the blade 8c corresponding to the midpoint of the chord line L is a chord central portion 13e. To do. As shown in FIG. 10, the grooves 14 arranged at a predetermined interval F2 in the rotational axis direction have, for example, a substantially trapezoidal shape when viewed from the front, with the blade outer peripheral tip portion 13a side as the bottom and the blade outer peripheral tip portion 13a side. The groove width A1 in the rotation axis direction AX is gradually reduced from the chord toward the chord center 13e. A groove inner end portion 14a corresponding to the upper base of the substantially trapezoidal groove portion 14 forms a step parallel to the blade outer peripheral tip portion 13a. Moreover, the groove side part 14b forms the diagonal level | step difference with respect to the wing | blade outer periphery front-end | tip part 13a, and a concave side is a shape which faces each other. The inclination θ1 of the facing groove side portion 14b is, for example, about 30 °. In the blade thickness direction, a recess is formed so that the inside of the groove portion 14 is smoothly inclined from the blade outer peripheral tip portion 13a.

  FIG. 11 is a cross-sectional view taken along the line PP in FIG. The surface that is recessed by the groove 14 of the blade suction surface 13d is defined as a groove surface 14c, and the portion where the step between the surface other than the groove of the blade suction surface 13d and the groove surface 14c is the largest is defined as the groove deepest portion A2, and the groove deepest portion. A chord line groove deepest point A2L at the intersection with a straight line perpendicular to the chord line L passing through A2. In the blade cross section, the blade chord line L passes through the center of the inscribed circle indicating the maximum thickness tm among the blade thicknesses t which are the diameters of the circles inscribed in the blade pressure surface 13c and the blade suction surface 13d. The intersecting point with the vertical straight line is the maximum thickness point Tm, and the blade tip side where the groove 14 is formed, here the blade outer peripheral tip 13a side of the blade outer peripheral tip arc center 13ac and the chord line groove deepest point The distance up to A2L is the deepest groove chord distance F1, and the thickness of the blade outer peripheral tip 13a is t1. In the present embodiment, the groove portion 14 is formed so that the blade thickness t in the deepest groove portion A2 is equal to or greater than the thickness t1 of the blade outer peripheral tip portion 13a and equal to or less than the maximum thickness tm.

  In the present embodiment, for example, the radius of the impeller 8a is about 100 mm, the chord length L1 that is the length of the chord line L is about 10 mm, and the wall thickness t1 of the blade outer peripheral tip portion 13a is about 0.5 mm. The wall thickness tm is about 1.1 mm and the deepest groove chord distance F1 is about 2.5 mm.

  In the once-through fan 8, when the blade 8c passes through the impeller suction region C1 on the heat exchanger 7 side, the air flow E0 flows from the blade outer peripheral tip portion 13a to the blade inner peripheral tip portion 13b as shown in FIG. The airflow flowing from the blade outer peripheral tip portion 13a flows to the blade chord center portion 13e directly downstream of the blade inner end portion 14a and flows to the groove side portion 14b and flows to the blade outer peripheral tip portion 13a. Thus, a vortex flow E2 is generated that goes over the step having an oblique angle and wraps around the blade suction surface 13d. Due to the vortex flow E2 generated in the groove side portion 14b, the surrounding flow is attracted to the blade suction surface 13d, and the air flow that is about to separate from the blade suction surface 13d is suppressed. Here, when the groove side portion 14b is parallel to a plane orthogonal to the rotation axis, the flow concentrates on the groove portion, the speed difference becomes large from the place where there is no groove portion, the shear force works, and the flow is disturbed. There is a risk of noise deterioration. On the other hand, in the present embodiment, the groove side portion 14b forms an oblique step having an angle that is neither parallel nor perpendicular to the rotation axis direction of the blade outer peripheral side tip portion 13a, such as the angle θ1. . With this configuration, the vortex flow E2 can be generated, and the surrounding flow is attracted to the blade suction surface 13d, so that separation can be suppressed and generation of broadband noise can be reduced.

  In addition, strong vortices periodically generated on the blade suction surface 13d near the blade outer peripheral tip 13a cause rotation noise. On the other hand, by forming the groove portion 14 at the blade outer peripheral end, irregularities are formed at the blade outer peripheral end, the periodicity of the generated vortex is diffused, and peak rotating sound is reduced.

  On the other hand, when the blade 8c of the cross-flow fan 8 passes through the blowing region C2 of the impeller 8a on the guide wall 10 side, as shown in FIG. 12, the airflow E0 flows from the blade inner peripheral tip portion 13b to the blade outer peripheral tip portion. It flows toward 13a. At this time, in the vicinity of the groove 14 provided at the outer peripheral end portion of the blade, it flows from the chord central portion 13e to the outer peripheral tip portion 13a. The flow E3 from the chord central portion 13e to the groove inner end portion 14a and the flow E4 from the chord central portion 13e to the groove side portion 14b are negative because the groove portion 14 has a concave shape from the upstream chord central portion 13e. Pressure is attracted to the blade suction surface 13d. In this way, separation is suppressed even in the blowing area C2, and the generation of broadband noise can be reduced.

  As described above, by providing the groove portion 14 on the blade suction surface 13d of the blade 8c, separation of both the impeller suction region C1 and the blowout region C2 can be suppressed and broadband noise can be reduced, and the periodicity of the generated vortex can be diffused. And rotating sound can be reduced. In addition, when this cross-flow fan 8 is mounted on an air conditioner, an air curtain, or the like, it usually has a filter 5 on the suction side in order to remove dust in the room, but if dust adheres to the filter 5, ventilation will occur. Resistance increases. When the ventilation resistance increased, the inflow angle to the blade 8c changed, and peeling was likely to occur. In the present embodiment, even when the ventilation resistance is increased in this manner, the vortex flow E2 is generated by the groove portion 14 so that separation can be suppressed to some extent, and broadband noise can be reduced. Further, it is possible to reduce the rotational noise due to the uneven shape of the blade suction surface 13d even in the blowing region. As a result, a quiet air conditioner can be realized.

  Further, the groove portion 14 is formed so that the blade thickness t in the deepest groove portion A2 is equal to or greater than the thickness t1 of the blade outer peripheral side tip and equal to or less than the maximum thickness tm. As a result, the blade thickness t, which is the length in the direction perpendicular to the rotation axis of the blade 8c, does not become thinner than the thickness t1 of the blade outer peripheral tip. For this reason, when the once-through fan 8 is injection-molded, the thermoplastic resin is poured into the mold and molded, but the resin can be poured smoothly without obstructing the hot water around the resin.

  Next, the inclination angle of the groove side portion 14b facing each other in the shape of the groove portion 14 will be described. Here, the groove width A1 in the rotational axis direction AX of the groove side portion 14b is gradually shortened from the blade outer peripheral side tip portion 13a toward the chord center portion 13e, and the angle formed by the groove side portion 14b facing the concave portion is made. Let θ1. The groove side portion 14b constitutes a step which obliquely intersects the straight line extending in the rotation axis direction AX of the blade outer peripheral tip portion 13a, and has an effect of reducing noise as shown in the first embodiment. Furthermore, the noise reduction effect of the groove side part 14b comprised by the angle (theta) 1 which faces is demonstrated here.

  FIG. 13 shows the relationship between the groove side angle θ1, which is the angle formed by both groove side portions 14b of the groove portion 14, and the noise value. In the air conditioner, a groove portion 14 is provided at the blade outer peripheral side end portion of the cross-flow fan, and the noise value is measured in a room near the outlet 3 by changing the angle θ1 of the groove side portion 14b. In FIG. 13, the horizontal axis represents the angle θ1 (°) of the groove side portion 14b, and the vertical axis represents the noise reduction value {dB (A)}. θ1 = 0 ° is a configuration in which the groove portion 14 is not provided, and this is used as a reference noise value, and a reduction value from this noise value is graphed.

  The noise reduction value is greatest when the angle θ1 of the groove side portion 14b is about 30 °, and the noise is not reduced so much when the configuration is smaller than 10 ° and larger than 45 °. When the groove side angle θ1 is smaller than 10 °, the groove side part 14b is close to an angle orthogonal to the rotation axis, and the vortex flow E2 is not generated so much. For this reason, an air current peels and the noise reduction effect is small. That is, it is preferable that the groove side angle θ1 is 10 ° or more because the vortex flow E2 is generated and the airflow can be prevented from being separated to reduce noise.

On the other hand, when the groove side angle θ1 is larger than 45 °, the vortex center of the vortex E2 generated when getting over the groove side part 14b is directed in the direction of the rotation axis and away from the direction of the surrounding flow. For this reason, since the effect which suppresses peeling becomes small, a noise reduction value becomes small. On the other hand, when the groove side angle θ1 is 45 ° or less, the vortex center of the vortex E2 formed when getting over the groove side part 14b is close to the surrounding flow. For this reason, peeling can be suppressed effectively and a big noise reduction value is obtained. Further, when the groove width A1 is widened, the vortex flows E2 generated from the groove side portions 14b of the adjacent groove portions 14 interfere with each other and noise is deteriorated.
That is, it is preferable that the groove side angle θ1 is 45 ° or less, because it is possible to prevent the airflow from being separated by the vortex flow E2 and to reduce noise. However, even if the groove side angle θ1 is larger than 45 °, the interference between the vortex flows E2 at the groove side part 14b of the adjacent groove part 14 is improved to some extent by changing the distance to the adjacent groove part 14 and the like. be able to.

  From the above, in the configuration as shown in FIG. 10, as shown in FIG. 13, it is preferable to configure at 10 ° ≦ groove side angle θ1, which can reduce broadband noise and obtain a quiet cross-flow fan. It is done. Furthermore, it is preferable that the groove side portion angle θ1 ≦ 45 ° is configured, and broadband noise can be reduced, and a quiet cross-flow fan can be obtained.

  Next, in the shape of the groove portion 14, particularly in a cross section perpendicular to the rotation axis of the blade 8 c shown in FIG. 11, the deepest groove blade having a distance from the blade outer peripheral tip arc center 13 ac to the chord line groove deepest point A2L. The chord distance F1 and the ratio F1 / L1 of the length L1 of the chord line L connecting the blade outer peripheral tip portion 13a and the blade inner peripheral tip portion 13b will be described. In FIG. 14, the horizontal axis indicates the ratio F1 / L1 between the deepest groove chord distance F1 and the length L1 of the chord line L, and the vertical axis indicates the noise reduction value {dB (A)}. In the air conditioner, a groove portion 14 is provided at the blade outer peripheral side end portion of the once-through fan, and a noise value is measured in a room near the outlet 3 by changing the groove deepest chord distance F1. F1 / L1 = 0 is a configuration in which the groove portion 14 is not provided, and this is used as a reference noise value, and a reduction value from the noise value is graphed. Here, the groove side portion angle θ1 is 30 °.

  When F1 / L1 is about 0.2, the noise reduction value becomes the largest, and when the configuration is smaller than 0.1 and larger than 0.3, the noise is not reduced so much. If the groove deepest chord distance F1 is large, that is, if F1 / L1 is greater than 0.3, the vortex of the vortex flow E2 develops too much on the chord central portion 13e side of the groove portion 14. Then, the vortex flows by the adjacent groove portions 14 interfere with each other and conversely disturb the surrounding flow, and the noise becomes worse. That is, it is preferable that F1 / L1 is 0.3 or less because ambient air is effectively attracted by the vortex flow E2 generated in the groove side portion 14b, and broadband noise can be reduced. However, even if F1 / L1 is larger than 0.3, it can be improved to some extent by changing the distance between the adjacent groove portions 14 and the like.

  On the other hand, if F1 / L1 is smaller than 0.1, the vortex flow E2 is not sufficiently generated, so that there is no effect. For this reason, it is preferable that F1 / L1 is 0.1 or more because the vortex flow E2 can be sufficiently generated to reduce noise.

  From the above, it is preferable to configure with 0.1 ≦ F1 / L1, and it is possible to reduce broadband noise and obtain a quiet once-through fan. Further, it is preferable that F1 / L1 ≦ 0.3, and the vortex of the vortex flow does not develop too much on the chord center portion 13e side of the adjacent groove portion 14, and the vortex flow E2 generated on the groove side portion 14b Since the attraction of ambient air does not interfere, broadband noise can be reduced, and a quiet cross-flow fan can be obtained.

  Next, in the shape of the groove portion 14, particularly in the impeller unit 8 d excluding both axial ends of the impeller 8 a shown in FIG. 8, the distance between the blade length B between the adjacent rings 8 b and the midpoint in the rotation axis direction of the groove portion 14. The ratio F2 / B of the distance F2 will be described. FIG. 15 shows the ratio F2 / B between the groove center point distance F2 and the inter-ring blade length B on the horizontal axis, and the noise reduction value {dB (A)} on the vertical axis. This is because, in the air conditioner, a groove portion 14 is provided at the blade outer peripheral side end of the once-through fan, and a groove center-to-groove distance F2 that is an interval between the adjacent grooves 14 is changed, so that the noise value in the room near the outlet 3 is increased. Is measured. F2 / B = 0 is a configuration in which the groove portion 14 is not provided, and this is used as a reference noise value, and a reduction value from this noise value is graphed. Here, the groove side angle θ1 was 30 °, and F1 / L was 0.2.

  When F2 / B is about 0.2, the noise reduction value is the largest, and when the configuration is smaller than 0.1 and larger than 0.3, the noise is not reduced so much. When the groove deepest chord distance F2 is small, that is, when F2 / B is smaller than 0.1, the number of the groove portions 14 formed at the distance B increases, and the distance between the adjacent groove portions 14 becomes close, and the rotation axis direction It is necessary to shorten the groove side portion 14b. For this reason, the vortex flow E2 cannot be sufficiently generated, and a sufficient low noise effect cannot be obtained. Therefore, it is preferable that F2 / B is 0.1 or more, because the vortex flow E2 can be sufficiently generated at the groove side portion 14b, and broadband noise can be reduced.

  On the other hand, if F2 / B is greater than 0.3, the vortex flow E2 in the adjacent groove side portion 14b is too far away, and the effect of attracting the surrounding flow to the blade suction surface 13d is reduced. Moreover, since the area | region which does not have the groove part 14 increases in the blade | wing negative pressure surface 13d of the blade outer peripheral side front-end | tip part 13a side, peeling in the blade outer peripheral side front-end | tip part 13a arises, and a rotation sound becomes large. Therefore, it is preferable that F2 / B is 0.3 or less because vortex flow E2 can be sufficiently generated, separation can be reduced, rotational noise can be reduced, and broadband noise can be reduced. However, even if F2 / B is greater than 0.3, it can be improved to some extent by changing the axial length A1 of the groove 14 and the groove side angle θ1.

  In view of the above, it is preferable that 0.1 ≦ F2 / B be configured, a rotating sound is small, broadband noise can be reduced, and a quiet once-through fan with good audibility can be obtained. Furthermore, it is preferable that F2 / B ≦ 0.3, and it is possible to obtain a quiet once-through fan with a low rotational noise, reduced wide-band noise, and good audibility.

  FIG. 16 is a perspective view showing one blade 8c of cross-flow fan 8 according to the present embodiment as another configuration example of groove 14. As shown in FIG. 16, a plurality of groove portions 14 provided on the blade outer peripheral side end portion side of the blade negative pressure surface 13 d are provided adjacent to each other without leaving a gap with the adjacent groove portion 14. As in the configuration example of FIG. 9, the shape of the groove portion 14 is a substantially trapezoidal shape with the blade outer peripheral tip portion 13a side as the bottom, and gradually rotates from the blade outer peripheral tip portion 13a toward the chord center portion 13e. A groove side portion 14b having a groove width A1 in the direction AX is reduced. Between adjacent groove portions 14, a blade negative pressure surface 13 d that protrudes in a substantially triangular shape on the blade outer peripheral side tip portion 13 a side is formed.

  Thus, by forming so that the bottom bottom of the groove part 14 may adjoin, the protrusion part formed of the groove side parts 14b of the adjacent groove part 14 becomes a triangular shape with a sharp tip. For this reason, when the impeller 8a passes through the suction region C1 at the groove inner end portion 14a, it is possible to generate a strong vortex flow E2 that crosses the slanted groove side portion 14b and goes around the blade surface. As the vortex flow E2 becomes stronger, the surrounding flow is more easily attracted to the blade suction surface 13d, and the surrounding flow is suppressed. Therefore, peeling is suppressed and broadband noise can be reduced. Further, the flow flowing in from the blade outer peripheral tip portion 13a side is collected inside the groove portion 14, and the boundary layer that is supposed to be formed inside the groove portion 14 is caused to flow out of the groove portion 14 by the momentum of the flow. For this reason, it becomes difficult to develop the boundary layer in the blade outer peripheral side end, and further, peeling can be suppressed.

  In addition, in the blowing region C2, strong vortices generated on the blade suction surface 13d at the blade outer peripheral end cause rotation noise. In the configuration of the groove portion 14 as shown in FIG. 16, similar to the configuration of FIG. 9, the periodicity is diffused and the peak rotational noise is reduced by the uneven shape formed by the groove portion 14 at the blade outer peripheral side end portion.

  In addition, although the groove part 14 demonstrated based on FIG.9 and FIG.16 was provided in the blade outer peripheral side edge part, it is not restricted to this, You may provide in a blade inner peripheral side edge part. Moreover, when the groove part 14 is formed in both the outer peripheral side edge part and inner peripheral side edge part of the blade | wing 8c, each flow phenomenon in the impeller suction area | region C1 and the blowing area | region C2 arises in one blade. Furthermore, noise can be reduced.

  9 and 16, the groove portion 14 has been described as a substantially trapezoidal concave portion with the tip end side of the end portion of the blade outer periphery side tip portion 13a or the blade inner periphery side tip portion 13b as a bottom, but is not limited thereto. It is not a thing. For example, the same effect can be obtained even when the wing outer peripheral tip portion 13a and the wing inner peripheral tip portion 13b are configured by a substantially triangular recess having the bottom side as a base.

  As described above, in the present embodiment, at least two disc-shaped support plates 8b arranged at a predetermined interval, the shaft 12a passing through the center of the support plate 8b and serving as a rotation axis, and both ends are supported. A plurality of blades 8c fixed to the outer peripheral portion of the plate 8b and extending in the rotation axis direction AX and having an arc shape between the blade outer peripheral end and the blade inner peripheral end in a cross section perpendicular to the rotation axis; Is provided at at least one of the blade outer peripheral side end and the blade inner peripheral side end of the blade negative pressure surface 13d which is the rear surface with respect to the rotational direction of the blade, and the tip 13a, 13b side of the end is a base. It is provided with a plurality of grooves 14 having a stepped portion 14b that is formed of a triangular shape or a substantially trapezoidal concave portion with the tip 13a, 13b side of the end as the bottom, and facing the concave side, thereby suppressing flow separation. Therefore, a low noise cross-flow fan can be obtained.

Further, the angle θ1 formed by the facing step 14b is set to 10 ° or more, and the distance A1 between the facing steps 14b is widened at the end portions 13a and 13b, so that the separation of the flow can be effectively suppressed and low noise can be achieved. Can be obtained.
Further, by setting the angle θ1 formed by the step 14b facing each other to be 45 ° or less, it is possible to effectively suppress the separation of the flow and obtain a low-noise cross-flow fan.

  Further, in a cross section perpendicular to the rotation axis of the blade 8c, a straight line connecting the tip 13a of the blade outer peripheral end and the tip 13b of the blade inner peripheral end is defined as a chord line L, and the groove 14 is surrounded by the inside of the groove 14. The portion where the step is formed is the groove deepest portion A2, and the intersection with the straight line passing through the groove deepest portion A2 and perpendicular to the chord line L is the chord line groove deepest point A2L. The distance from the arc center of the arcuate tip to the chord line groove deepest point A2L is the deepest groove chord distance F1, the chord line L is the chord length L1, and the deepest chord distance F1. By configuring the ratio of the chord length L1 to be 0.1 ≦ F1 / L1 ≦ 0.3, flow separation can be effectively suppressed, and a low-noise cross-flow fan can be obtained.

  The length of the blade 8c in the rotation axis direction AX is the blade length B, the plurality of grooves 14 are arranged at substantially equal intervals in the rotation axis direction AX, and the ratio of the groove interval F2 to the blade length B is 0.1 ≦ F2. By configuring so that /B≦0.3, separation of the flow can be effectively suppressed, and a low-noise cross-flow fan can be obtained.

Embodiment 3 FIG.
Hereinafter, a cross-flow fan according to Embodiment 3 of the present invention will be described with reference to the drawings. FIG. 17 is an enlarged perspective view showing one blade 8c of the cross-flow fan 8 according to the present embodiment. FIG. 18 is an explanatory diagram showing an enlarged part of the blade negative pressure surface 13d when the impeller 8a is mounted on an air conditioner and the blade 8c is positioned in the suction region C1, and FIG. It is explanatory drawing which expands and shows a part of blade | wing negative pressure surface 13d at the time of being located in the blowing area | region C2 in an air conditioner. The main configuration in the present embodiment is the same as that in the first and second embodiments, and the same reference numerals indicate the same or corresponding parts, and the description thereof is omitted here.

  A blade 8c shown in FIG. 17 has a configuration in which the groove portion 14 shown in FIG. 16 in the second embodiment is provided and a notch portion 15 is further provided in each groove portion 14. The notch 15 is provided at at least one end of the blade inner peripheral end and the blade outer peripheral end of the blade 8c, and is cut out from the tip 13a, 13b of the end toward the inside of the blade 8c. And a plurality of them are arranged in the rotation axis direction AX. In particular, in the present embodiment, notches 15 are provided in all of the recesses formed by the plurality of grooves 14, and the notches 15 are respectively positioned at the centers of the recesses formed by the grooves 14.

  As shown in FIG. 18, the notch 15 provided in the vicinity of the midpoint of the groove width A1 in the rotation axis direction AX opens, for example, in a substantially triangular shape, and the base of the triangular shape is the tip of the blade outer peripheral side that is the blade tip. It faces the part 13a. The corners of the cutout corner 15a corresponding to both ends of the bottom side and the blade pressure surface 13c and the blade suction surface 13d of the cutout side 15b corresponding to the two sides of the triangle are formed in a rounded arc shape. ing.

When the blade 8c passes through the suction region C1, the air flow E0 flows from the direction of the arrow. At this time, the vortex flow E2 that crosses the groove-side portion 14b that is slanted with respect to the blade outer peripheral tip portion 13a and circulates to the blade surface is strongly generated, and the surrounding flow is easily attracted to the blade negative pressure surface 13d. For this reason, the surrounding flow is suppressed and the airflow is prevented from being separated from the blade suction surface 13d.
Furthermore, it is well known that strong separation vortices generated on the blade outer peripheral tip 13a and the blade outer peripheral tip 13a side of the suction surface 13d cause rotation noise. By providing the notch 15, the separation vortex is diffused. That is, a vortex is generated by the notch 15 from the blade pressure surface 13c toward the blade suction surface 13d, and this vortex flows along the blade suction surface 13d. This vortex attracts the flow on the blade suction surface 13d and is restrained by the blade suction surface 13d. For this reason, the separation vortex is diffused. Furthermore, the periodicity of the separation vortex is diffused by the oblique step formed by the groove 14. For this reason, a rotation sound is reduced.

  Further, as shown in FIG. 19, when the blade 8c passes through the blowing region C2, the air flow E0 flows from the arrow direction. At this time, the flow E3 from the chord central portion 13e to the groove inner end portion 14a and the flow E4 to the groove side portion 14b are attracted by the groove portion 14 having a concave shape from the upstream chord central portion 13e and becoming negative pressure. Peeling is suppressed. The action of the notch 15 at this time is the same as that of the suction region, and the minute fluctuation flow and vortices generated in the notch 15 relieve the separation and further reduce the rotational noise and broadband noise.

Further, in the case where only the notch portion 15 is formed without the groove portion 14 at the blade outer peripheral tip portion 13a, a leakage flow is generated at the notch portion 15 and the loss is increased. On the other hand, since the groove portion 14 is provided in the present embodiment, the leakage flow from the blade pressure surface 13 c to the blade negative pressure surface 13 d in the notch portion 15 is suppressed by the flow passing through the groove portion 14. For this reason, the loss caused by the leakage flow can be reduced, and the power consumption can be reduced. In particular, the effect of reducing power consumption is great when dust adheres to the filter 5 and the ventilation resistance increases.
Thus, by combining the groove 14 and the notch 15, it is possible to prevent a decrease in air output due to a reduction in the blade area, which was a problem in the case of the configuration of only the notch 15, and synergizes the noise reduction effect of both. Can demonstrate.

Further, in the present embodiment, the cutout corner 15a and the cutout side 15b are formed in an arc shape with rounded corners. For example, when dust adheres to the impeller 8a and the wing outer peripheral side tip 3a of the impeller 8a is wiped directly with a rag or the like, the rag can be cut off or the finger can be prevented from being injured even if wiped in the direction of the rotation axis. A cross-flow fan is obtained.
In this way, even if the ventilation resistance increases, rotating noise is suppressed and broadband noise is reduced, resulting in a low-noise, good audibility, energy saving, and a good quality once-through fan that ensures safety during cleaning. It is done.

In the present embodiment, the configuration example in which the groove portion 14 and the notch portion 15 are provided in the blade outer peripheral side tip portion 13a has been described, but may be provided in the blade inner peripheral side tip portion 13b. Further, if the blade is provided at both the blade outer peripheral tip portion 13a and the blade inner peripheral tip portion 13b, an even greater noise reduction effect can be obtained.
Moreover, although the notch part 15 is provided in the inside of all the groove parts 14, it is not restricted to this, There may be a part which does not provide the notch part 15, and there exists a certain amount of effect. However, if it arrange | positions so that it may become line symmetrical with respect to the line which passes along the center of the rotating shaft direction of the impeller 8a, the cross-flow fan with which the airflow was stabilized is obtained.
Here, the notch 15 is further provided in the groove 14 having the configuration shown in FIG. 16, but the notch is further added to the configuration having the step 11 having the configuration shown in FIGS. 4, 5, and 6 in the first embodiment. 15 may be provided. Further, a notch portion 15 may be further provided in the configuration having the groove portion 14 shown in FIG. 9 in the second embodiment. Providing the step 11 or the groove 14 and the notch 15 has an effect of further reducing noise.

As described above, according to the present embodiment, the blade 8c is provided at at least one end of the blade inner peripheral end and the blade outer peripheral end, and from the tip 13a, 13b of the end to the inside of the blade 8c. By providing a plurality of cutout portions 15 in the direction of the rotation axis AX, rotational noise and broadband noise can be reduced, and a quiet cross-flow fan can be obtained.
Moreover, since the corner | angular part of the front-end | tip 15a of the notch part 15 was rounded, it can maintain cleanly by becoming easy to clean, and a safe once-through fan is obtained.

Embodiment 4 FIG.
Hereinafter, a cross-flow fan according to Embodiment 4 of the present invention will be described with reference to the drawings. FIG. 20 is a perspective view showing one blade 8c of the impeller 8a according to the present embodiment. FIG. 21 is an explanatory diagram showing an enlarged part of the blade negative pressure surface 13d when the impeller 8a is mounted on an air conditioner and the blade 8c is positioned in the suction region C1, and FIG. It is explanatory drawing which expands and shows a part of blade | wing negative pressure surface 13d at the time of being located in the blowing area | region C2 in an air conditioner. 23 is a cross-sectional view taken along the line QQ in FIG. 21, and FIG. 24 is a cross-sectional view taken along the line RR in FIG. Note that the main configuration in this embodiment is the same as that in Embodiment 1 or Embodiment 2, and the same reference numerals indicate the same or corresponding parts, and description thereof is omitted here.

  As shown in FIGS. 20 and 21, in the blade suction surface 13d that is the rear surface with respect to the rotational direction RO of the impeller 8a, the blade outer peripheral end projects from the blade suction surface 13d toward the blade chord center portion 13e. It has the projection part 16 to do. As shown in an enlarged view in FIG. 21, a plurality of, for example, three protrusions 16 are provided between the rings 8b in the rotation axis direction AX at a predetermined interval G1. The bottom surface of one protrusion 16 in contact with the blade suction surface 13d is a polygon that is short in the rotation axis direction AX and long in the rotation direction RO, and is a front blade outer peripheral inclined surface 16a and a rear blade in the rotation direction RO. It has a peripheral inclined surface 16b, two side surfaces 16c along the rotation direction RO, and a protruding upper surface 16d.

  The blade outer peripheral inclined surface 16a is an inclined surface whose height increases from the blade outer peripheral end portion side toward the blade inner peripheral end portion side, and the blade inner peripheral inclined surface 16b is formed from the blade inner peripheral end portion side. It is a blade inner peripheral side inclined surface whose height increases toward the blade outer peripheral end side. In addition, in the blade cross section perpendicular to the rotation axis shown in FIG. 23, the protrusion 16 does not protrude outwardly beyond the blade outer circle D passing through the blade outer peripheral tip 13a with the rotation center O as the center. Further, the shape protrudes from the blade suction surface 13d. The straight line Ls is parallel to the chord line L that connects the arc center 13ac of the blade outer circumferential tip 13a and the arc center 13bc of the blade inner circumferential tip 13b and does not protrude from the straight line Ls that contacts the blade suction surface 13d. Rather than the blade suction surface 13d side.

  Further, as shown in FIG. 24, the two side surfaces 16c of the protrusion 16 along the rotation direction RO are formed with inclined surfaces that are tapered toward the inside of the protrusion 16 as they are separated from the blade negative pressure surface 13d. An angle formed by both inclined surfaces is defined as an inclination angle θ2. Further, the corner 16e of the protrusion 16 is rounded.

  In the cross-flow fan 8 formed in this way, as shown in FIG. 21, when the blade 8c is located in the suction region C1, the airflow E0 rotates from the blade outer peripheral end 13a toward the blade inner peripheral end 13b. The direction is opposite to the direction RO. For this reason, the airflow E0 flows from the blade outer peripheral side end portion 13a to the blade negative pressure surface 13d, and flows to the blade outer peripheral side inclined surface 16a of the protrusion 16. The blade outer peripheral inclined surface 16a is an inclined surface whose height from the blade negative pressure surface 13d gradually increases from the blade outer peripheral tip portion 13a side toward the chord central portion 13e side. Therefore, the airflow tends to flow downstream while climbing on the blade outer peripheral inclined surface 16a, and as shown in FIGS. 21 and 24, the vertical vortex E5 along the side surface 16c is generated, and downstream along the side surface 16c. It will flow. At this time, ambient air is attracted by the vertical vortex E5, and airflow is prevented from being separated from the blade suction surface 13d. By suppressing the separation of the airflow, the rotational noise of the cross-flow fan can be reduced.

  Here, the vertical vortex refers to a vortex that forms a surface perpendicular to the blade suction surface 13d, and the horizontal vortex refers to a vortex that forms a surface parallel to the blade suction surface 13d. If the blade outer peripheral inclined surface 16a is configured to stand upright on the blade negative pressure surface 13d, an air current strikes the blade outer peripheral inclined surface 16a and tends to flow in the lateral direction, so that a horizontal vortex is generated. However, when a horizontal vortex is formed, a wake vortex is generated in the vicinity of the blade inner peripheral inclined surface 16b, which adversely affects the airflow. By generating the vertical vortex E5 by the protrusion 16, the airflow can be prevented from being separated from the blade suction surface 13d.

  On the other hand, as shown in FIG. 22, when the blade 8c is located in the blowing region C2, the airflow E0 is directed from the blade inner peripheral tip portion 13b to the blade outer peripheral tip portion 13a and in the same direction as the rotational direction RO. At this time, the airflow E0 flows from the blade inner peripheral side tip 13b to the blade suction surface 13d, and the boundary layer starts to develop from the point where it exceeds the chord central portion 13e. The protrusion 16 is located on the downstream side of the chord central portion 13e, and the blade inner peripheral inclined surface 16b of the protrusion 16 gradually moves from the chord central portion 13e side toward the blade outer peripheral end portion 13a side. The inclined surface increases in height from the negative pressure surface 13d. For this reason, the flow that develops the boundary layer that has flowed beyond the chord central portion 13e tends to flow downstream while climbing on the blade inner circumferential inclined surface 16b, and a vertical vortex E6 is generated along the side surface 16c. It flows downstream along the side surface 16c. The vertical vortex E6 diffuses the separation vortex generated in the surrounding area to suppress the separation and reduce broadband noise.

  Further, as described based on FIG. 23, in the cross section perpendicular to the rotation axis, the protrusion 16 is centered on the rotation center O and does not protrude from the blade outer periphery circle D in contact with the blade outer peripheral side tip portion 13a. The shape is such that it fits inside the blade outer periphery circle D. For this reason, since the projection part 16 does not protrude outside from the locus | trajectory by rotation of the impeller 8a, it can prevent that the projection part 16 disturbs the flow outside the impeller 8a. Here, if the blade outer peripheral inclined surface 16a is formed so as to substantially coincide with the circumference of the blade outer periphery circle D, the vertical vortex E5 can be generated smoothly with respect to the airflow flowing in the suction region C1.

  Furthermore, the length of the protrusion 16 in the rotation direction RO is longer than the length in the rotation axis direction AX. For this reason, in both the impeller suction region C1 and the blowout region C2, the flow on the blade suction surface 13d is forced to flow in the rotational direction RO by the adjacent protrusions 16. That is, the flow is rectified and stabilized by the protrusion 16.

  Further, in the present embodiment, in the direction of the impeller rotation axis between the rings 8b, one protrusion 16 is disposed at the center position, and two protrusions 16 are disposed at the center so as to be line symmetric. In this way, if the protrusions 16 are arranged in line symmetry in the impeller single unit 8d, the flow can be symmetrical, so that the flow is stabilized. As a result, the flow is stabilized by the once-through fan 8, and even if ventilation resistance is added to the filter 5, the air can be stably blown.

  Further, the side surface 16c is a tapered inclined surface inclined inward of the protrusion 16, and the inclination angle θ2 between the side surfaces 16c is set to 10 ° ≦ θ2 ≦ 90 °, for example. That is, the angle from the surface perpendicular to the blade suction surface 13d on one side surface 16c is θ2 / 2, which is about 5 ° to 45 °. If this angle is too small, the side surface 16c rises to be nearly vertical, and the vertical vortices E5 and E6 generated on the blade outer peripheral side inclined surface 16a and the blade inner peripheral side inclined surface 16b cannot flow smoothly downstream. Further, if this angle is too large, the height of the protrusion 16 is lowered, and the vertical vortices E5 and E6 cannot be sufficiently generated on the blade outer peripheral side inclined surface 16a and the blade inner peripheral side inclined surface 16b, and peeling occurs. Cannot be sufficiently suppressed.

  In addition, since the corner 16e of the protrusion 16 is formed in a rounded curved surface, the airflow flows smoothly and can be kept clean and secure safety during cleaning. For example, when the blade 8c is wiped with a cloth such as a rag in the impeller rotation axis direction AX, the cloth can be smoothly slid to the side surface 16c through the rounded upper surface 16d from the side surface 16c. You can also clean the root area. Furthermore, since the corner portion 16e is not sharp, there is no worry of being caught and injured, which is safe.

  In addition, the shape of the protrusion part 16 is not restricted to this embodiment. For example, the upper surface 16d may not be flat but may be round like a part of a substantially spherical surface. Further, the blade outer peripheral side inclined surface 16a, the blade inner peripheral side inclined surface 16b, and the two side surfaces 16c are not limited to planes, respectively, and may be rounded inclined surfaces, or may be formed by inclined surfaces having some corners. It may be. For example, a conical shape whose bottom surface shape is an ellipse long in the rotational direction RO, or two side surfaces 16c along the rotational direction RO are semicircular, and the side surface 16c is composed of the blade outer peripheral inclined surface 16a and the blade inner peripheral inclined surface 16b. The shape which cut | disconnected the cylinder vertically etc. which comprise the surface which connects can be sufficient.

  Further, in the blade cross-sectional view of FIG. 23, the protrusion 16 may be configured so as to be located on the blade suction surface 13d side with respect to the straight line Ls and on the blade suction surface 13d side with respect to the blade outer circumference circle D. May be longer. Further, the length in the rotation axis direction AX may be shorter. However, if the angle between the side surface 16c and the surface perpendicular to the blade suction surface 13d is set to a certain degree, for example, an angle of 5 ° or more, the longitudinal vortices E5 and E6 can be generated, and the same effect as described above can be obtained. Further, the number of the protrusions 16 is not limited to the present embodiment, and may be two or four or more in the rotation axis direction AX.

  The protrusion 16 may be manufactured as an integral part when the wing 8c is injection-molded, or may be manufactured by fixing the separately formed protrusion 16 to the wing 8c.

  As described above, according to the present embodiment, at least two disc-shaped support plates 8b arranged at a predetermined interval, the shaft 12a that passes through the center of the support plate 8b and serves as a rotation axis, and both ends Is fixed to the outer peripheral portion of the support plate 8b and extends in the rotational axis direction AX, and a plurality of blades 8c having an arc shape between the blade outer peripheral end and the blade inner peripheral end in a cross section perpendicular to the rotational axis; A plurality of protrusions 16 projecting from the blade suction surface 13d provided in the rotation axis direction AX at the blade outer peripheral side end portion of the blade suction surface 13d as a rear surface with respect to the rotation direction RO of the blade 8c. The blade outer peripheral side inclined surface 16a whose height increases from the blade outer peripheral end portion side toward the blade inner peripheral end portion side, and the height from the blade inner peripheral end portion side toward the blade outer peripheral end side. The blade outer peripheral side inclined surface 16b is increased, and the blade outer periphery is centered on the rotation center O in a cross section perpendicular to the rotation axis. The blade suction surface is provided on the inner side of the blade outer periphery circle D passing through the tip 13a of the end, and is parallel to the chord line L connecting the tip 13a of the blade outer peripheral end and the tip 13b of the blade inner peripheral end in cross section. By providing the blade suction surface 13d side with respect to the straight line Ls in contact with 13d, a cross-flow fan that can reduce rotational noise and broadband noise is obtained.

  Furthermore, the flow of the airflow can be rectified by the protrusions 16, and the reduction of the blowing efficiency can be suppressed even if the ventilation resistance increases due to clogging of the filter or the like.

  Further, the side surface 16c along the rotation direction RO of the protrusion 16 is formed by an inclined surface that inclines toward the inner side of the protrusion 16 as it moves away from the blade suction surface 13d, so that a vertical vortex can be generated. And a once-through fan capable of reducing broadband noise.

  Further, since the corner portion 16e of the projection portion 16 is configured to be round, the corner portion of the uneven surface of the projection portion 16 becomes slippery, so that dust is not easily caught and the cross-flow fan can be kept clean. In addition, it is possible to obtain a cross-flow fan that can be safely cleaned and can maintain hygiene.

Embodiment 5 FIG.
Hereinafter, a cross-flow fan according to Embodiment 5 of the present invention will be described with reference to the drawings. FIG. 25 is an enlarged perspective view showing one blade 8c of the impeller 8a according to the present embodiment. FIG. 26 is an explanatory diagram showing an enlarged part of the blade suction surface 13d when the impeller 8a is mounted on an air conditioner and the blade 8c is positioned in the suction region C1, and FIG. It is explanatory drawing which expands and shows a part of blade | wing negative pressure surface 13d at the time of the blade | wing 8c being located in the blowing area | region C2. FIG. 28 is a cross-sectional view taken along line TT in FIG. 26, and FIG. 29 is a cross-sectional view taken along line SS in FIG. In addition, about the main structure in this Embodiment, it is the same as that of Embodiment 1-Embodiment 4, the same code | symbol shows the same or an equivalent part, and abbreviate | omits description here.

As shown in the drawing, in the blade suction surface 13d which is the rear surface with respect to the rotation direction RO of the impeller, the blade outer surface side end of the blade 8c protrudes from the blade suction surface 13d, and the length of the rotation direction RO is the rotation axis. The protrusion 16 having a bottom shape longer than the length in the direction AX is provided. A plurality of, for example, three protrusions 16 are arranged at a predetermined interval G1 in the rotation axis direction AX by one impeller 8d. The configuration of the protrusion 16 is the same as that of the fourth embodiment.
Further, a groove 14 is provided in the vicinity of the protrusion 16. The groove portion 14 has the same configuration as that of the groove portion 14 in the second embodiment, but since the protrusion 16 is formed on the blade outer peripheral side tip portion 13a side, the central portion of the chord is more than in the configuration of the second embodiment. It is provided at a position shifted toward 13e. The groove portion 14 provided on the blade negative pressure surface 13d is disposed at a predetermined distance from the projection portion 16, and is provided in a substantially U shape so as to surround at least a part of the blade inner peripheral inclined surface 16b. The side on which the protrusion 16 is provided is defined as a recess.

  Hereinafter, the substantially U-shaped groove portion 14 will be described in detail. The groove portion 14 has a substantially U shape having a groove inner end portion 14a and a groove side portion 14b. The groove side portion 14b has an angle with respect to the rotation axis direction AX, and forms a step extending toward the tip 13a side of the blade outer peripheral end, and the two opposing groove side portions 14b are the blade inner peripheral tip. The width A1, which is the distance in the rotational axis direction AX, gradually increases from the portion 13b side toward the blade outer peripheral side tip portion 13a side. As shown in the figure, the inclination of the groove side portion 14b is a predetermined angle θ3 with respect to a plane orthogonal to the impeller rotation axis. This angle θ3 is formed to be substantially the same as the angle θ1 in the second embodiment or slightly wider than the angle θ1 because the protrusion 16 is provided.

Further, the groove inner end portion 14a is a step which faces the blade inner peripheral side inclined surface 16b of the projection portion 16 and extends in the rotation axis direction AX. The groove side portion 14b is connected to both ends of the step of the groove inner end portion 14a. Further, a groove connection step 14d extending in the rotation axis direction AX is formed between the adjacent protrusions 16, and the adjacent groove portions 14 are connected by the groove connection step 14d. The blade connection step 14d is located closer to the blade outer circumferential tip 13a than the position where the blade inner circumferential inclined surface 16b of the protrusion 16 intersects the blade negative pressure surface 13d. That is, the rising portion on the blade negative pressure surface 13d of the blade inner peripheral inclined surface 16b is surrounded by the groove inner end portion 14a and the groove side portion 14b. In the present embodiment, at least a part of the blade inner peripheral inclined surface 16b of all the protrusions 16 is surrounded by the groove 14, and the protrusions 16 are arranged on the center line of the groove 14 in the width A1 direction.
Further, as shown in FIG. 28, the two side surfaces 16c along the rotation direction RO of the protrusion 16 are tapered inclined surfaces that incline toward the inside of the protrusion 16 as the distance from the blade negative pressure surface 13d increases. Is θ2, and the corner 16e of the protrusion 16 is formed as a round curved surface.

  In the impeller 8a of the cross-flow fan 8 formed in this way, as shown in FIG. 26, when the blade 8c is located in the suction region C1, the airflow E0 is changed from the blade outer peripheral tip portion 13a to the blade inner peripheral tip portion 13b. In the direction opposite to the rotational direction RO. For this reason, as described in the fourth embodiment, the vertical vortex E5 is generated along the side surface 16c of the protrusion 16, and flows downstream along the side surface 16c. At this time, the ambient air is attracted to the vertical vortex E5, and the airflow is prevented from separating from the blade suction surface 13d, so that the rotational noise can be reduced.

  Furthermore, a groove side portion 14b is formed in the vicinity of the blade inner peripheral side inclined surface 16b of the projection portion 16. As in the second embodiment, the vortex flow E2 is generated at the step of the groove side portion 14b and the surrounding air is attracted, so that separation is suppressed. Further, the step of the facing groove side portion 14b has a shape such that the groove width A1 becomes narrower toward the chord center portion 13e side and surrounds the blade inner circumferential inclined surface 16b. Thereby, the generation of the wake vortex on the blade inner peripheral inclined surface 16b can be suppressed to further suppress the turbulent flow, and the vertical vortex E5 generated along the side surface 16c can be effectively acted. That is, the effect of attracting ambient air by the vertical vortex E5 is further obtained, and the broadband noise can be greatly reduced.

  On the other hand, as shown in FIG. 27, when the blade 8c is located in the blowing region C2, the airflow flows from the blade inner peripheral tip portion 13b to the blade outer peripheral tip portion 13a, and is in the same direction as the rotational direction RO. At this time, the blade inner peripheral inclined surface 16b of the protrusion 16 is located downstream of the chord central portion 13e, and gradually decreases from the blade chord central portion 13e toward the blade outer peripheral tip 13a. It is an inclined surface in which the height of the protrusion 16 from 13d increases. For this reason, the flow generated by the development of the boundary layer flowing from the chord central portion 13e tends to flow downstream while climbing on the blade inner peripheral inclined surface 16b, and the vertical vortex E6 along the side surface 16c is generated to generate the side surface. It flows downstream along 16c. Broadband noise can be reduced by diffusing the separation vortex generated around the vertical vortex E6 to suppress the separation.

  Further, a groove side portion 14b facing at an angle θ3 is formed in the vicinity of the inclined surface 16b on the blade inner peripheral side of the projection portion 16. For this reason, the flow E3 from the chord central portion 13e to the groove inner end portion 14a and the flow E4 to the groove side portion 14b become negative pressure and attracted when the groove portion 14 has a concave shape from the upstream chord central portion 13e. Peeling is suppressed. Further, the vortex flow can be further suppressed by suppressing the wake vortex on the blade outer peripheral side inclined surface 16a of the protrusion 16, and the vertical vortex E6 flowing along the side surface 16c can be effectively applied. That is, since the effect of diffusing the separation by the vertical vortex E6 can be further obtained, the broadband noise can be further reduced.

  Further, as shown in FIG. 28, the side surface 16c of the protrusion 16 is configured, and the side surface 16c is not perpendicular to the blade suction surface 13d. Therefore, when the blade 8c is wiped in the rotation axis direction AX with a cloth such as a rag. Further, the vicinity of the root that intersects the blade suction surface 13d of the side surface 16c can be cleaned, so that it can be kept clean. Furthermore, since the corner portion 16e has a round shape, the cloth does not get caught in the corner portion 16e, and the finger is not injured.

  Hereinafter, the angle θ2 formed by the two opposing side surfaces 16c of the protrusion 16 will be described. FIG. 30 shows the relationship between the angle θ2 formed by the side surface 16c of the protrusion 16 shown in FIG. 28 and the noise level. This is because, in the air conditioner, as shown in FIG. 26, the protrusion 16 and the groove 14 are provided at the blade outer peripheral tip 13a, and the angle θ2 formed by the side surface 16c is changed to measure the noise value in the room near the outlet 3 It is a thing. In FIG. 30, the horizontal axis represents the angle θ2 (°) formed by the side surface 16c, and the vertical axis represents the noise reduction value {dB (A)}. θ1 = 0 ° is a configuration in which the protrusion 16 is not provided, and this is used as a reference noise value, and a reduction value from this noise value is graphed.

  When the side surface angle θ2 is about 20 °, the noise reduction value is the largest, and when the side surface angle θ2 is smaller than 10 ° and larger than 30 °, the noise is not reduced so much. When the side surface angle θ2 is smaller than 10 °, the side surface 16c rises from the blade suction surface 13d at an angle close to perpendicular. In this configuration, the vertical vortices E5 and E6 are not generated well, and the horizontal vortex having the rotation axis in the height direction of the protrusion 16 becomes strong. For this reason, noise will deteriorate due to the large wake of the protrusion 16. That is, when the angle θ2 is 10 ° or more, the vertical vortices E5 and E6 are well generated, and the air currents can be prevented from being separated by the vertical vortices E5 and E6, and the noise can be reduced. Further, as described above, if the side surface angle θ2 is set to 10 ° or more and the rising of the side surface 16c from the blade negative pressure surface 13d is made smooth, cleaning is easy and the rising portion can be kept clean.

  On the other hand, as the side surface angle θ2 becomes larger than 10 °, the angle at which the side surface 16c rises from the blade suction surface 13d becomes gentler. In this case, the airflow flowing through the side surface 16c is the same as the vortex flow E2 in the groove side portion 14b. That is, since the vertical vortices E5 and E6 are not generated well by the protrusion 16, the low noise effect is small. For this reason, when the side surface angle θ2 is set to 30 ° or less, the vertical vortices E5 and E6 are successfully generated on the side surface 16c, and the air current can be prevented from being separated by the vertical vortices E5 and E6, and noise can be reduced.

  From the above, in the configuration shown in FIG. 28, it is preferable that 10 ° ≦ side angle θ2 as shown in FIG. 30, and it is possible to reduce broadband noise and obtain a quiet cross-flow fan. Furthermore, it is preferable that the side surface angle θ2 ≦ 30 ° is configured, and broadband noise can be reduced, and a quiet cross-flow fan can be obtained.

  In the present embodiment, both the effects are further expanded by forming the protrusions 16 and the grooves 14, the rotational sound and the broadband noise generated from the cross-flow fan can be further reduced, easy to clean, audible and quiet, and hygienic. Can maintain a once-through fan.

In the above configuration, the groove 14 surrounding the protrusion 16 is substantially U-shaped, but at least a part of the blade inner peripheral inclined surface 16b of the protrusion 16 is spaced apart from the protrusion 16 by a predetermined distance. What is necessary is just to be comprised so that it may surround. For example, even if the groove portion 14 is formed in a shape such as a substantially V shape, a substantially U shape, or an arc shape, the same effect as described above can be obtained.
Further, in the configuration shown in FIG. 25, all the protrusions 16 are surrounded by the grooves 14, but the present invention is not limited to this. All the protrusions 16 do not have to be surrounded by the groove part 14. For example, when three protrusion parts 16 are provided, the two protrusion parts 16 at both ends may have a groove part shape surrounded by the groove part 14. Conversely, the protrusions 16 do not have to be formed on the blade outer peripheral end portion 13a side of the groove inner end portions 14a of all the groove portions 14.

  In FIG. 25, the groove connection step 14d between the adjacent protrusions 16 is configured as a step parallel to the rotation axis direction AX, but is not limited thereto. FIG. 31 shows a configuration example in which the groove connecting step 14d has the same shape as the groove side portion 14b and the groove inner end portion 14a of the groove portion 14. That is, in the blade negative pressure surface 13d, the groove inner end portion 17a and the groove inner end portion are similar to the groove portion 14 formed by the groove inner end portion 14a and the groove side portion 14b connected to both ends of the groove inner end portion 14a. A groove portion 17 constituted by groove side portions 17b connected to both ends of the portion 17a and facing each other is arranged next to the groove portion.

  In this configuration, in addition to the same effect as that shown in FIGS. 26 and 27, the effect by the groove side portion 17b can be obtained. That is, in the suction area C1 of the impeller 8a, the configuration is the same as that of the groove side portion 14b in FIG. 10, and a vortex flow E2 is generated, and separation at the blade negative pressure surface 13d can be prevented. On the other hand, in the blowing region C2, as in the case of the groove side portion 14b in FIG. 12, peeling can be suppressed by generating negative pressure, and noise can be further reduced as compared with the configuration in FIG.

  Further, instead of configuring the groove connecting step 14d in parallel with the rotation axis direction AX, a configuration may be adopted in which at least a part of the groove connecting step 14d includes a step portion inclined with respect to the rotation axis direction AX. In this case, as shown in the first embodiment, the generation phase of the separation vortex can be changed in the suction region C1 and the phase from which the flow is separated in the blowing region C2 by the groove connection step 14d that is an oblique step. The noise can be reduced.

  Further, in the present embodiment, the configuration in which the groove portion 14 and the projection portion 16 are provided at the blade outer peripheral side end portion is described, but the notch portion 15 described in the fourth embodiment may be further provided. When the notch 15 is provided in at least one blade tip of the blade outer circumferential tip 13a and the blade inner circumferential tip 13b, in addition to the noise reduction effect of the groove 14 and the protrusion 16, the blade negative near the blade tip is further increased. Turbulence on the pressure surface 13d can be reduced, and noise can be reduced. Here, in the case of the protrusion 16, it is effective to provide at the blade outer peripheral end, and in the case of the groove 14 and the notch 15, either the blade outer peripheral end or the blade inner peripheral end. Alternatively, noise reduction effects can be expected even if both are provided.

  As described above, according to the present embodiment, the blade suction surface 13d is disposed at a predetermined distance from the protrusion 16 so as to surround at least a part of the blade inner peripheral inclined surface 16b. By providing the groove portion 14 having a substantially U shape and having the concave portion on the protruding portion 16 side, a longitudinal vortex generated in the protruding portion 16 can be effectively applied to obtain a cross-flow fan capable of reducing broadband noise.

  Further, the groove portion 14 is connected to the step of the groove inner end portion 14a facing the blade inner peripheral inclined surface 16b of the projection portion 16 and extending in the rotation axis direction AX, and to both ends of the step of the groove inner end portion 14a. Due to the step of the groove side portion 14b extending at the tip 13a side of the blade outer peripheral end portion at an angle with respect to the direction AX, the groove inner end portion 14a and the groove side portion 14b generate the protrusion 16 A cross-flow fan that can effectively reduce the broadband noise by using the vertical vortex is obtained.

  In addition, in the cross section of the protrusion 16 perpendicular to the blade suction surface 13d in the rotation axis direction AX, the angle formed by the facing side surfaces 16c is θ2, and 10 ≦ θ2 ≦ 30 °. A strong vortex can be generated, a large wake of the protrusion 16 can be suppressed, and a low-noise cross-flow fan can be obtained.

  In the first to third embodiments and the fifth embodiment, since the step 11 and the groove 14 are formed on the blade suction surface 13d of the blade 8c, the thickness of the blade 8c in the cross section perpendicular to the rotation axis is seen. And it becomes smaller than the thickness of the part in which the level | step difference 11 and the groove part 14 are not provided. Here, as shown in FIG. 11, the overall thickness of the blade 8c is configured such that the thickness of the blade outer peripheral side tip portion 13a is the smallest and the thickness increases toward the blade chord central portion 13e. Therefore, it is preferable to form the step 11 and the groove 14 on the blade suction surface 13d so that the thickness of the blade outer peripheral tip portion 13a is minimized. That is, the step 11 and the groove 14 are formed in a portion thicker than the blade outer peripheral tip portion 13a, and the thickness of the concave portion is set to be equal to or greater than the thickness of the blade outer peripheral tip portion 13a. That's fine. By comprising in this way, a low-noise cross-flow fan can be obtained without obstructing the hot water around the resin during molding.

  In any of the first to fifth embodiments, for example, the blade 8c of the impeller 8a of the cross-flow fan 8 mounted on the air conditioner or the ring 8b that is a support plate is made of glass fiber. It is injection molded with the thermoplastic resin it contains. That is, a thermoplastic resin containing glass fibers is poured into a mold and hardened, and then removed from the mold. In the contact surface between the resin to be injected at the time of molding and the mold, a minute recess is formed on the surface of the wing 8c or the ring 8b that is a molded product. Dust and dust contained in the room air are sucked from the suction port 2 and caught by the filter 5 to be removed. However, dust and dust that have passed through the filter 5 are conditioned by the heat exchanger 7 and enter the once-through fan 8 and flow to the surfaces of the blades 8c and the ring 8b. At this time, if there are minute recesses on the surface of the wing 8c or the ring 8b, dust or dust adheres to the recesses, causing mold generation or offensive odor. Therefore, the surfaces of the impeller 8a and the ring 8b are covered with a protective film made of a dust adhesion preventing material such as silicon or a fluorine material. The protective film made of this dust adhesion preventing material covers, for example, minute concave portions on the surface, thereby smoothing the minute concave portions formed on the surfaces of the wings 8c and the ring 8b, making the surface uniform and preventing dust from adhering to the surface. And The protective film made of the dust adhesion preventing material may be applied or sprayed with the dust adhesion preventing material, for example.

  This protective layer may be formed so as to cover both the wing 8c and the ring 8b, or may be provided with a protective layer on either one of them, or only a part where dust is easily attached is protected. You may comprise so that it may be covered with a layer.

  However, the step on the surface of the wing 8c to which dust easily adheres, the corners of the uneven surface such as the notch and the protrusion are easy to slip, so that the effect of preventing dust from being caught is great. That is, the minute concave portions formed on the surfaces of the blades 8c and the ring 8b of the impeller 8a can be eliminated and smooth, and adhesion of fine dust that cannot be removed by the filter 5, adsorption of odor, generation of mold, and odor release can be suppressed. In particular, the step 11 on the surface of the wing 8c where the dust easily adheres, the corners of the concave and convex surfaces such as the notch 15 and the protrusion 16 are easy to slip, so that the dust is not caught and the effect is great. As a result, the blade inner circumferential tip 13b and the blade pressure surface 13d, which are the inner side of the impeller 8a, can be kept clean, and a hygienic cross-flow fan can be obtained.

  Thus, it has at least two disk-shaped support plates 8b arranged at a predetermined interval, and a plurality of blades 8c whose both ends are fixed to the outer peripheral portion of the support plate 8b and extend in the rotation axis direction AX. The cross-flow fan 8 has a plurality of impellers 8d in the rotation axis direction AX, and the support plate 8b and the blades 8c are composed of a thermoplastic resin material containing glass fiber and a dust adhesion preventing material covering the thermoplastic resin material. As a result, the inner side of the impeller 8 can be kept clean, and a hygienic cross-flow fan can be obtained. Furthermore, a hygienic air conditioner can be obtained by installing this cross-flow fan.

  Although already described in the third embodiment and the fourth embodiment, in addition to the case where the projection portion 16 in the other embodiment is provided, the groove portion 14, the groove portion 14, and the notch portion 15 described in the other embodiments. The same effect can be obtained if it is formed symmetrically at the midpoint position in the impeller shaft direction between the rings 8b. That is, the flow is symmetrical in the impeller single unit 8d and the flow is stabilized. As a result, the flow is stabilized by the once-through fan 8, and even if ventilation resistance is added to the filter 5, the air can be stably blown.

  As described above, the step 11, the groove 14, the notch 15, and the protrusion of the blade 8 c are substantially line symmetric with respect to the center line that passes through the center of the blade 8 c in the rotation axis direction AX and is perpendicular to the rotation axis direction AX. By configuring the portion 16, the flow symmetry in the impeller single body 8d can be achieved and the flow can be stabilized. As a result, the flow is stabilized in the cross-flow fan 8 as a whole, and even if ventilation resistance is added to the filter, stable air can be blown. Therefore, a cross-flow fan capable of stable air blowing is obtained.

  Further, the notch 15 described in the third embodiment may be provided in the blade 8c having the configuration shown in the fourth and fifth embodiments. A rotating shaft is provided with a notch 15 provided at at least one end of the blade inner peripheral end and the blade outer peripheral end of the blade 8c and notched from the tip 13a, 13b of the end toward the inside of the blade 8c. By providing a plurality in the direction AX, in addition to the effects of the respective configurations, the rotational sound can be further reduced. The shape of the notch 15 is not limited to a V-shaped substantially triangle, and may be U-shaped or U-shaped.

  Moreover, if the notch part corner | angular part 15a of the front-end | tip of the notch part 15 is rounded, it will be easy to clean and a safe once-through fan will be obtained. That is, dust adheres to the impeller 8a, and when wiping the tip of the blade outer peripheral side of the impeller directly with a rag or the like, the finger is not injured such as the rag being cut even if wiping in the rotation axis direction AX, A high-quality cross-flow fan that ensures safety can be obtained.

  Any one of the once-through fans 8 shown in the first to fifth embodiments, and the heat exchanger 7 that is disposed in the suction-side flow path C1 formed by the once-through fan 8 and exchanges heat with the sucked air; By providing this, it is possible to obtain an air conditioner that can reduce noise. That is, by forming the protrusion 16, the groove 14, and the step 11 on the blade negative pressure surface 13 d side of the blade end of the impeller 8 a of the cross-flow fan 8, it is possible to obtain an air conditioner with a good audibility and a quietness. Further, by providing the notch 15 at the tip of the blade, it is possible to obtain an air conditioner that is audible and quiet. In addition, using the cross-flow fan 8 provided with a dust adhesion preventing material that covers the thermoplastic resin containing glass fibers, a sanitary air conditioner that is difficult to adhere dust can be obtained.

  Moreover, although Embodiment 1-Embodiment 5 demonstrated the structural example which mounted the cross-flow fan 8 in the air conditioner, for example, it does not restrict to this. For example, the present invention can be applied to a cross-flow fan mounted on another device such as an air curtain. By using a cross-flow fan that can reduce noise, there is an effect that the noise of a device equipped with the fan can be reduced.

It is an external appearance perspective view which shows the air conditioner carrying the cross-flow fan which concerns on Embodiment 1 of this invention. FIG. 5 is a longitudinal sectional view taken along line MM in FIG. 1 according to the first embodiment of the present invention. It is the schematic which shows the impeller of the crossflow fan which concerns on Embodiment 1 of this invention, Fig.3 (a) is a side view of a crossflow fan, FIG.3 (b) is the NN sectional view taken on the line of Fig.3 (a). FIG. It is explanatory drawing which shows the blade | wing which concerns on Embodiment 1 of this invention, Fig.4 (a) shows the blade negative pressure surface used as the back surface with respect to the rotation direction RO of a blade, FIG.4 (b) shows FIG.4 (a). It is a VV line sectional view of). It is explanatory drawing which shows the other structural example of the wing | blade which concerns on Embodiment 1 of this invention. It is explanatory drawing which shows the further another structural example of the wing | blade which concerns on Embodiment 1 of this invention. It is explanatory drawing which concerns on Embodiment 1 of this invention and shows the structure which provided the level | step difference in both the blade inner peripheral side edge part and a blade outer peripheral side edge part. It is the schematic which shows the impeller of the crossflow fan which concerns on Embodiment 2 of this invention, Fig.8 (a) is a side view of a crossflow fan, FIG.8 (b) is the HH sectional view taken on the line of Fig.8 (a). FIG. It is a perspective view which expands and shows the wing | blade which concerns on Embodiment 2 of this invention. It is explanatory drawing which expands and shows a part of blade negative pressure surface which concerns on Embodiment 2 of this invention. FIG. 11 is a cross-sectional view taken along the line PP in FIG. 10 according to the second embodiment of the present invention. It is explanatory drawing which expands and shows a part of blade negative pressure surface which concerns on Embodiment 2 of this invention. 6 is a graph showing a relationship between a groove side angle θ1 (°) that is an angle formed by both groove side portions of the groove portion and a noise reduction value {dB (A)} according to the second embodiment of the present invention. 11 is a graph showing a relationship between a ratio F1 / L1 of a groove deepest chord distance F1 and a chord line L length L1 and a noise reduction value {dB (A)} according to the second embodiment of the present invention. 12 is a graph showing a relationship between a groove center point distance F2 and an inter-ring blade length B ratio F2 / B and a noise reduction value {dB (A)} according to the second embodiment of the present invention. It is a perspective view which expands and shows the other structural example of the wing | blade which concerns on Embodiment 2 of this invention. It is a perspective view which expands and shows the wing | blade which concerns on Embodiment 3 of this invention. It is explanatory drawing which expands and shows a part of blade negative pressure surface which concerns on Embodiment 3 of this invention. It is explanatory drawing which expands and shows a part of blade negative pressure surface which concerns on Embodiment 3 of this invention. It is a perspective view which expands and shows the wing | blade which concerns on Embodiment 4 of this invention. It is explanatory drawing which expands and shows a part of blade negative pressure surface which concerns on Embodiment 4 of this invention. It is explanatory drawing which expands and shows a part of blade negative pressure surface which concerns on Embodiment 4 of this invention. FIG. 22 is a cross-sectional view taken along the line QQ in FIG. 21 according to the fourth embodiment of the present invention. FIG. 22 is a cross-sectional view taken along line RR in FIG. 21 according to the fourth embodiment of the present invention. It is a perspective view which expands and shows the wing | blade which concerns on Embodiment 5 of this invention. It is explanatory drawing which expands and shows a part of blade negative pressure surface which concerns on Embodiment 5 of this invention. It is explanatory drawing which expands and shows a part of blade negative pressure surface which concerns on Embodiment 5 of this invention. FIG. 27 is a cross-sectional view taken along the line TT in FIG. 26 according to the fifth embodiment of the present invention. FIG. 27 is a sectional view taken along the line SS of FIG. 26 according to the fifth embodiment of the present invention. It is a graph which concerns on Embodiment 5 of this invention and shows the relationship between groove side part angle | corner (theta) 2 (degree) which is an angle which both groove side parts of a projection part make, and noise reduction value {dB (A)}. It is explanatory drawing which expands and shows a part of blade | wing negative pressure surface of the other structural example concerning Embodiment 5 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioner main body 2 Suction port 3 Outlet 7 Heat exchanger 8 Cross-flow fan 8a Impeller 8b Support plate 8c Blade 8d Impeller single 8f Fan shaft 9 Stabilizer 10 Guide wall 11 Step 11a Step front edge 11b Step rear edge 12 motor 12a motor shaft 13a blade outer peripheral tip 13b blade inner peripheral tip 13c blade pressure surface 13d blade negative pressure surface 13e chord central portion 14 groove 14a groove inner end 14b groove side 14d groove connection step 15 notch 15a Cutout corner portion 15b Cutout portion side portion 16 Projection portion 16a Blade outer peripheral side inclined surface 16b Blade inner peripheral side inclined surface 16c Side surface 16e Corner portion 17 Groove portion 17a Groove inner end portion 17b Groove side portion AX Rotating shaft direction L Blade chord line L1 Length of chord line Ls Straight line parallel to chord line L and in contact with blade suction surface RO Rotation direction O Rotation center C1 Suction Frequency C2 blow-out area

Claims (7)

At least two disc-shaped support plates arranged at a predetermined interval, a shaft that passes through the center of the support plate and serves as a rotation shaft, and both ends are fixed to the outer peripheral portion of the support plate, and in the direction of the rotation shaft A plurality of blades extending in a cross section perpendicular to the rotation axis and having an arc shape between the blade outer circumferential end and the blade inner circumferential end, and a blade suction surface that is a rear surface with respect to the rotation direction of the blade. A recess extending in the direction of the rotation axis provided at at least one end of the blade outer peripheral end and the blade inner peripheral end, and the recess extends from the tip of the end to the blade suction surface. A once-through fan characterized in that it has a stepped shape extending obliquely so that the distance along it gradually increases or decreases. 2. The cross-flow fan according to claim 1, wherein a plurality of steps are provided in the direction of the rotation axis, and two adjacent steps are coupled to each other at different angles with respect to a tip end of the blade . Provided at at least one end of the blade inner peripheral end and the blade outer peripheral end of the blade, and a notch formed by cutting out from the tip of the end toward the inside of the blade The cross-flow fan according to claim 1 , wherein a plurality of the cross-flow fans are provided. 4. The once-through fan according to claim 3 , wherein a corner of the tip of the notch is rounded. 5. The blade according to claim 1 , wherein the blade is configured so as to be substantially line symmetric with respect to a center line perpendicular to the rotation axis direction through a central portion of the blade in the rotation axis direction. The once-through fan according to any one of the preceding claims. Wherein the front Symbol support plate wing has a thermoplastic resin material containing glass fiber, any of claims 1 to 5, characterized in that configured in dust adhesion preventing member covering the thermoplastic resin material 1 The once-through fan according to item. A cross-flow fan according to any one of claims 1 to 6 , and a heat exchanger disposed in a suction-side flow passage formed by the cross-flow fan and exchanging heat with the sucked air. An air conditioner characterized by that.

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