JP6625213B2 - Multi-blade fan and air conditioner - Google Patents

Description

  The present invention relates to a multi-blade fan with improved ventilation performance and an air conditioner provided with the multi-blade fan.

  BACKGROUND ART Conventionally, an air conditioner including a multi-blade fan such as a cross flow fan and a sirocco fan has been known. For example, Patent Literature 1 discloses an air conditioner including a cross flow fan. The cross-flow fan described in Patent Literature 1 has a configuration in which one end of the blade is disposed on the rotation direction front side with respect to the other end, and the blade is inclined in the circumferential direction. That is, the cross flow fan described in Patent Literature 1 employs a so-called skew type blade. Further, the cross flow fan described in Patent Literature 1 curves the outer peripheral end of the wing outward, and extends the rotational axis from the outer peripheral end of the wing from one end to the other end of the wing. The distance is the same.

  Here, the air conditioner provided with a cross flow fan is provided with a stabilizer (described as a nose in Patent Document 1) that partitions an air passage from an intake port to an air outlet into a suction side air path and an outlet side air path. I have. The tip of the stabilizer extends along the rotation axis of the cross flow fan and is arranged to face the cross flow fan. For this reason, when the blades of the cross flow fan pass near the tip of the stabilizer, pressure fluctuations occur between the two, and noise called so-called blade pitch sound is generated.

  The air conditioner described in Patent Literature 1 uses a cross flow fan having skew-type wings, so that the timing of passing through the stabilizer tip at each position of the wing is shifted. Since the generated pressure fluctuation can be suppressed, the blade pitch sound can be reduced. Further, in an air conditioner using a cross flow fan having skew type blades, a gap between a blade center portion and a stabilizer tip becomes large, and a problem that leakage loss in the gap increases. Have. The air conditioner described in Patent Literature 1 has the same distance between the rotation axis and the outer peripheral end of the wing from one end to the other end of the wing, so that one end of the wing is connected to the other end. In order to solve the problem, the gap between the stabilizer and the tip of the stabilizer is made constant toward the end of the stabilizer.

JP-A-10-18990

However, the cross flow fan and the air conditioner described in Patent Literature 1 have a problem that the air blowing performance is still insufficient.
Specifically, when the distance between the blades is viewed from the rotating shaft side of the cross flow fan, that is, from the inner circumferential end to the outer circumferential end, the position is closer to the inner circumferential end than to the blade center. Becomes larger. The cross flow fan described in Patent Literature 1 has a maximum thickness portion having the largest thickness at the center of the blade in a cross section perpendicular to the rotation axis. In other words, in the cross flow fan described in Patent Document 1, when blowing out the airflow, the airflow that has passed through the above-described location where the space between the blades is the largest passes through the space between the thickest portions where the space between the blades is the smallest. . For this reason, in the cross flow fan described in Patent Document 1, when blowing out an airflow, a loss of the flow occurs, and the blowing performance deteriorates.

  Further, the cross flow fan described in Patent Literature 1 has a skew type blade, and the direction of the airflow blown out from the cross flow fan is substantially perpendicular to the blade. Specifically, the direction of the airflow blown out from the cross flow fan is not a direction perpendicular to the rotation axis, but a direction bent from the front end to the rear end in the rotation direction of the blade. For this reason, in the air conditioner described in Patent Literature 1, a low-speed region is generated on the side wall of the outlet, and a backflow is likely to occur near the side wall at a high load. For this reason, in the air conditioner described in Patent Literature 1, the airflow from the outlet becomes unstable, and the air blowing performance deteriorates.

  The present invention has been made to solve the above-described problems, and provides a multi-blade fan capable of improving air blowing performance while suppressing noise, and an air conditioner including the multi-blade fan. The purpose is to:

A multi-blade fan according to the present invention includes a plurality of blades arranged on a concentric circle of a rotation axis, and each of the plurality of blades has a first end as an end in the rotation axis direction of each of the plurality of blades. And a second end, wherein the first end is disposed on the rotation direction front side with respect to the second end, and each of the plurality of wings further includes a respective one of the plurality of wings. As an end in the radial direction with the axis as the center, an outer end located on the outer periphery and an inner end located on the inner periphery, the plurality of blades in a cross section perpendicular to the rotation axis. In each case, the thickness of the inner peripheral side end is greater than the thickness of the outer peripheral side end, and the outer peripheral side of the inner peripheral side end, the chord line centering on the rotation axis. At the position on the inner peripheral side with respect to the circle passing through the midpoint of the maximum thickness portion having the largest thickness, Has a shape in which the thickness decreases toward the inner peripheral end, and the distance between the second end and the rotating shaft at the inner peripheral end is equal to the distance at the inner peripheral end. reduction of the wall thickness of toward the first end from said second end short rather, in the outer peripheral side end portion than the distance between the rotary shaft and the first end, the inner peripheral side The thickness is not more than a decrease in thickness from the second end to the first end on the end side .

  Further, the air conditioner according to the present invention is a casing in which an inlet and an outlet are formed, the multi-blade fan according to the present invention housed in the casing, and extends along the rotation axis of the multi-blade fan, And a diffuser having a protruding portion facing the multi-blade fan and disposed between the multi-blade fan and the outlet.

In the multi-blade fan according to the present invention, each of the plurality of blades has the first end disposed on the rotation direction front side of the second end. That is, the multi-blade fan according to the present invention has so-called skew type blades . For this reason, the multi-blade fan according to the present invention can suppress the blade pitch sound as in Patent Document 1 .

  Further, in the multi-blade fan according to the present invention, in the cross section perpendicular to the rotation axis, each of the plurality of blades has a greater thickness at the inner peripheral end than at the outer peripheral end, and On the outer peripheral side from the inner peripheral end, a maximum thickness portion having the largest thickness is provided at a position on the inner peripheral side with respect to a circle passing through the midpoint of the chord line with the rotation axis as the center, It has a shape in which the thickness decreases from the thick portion toward the inner peripheral end. Therefore, in the multi-blade fan according to the present invention, the blade-to-blade distance gradually increases from the inner peripheral end to the outer peripheral end. Therefore, the multi-blade fan according to the present invention can suppress the loss of the flow generated when blowing out the airflow.

Further, in the multi-blade fan according to the present invention, the distance between the second end at the inner peripheral end and the rotating shaft is the distance between the first end at the inner peripheral end and the rotating shaft. Shorter than. That is, in the multi-blade fan according to the present invention, the flow path formed between the blades is longer on the second end side on the rear side in the rotation direction than on the first end side on the front side in the rotation direction. In other words, in the multi-blade fan according to the present invention having the wings having the above-described shape that suppresses the flow loss, the velocity of the airflow near the inner peripheral end of the wing when blowing out the airflow is changed in the rotational direction. The second end portion on the rear side in the rotation direction is faster than the first end portion on the front side. For this reason, the multi-blade fan according to the present invention can correct the airflow at the time of blowing, which was conventionally bent from the front end to the rear end in the rotation direction of the blade, with the airflow at the second end. It can be blown out in a direction perpendicular to the rotation axis as compared with the conventional case. Further, in the multi-blade fan according to the present invention, the amount of decrease in the thickness from the second end to the first end on the outer peripheral end is equal to the first decrease from the second end on the inner peripheral end. The thickness is less than the amount of reduction in thickness toward the end. For this reason, in the multi-blade fan according to the present invention, the distance between the blades on the inner end side is smaller than the distance between the blades on the first end side. For this reason, the velocity of the airflow near the inner peripheral end of the blade when blowing out the airflow is higher on the second end side on the rear side in the rotation direction than on the first end side on the front side in the rotation direction. Therefore, the multi-blade fan according to the present invention can further correct the bent airflow.

  Therefore, the multi-blade fan and the air conditioner including the multi-blade fan according to the present invention can improve the air blowing performance while suppressing noise.

1 is an external perspective view illustrating an indoor unit of an air conditioner according to an embodiment of the present invention. It is the longitudinal section which looked at the indoor unit of the air conditioner concerning an embodiment of the invention from the side. It is an outline view showing a cross flow fan concerning an embodiment of the invention. It is an external appearance perspective view showing the impeller single body of the cross flow fan concerning an embodiment of the invention. It is AA sectional drawing of FIG. FIG. 6 is an enlarged view of a portion F in FIG. 5. It is sectional drawing of the 2nd end part of the blade | wing of the cross flow fan which concerns on embodiment of this invention. It is sectional drawing of the 1st end part of the blade | wing of the cross flow fan which concerns on embodiment of this invention. It is a perspective view which shows the principal part of another example of the indoor unit of the air conditioner which concerns on embodiment of this invention, and is a perspective view which shows the sirocco fan and the casing which accommodates this sirocco fan.

Embodiment.
Hereinafter, in the present embodiment, a multi-blade fan according to the present invention will be described using a cross-flow fan as an example. In the present embodiment, an air conditioner according to the present invention will be described by taking an indoor unit of an air conditioner equipped with a cross flow fan as an example.

FIG. 1 is an external perspective view illustrating an indoor unit of an air conditioner according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the indoor unit observed from the side.
As illustrated in FIG. 1, in the indoor unit 100, a casing of the indoor unit 100 is configured by a main body 1 and a front panel 1 b that is provided on a front surface of the main body 1 and that can be opened and closed. Here, in FIG. 1, the indoor unit 100 is installed on a wall 11a of a room 11, which is a space to be air-conditioned. That is, FIG. 1 illustrates an example in which the indoor unit 100 is a wall-mounted type, but is not limited thereto, and may be a ceiling-embedded type or the like. The indoor unit 100 is not limited to being installed in the room 11, and may be installed in, for example, a room in a building or a warehouse.

  As shown in FIGS. 1 and 2, a main body upper portion 1 a constituting an upper portion of the main body 1 has a plurality of openings 2 a corresponding to a suction port of the present invention in order to suck indoor air into the indoor unit 100. A suction grill 2 is formed. An outlet 3 for supplying conditioned air to the room is formed below the main body 1.

  Further, as shown in FIG. 2, the main body 1 includes a filter 5 for removing dust and the like in the air sucked from the opening 2 a of the suction grill 2 in an air passage from the opening 2 a of the suction grill 2 to the outlet 3. A heat exchanger 7 that transmits the hot or cold heat of the refrigerant to the air that has passed through the filter 5 to generate conditioned air, a stabilizer 9 that partitions the suction-side air passage E1 and the blow-out air passage E2, and a suction grill 2 A cross-flow fan 8 that sucks air from the opening 2a and blows air from the outlet 3, an up-down wind direction vane 4a and a right-left wind direction vane 4b that adjusts the direction of the air blown from the cross flow fan 8, and a cross-flow fan 8 And a diffuser 20 arranged between the air outlet 3 and the air outlet 3.

The opening 2 a of the suction grill 2 is an opening for forcing indoor air into the interior of the indoor unit 100 by the cross flow fan 8. Although FIGS. 1 and 2 show an example in which the suction grille 2 is formed only on the upper part 1a of the main body 1, it goes without saying that it may be formed on the front panel 1b. . Further, the shape of the suction grill 2 is not particularly limited.
The air outlet 3 is an opening through which the air is sucked from the opening 2a of the suction grill 2 and passed through the heat exchanger 7 when the air is supplied to the room.

  The filter 5 is formed, for example, in a mesh shape, and removes dust and the like in the air sucked from the opening 2 a of the suction grill 2. The filter 5 is provided downstream of the suction grill 2 and upstream of the heat exchanger 7 in an air passage (a central portion inside the main body 1) from the opening 2 a of the suction grill 2 to the outlet 3. .

The heat exchanger 7 (indoor heat exchanger) cools the indoor air as an evaporator during the cooling operation, and heats the indoor air as a condenser (radiator) during the heating operation. The heat exchanger 7 is provided downstream of the filter 5 and upstream of the cross flow fan 8 in an air passage (a central portion inside the main body 1) from the opening 2 a of the suction grill 2 to the outlet 3. ing. In FIG. 2, the shape of the heat exchanger 7 is such that it surrounds the front and back surfaces of the cross flow fan 8, but is not particularly limited.
It is assumed that the heat exchanger 7 is connected to an outdoor unit having a compressor, an outdoor heat exchanger, a throttling device and the like to constitute a refrigeration cycle. The heat exchanger 7 is, for example, a fin-and-tube heat exchanger including a heat transfer tube and a plurality of aluminum fins.

The cross flow fan 8 is for sucking room air from the opening 2 a of the suction grill 2 and blowing out conditioned air from the outlet 3. The cross flow fan 8 is provided downstream of the heat exchanger 7 and upstream of the air outlet 3 in an air path from the suction grill 2 to the air outlet 3 (a central portion inside the main body 1).
The details of the cross flow fan 8 will be described later.

  The stabilizer 9 is formed to protrude from the front side of the main body 1 into the air passage inside the main body 1. The distal end 9 a of the stabilizer 9 extends along the rotation axis O of the cross flow fan 8 and is arranged to face the cross flow fan 8. Thereby, the stabilizer 9 partitions the air path from the opening 2a of the suction grill 2 to the air outlet 3 into an air path E1 on the suction side and an air path E2 on the outlet side. Further, the stabilizer 9 is located below the lower end on the front side of the heat exchanger 7. For this reason, a drain pan 9 c that receives the drain water dropped from the heat exchanger 7 is formed on the upper surface of the stabilizer 9.

In the main body 1, a guide wall 10 is formed between the cross flow fan 8 and the outlet 3 to form a rear wall of the outlet-side air passage E <b> 2. The guide wall 10 forms a spiral slope that is inclined from the cross flow fan 8 to the outlet 3. The guide wall 10 faces the lower surface 9 b of the stabilizer 9. That is, the lower surface 9 b of the stabilizer 9 serves as an upper wall of the diffuser 20, and the guide wall 10 serves as a lower wall of the diffuser 20.
Here, the tip portion 9a of the stabilizer 9 corresponds to the projecting portion of the diffuser in the present invention.

The vertical wind direction vanes 4a adjust the vertical direction of the air blown from the cross flow fan 8, and the horizontal wind direction vanes 4b adjust the horizontal direction of the air blown from the cross flow fan 8. Things.
The vertical wind direction vanes 4a are provided downstream of the horizontal wind direction vanes 4b. The vertical wind direction vanes 4a are swingably attached to side surfaces of the main body 1, for example, as shown in FIG. The left and right wind direction vanes 4b are provided upstream of the vertical wind direction vanes 4a. The left and right wind direction vanes 4b are swingably attached to the lower surface 9b of the stabilizer 9 as shown in FIG. 2, for example.

  Subsequently, a detailed configuration of the cross flow fan 8 according to the present embodiment will be described.

FIG. 3 is an external view showing a cross flow fan according to the embodiment of the present invention. FIG. 4 is an external perspective view showing the impeller alone of the cross flow fan. FIG. 5 is a sectional view taken along line AA of FIG. FIG. 6 is an enlarged view of a portion F in FIG. FIG. 7 is a cross-sectional view of the second end of the blade of the cross flow fan. FIG. 8 is a cross-sectional view of the first end of the blade of the cross flow fan.
3 shows a front view of the cross flow fan 8 on the right side, in other words, a view of the cross flow fan 8 observed from the left side in FIG. FIG. 3 also shows a side view of the cross flow fan 8 on the left side. 7 and 8 are cross-sectional views of the cross flow fan 8 in a cross section perpendicular to the rotation axis O. In FIGS. 6 to 8, when the same configuration is distinguished between the first end portion 8ca and the second end portion 8cb, a symbol “a” is added to the first end portion 8ca side, and the second The symbol “a” is added to the end 8cb side.

  The cross flow fan 8 includes an impeller 8a made of a thermoplastic resin such as an AS resin. The impeller 8a includes a plurality of impellers 8d connected to each other. The impeller unit 8d is composed of a plurality of blades 8c and a support plate 8b fixed to the ends of the plurality of blades 8c. The plurality of blades 8c include an outer peripheral end 8g located on the outer peripheral side and an inner peripheral end 8h located on the inner peripheral side as radial ends around the rotation axis O of each of the wings 8c. Have. The plurality of blades 8c have a shape in which the pressure surface 8j and the negative pressure surface 8k are curved in the rotation direction RO from the rotation axis O toward the outer peripheral end 8g. The support plate 8b is a member having a circular outer periphery. The support plate 8b, which is not located at the end of the impeller 8a, has a hollow ring shape on the inner peripheral side. That is, the impeller 8a is a single impeller 8d in which a plurality of blades 8c arranged at predetermined intervals on the concentric circle of the rotation axis O project substantially perpendicularly from the outer periphery of the disc-shaped support plate 8b, A plurality is welded, connected and integrated.

  One end of the impeller 8a is connected to a fan motor 12 that rotates the impeller 8a about a rotation axis O via a motor shaft 12a. For this reason, a fan boss 8e fixed to the motor shaft 12a with screws or the like is provided on the support plate 8b on the end side of the impeller 8a so as to protrude inside the impeller 8a. A fan shaft 8f is provided on the other end of the impeller 8a, in other words, on the support plate 8b on the end side. The fan shaft 8f is rotatably held by the main body 1, for example. When the fan motor 12 is energized, the impeller 8a rotates in the rotation direction RO around the rotation axis O of the impeller 8a while both ends are supported, and the impeller 8a extends from the opening 2a of the suction grill 2 to the room. Air can be sucked in and air-conditioned air can be sent to the outlet 3.

  Here, each of the blades 8c of the cross flow fan 8 according to the present embodiment is configured as follows.

  The wing 8c has a first end 8ca and a second end 8cb as ends of the wing 8c in the rotation axis O direction. Further, the wing 8c is arranged such that the first end 8ca is located on the rotation direction front side by a specified angle θ with respect to the second end 8cb. In other words, the first end 8ca is advanced in the rotation direction RO by the specified angle θ from the second end 8cb. For this reason, the wing 8c is inclined at a prescribed angle δ in the circumferential direction with respect to the rotation axis O. That is, the wing 8c is a so-called skew type wing.

  In the case of a cross flow fan whose blades are not inclined with respect to the rotation axis, when the blades of the cross flow fan pass near the tip of the stabilizer, the timing of passing through the tip of the stabilizer at each position of the blade becomes the same. For this reason, pressure fluctuation occurs between the two, and noise called so-called blade pitch sound is generated. On the other hand, in the blade 8c of the cross flow fan 8 according to the present embodiment, when the blade 8c passes near the tip 9a of the stabilizer 9, the timing at which the blade 8c passes through the tip 9a of the stabilizer 9 is shifted. Since the pressure fluctuation generated between the tip 9a of the stabilizer 9 and the blade 8c can be suppressed, the blade pitch sound can be reduced.

Further, in blade 8c of cross flow fan 8 according to the present embodiment, rotation axis O and outer peripheral end 8g have the same distance from first end 8ca to second end 8cb (FIG. 6 to 8 at the position of the radius Rt). In a conventional skew type blade in which the blade is simply inclined with respect to the rotation axis, the gap between the center of the blade and the tip of the stabilizer becomes large, and the leakage loss in the gap increases. On the other hand, by forming the outer peripheral end 8g of the wing 8c as in the present embodiment, the gap between the wing 8c and the tip 9a of the stabilizer 9 can be made constant, and the leakage loss in the gap can be suppressed. it can.
That is, in the multi-blade fan according to the present embodiment, the distance between the outer peripheral end of the blade and the rotation axis is the same from the first end to the second end. For this reason, the multi-blade fan according to the present embodiment can suppress the leakage loss occurring at the center of the blade as in Patent Document 1.

The blade 8c of the cross flow fan 8 according to the present embodiment has a greater thickness at the inner peripheral end 8h than at the outer peripheral end 8g in a cross section perpendicular to the rotation axis O. ing. Furthermore, the blade 8c of the cross flow fan 8 according to the present embodiment is located at a position closer to the outer periphery than the inner peripheral end 8h, and is in contact with the outer peripheral end 8g and the inner peripheral end 8h. A maximum thickness portion having the largest thickness is provided at a position passing through the midpoint La of the chord line L and on the inner peripheral side of the circle RLa about the rotation axis O. For example, the maximum thickness portion at the first end 8ca is a maximum thickness portion Tamax. The maximum thickness at the second end 8cb is the maximum thickness Tbmax. That is, the wing 8c has a shape in which the thickness decreases from the maximum thickness portion toward the inner peripheral end 8h.
The thickness of the blade 8c is a diameter of a circle having a diameter larger than 0 mm and inscribed in the pressure surface 8j and the suction surface 8k in a cross section perpendicular to the rotation axis O.

  In a conventional crossflow fan that does not have a maximum thickness portion at a position as in the present embodiment, when the distance between the blades is viewed from the inner peripheral end side to the outer peripheral end side of the blade, The interval between the inner peripheral end and the inner peripheral end is larger than that of the wing center. That is, in the conventional crossflow fan, the distance between the blades does not gradually increase from the inner peripheral end to the outer peripheral end. For this reason, when blowing out the airflow from the cross flow fan, a loss of the flow occurs, and the blowing performance deteriorates. On the other hand, in the cross flow fan 8 including the blade 8c according to the present embodiment whose wall thickness changes as described above, the distance between the blades 8c gradually increases from the inner peripheral end 8h to the outer peripheral end 8g. It is getting bigger. Therefore, the cross flow fan 8 according to the present embodiment can suppress loss of the flow generated when blowing out the air flow. In the cross flow fan 8 according to the present embodiment, when the airflow is sucked, the distance between the blades 8c gradually decreases from the outer peripheral end 8g to the inner peripheral end 8h. . For this reason, since the airflow sucked into the cross flow fan 8 is rectified between the blades 8c, the separation vortex can be suppressed, and noise caused by the separation vortex such as a rotating sound can be suppressed.

  Further, in blade 8c of cross flow fan 8 according to the present embodiment, the distance between second end 8cb at inner peripheral end 8h and rotation axis O is the first distance at inner peripheral end 8h. It is shorter than the distance between the end 8ca and the rotation axis O. In other words, the distance Rib between the inner peripheral end 8hb and the rotation axis O is shorter than the distance Ria between the inner peripheral end 8ha and the rotation axis O. More specifically, the distance between the inner peripheral end 8h and the rotation axis O decreases from the first end 8ca to the second end 8cb.

  In a conventional crossflow fan having skew-type blades, the direction of the blown air flow is substantially perpendicular to the blades. Specifically, the direction of the airflow blown out from the cross flow fan is not a direction perpendicular to the rotation axis, but a direction bent from the front end to the rear end in the rotation direction of the blade. For this reason, in the air conditioner having such a conventional crossflow fan, a low-speed region is generated on the side wall of the outlet, and a backflow is likely to occur near the side wall at a high load. For this reason, in the air conditioner having such a conventional crossflow fan, the airflow from the outlet becomes unstable, and the air blowing performance deteriorates.

  On the other hand, in the cross flow fan 8 according to the present embodiment, the distance between the second end 8cb at the inner end 8h and the rotation axis O is equal to the distance between the first end 8ca at the inner end 8h. It has a wing 8c that is shorter than the distance from the axis O. That is, in the cross flow fan 8 according to the present embodiment, the flow path formed between the blades 8c is closer to the second end 8cb on the rear side in the rotation direction than the first end 8ca on the front side in the rotation direction. Is getting longer. In other words, in the cross flow fan 8 according to the present embodiment having the wings 8c having the above-described shape capable of suppressing the flow loss at the time of blowing out the airflow, the vicinity of the inner peripheral end 8h of the wings 8c when blowing out the airflow is provided. The speed of the airflow is higher on the second end 8cb side on the rear side in the rotation direction than on the first end 8ca side on the front side in the rotation direction. For this reason, the cross flow fan 8 according to the present embodiment changes the airflow at the time of blowing, which has conventionally been bent from the front end to the rear end in the rotation direction of the blade, at the second end 8cb side. It can be corrected by airflow, and can be blown out in a direction perpendicular to the rotation axis O more than before.

  As described above, the crossflow fan 8 according to the present embodiment and the indoor unit 100 including the crossflow fan 8 can improve the air blowing performance while suppressing noise. That is, the high-quality indoor unit 100 with energy saving can be obtained.

  Further effects can be obtained by appropriately combining the configuration of the following modified example with the configuration of the wing 8c described above.

(Modification 1 of wing 8c)
The amount of reduction in thickness from the second end 8cb to the first end 8ca on the outer end 8g is determined by the thickness from the second end 8cb to the first end 8ca on the inner end 8h. May be equal to or less than the decrease amount. More specifically, as shown in FIGS. 7 and 8, the thickness of the first end 8ca at the position of the radius Rt1 from the rotation axis O is defined as the thickness T1a. The thickness of the second end 8cb at the position of the radius Rt1 from the rotation axis O is defined as the thickness T1b. The thickness of the first end 8ca at a position of a radius Rt2 smaller than the radius Rt1 from the rotation axis O is defined as a thickness T2a. The thickness of the second end 8cb at the position of the radius Rt2 from the rotation axis O is defined as the thickness T2b. At this time, (T1b−T1a) ≦ (T2b−T2a).

  By providing the wing 8c with such a configuration, the difference in distance between the adjacent wings 8c on the outer peripheral end 8g side can be the same or smaller on the first end 8ca side and the second end 8cb side. . Therefore, when the airflow is sucked into the cross flow fan 8, the separation vortex can be suppressed, and noise caused by the separation vortex such as a rotating sound can be suppressed. Further, the difference in the intake air volume between the first end portion 8ca side and the second end portion 8cb side can be reduced, and the area between the blades 8c on the outer peripheral side end portion 8g side can be increased. Efficiency can be improved. Further, since the area between the blades 8c on the outer peripheral side end 8g side can be enlarged, when blowing out the airflow from the cross flow fan 8, the blowing wind speed can be reduced. Therefore, the shaft torque generated in the fan motor 12 due to the friction loss can be reduced, and the efficiency of the cross flow fan 8 can be improved. That is, it is possible to obtain the indoor unit 100 with further energy saving.

  In addition, by providing the wing 8c with such a configuration, the distance between the wings 8c on the second end 8cb side on the inner peripheral end 8h side is larger than the distance between the wings 8c on the first end 8ca side. Is also smaller. For this reason, the velocity of the airflow near the inner peripheral end 8h of the wing 8c when blowing out the airflow is higher on the second end 8cb side on the rear side in the rotation direction than on the first end 8ca side on the front side in the rotation direction. It gets even faster. Therefore, the bending of the blown airflow can be further corrected, and the blowing performance of the crossflow fan 8 can be further improved.

(Modification 2 of wing 8c)
The negative pressure surface 8k may have a first step 8i extending along the rotation axis O direction and having a concave outer peripheral side. For example, as shown in FIGS. 6 to 8, a first step 8 i is formed at a position at a distance Ri from the rotation axis O. Thereby, when blowing out the airflow from the cross flow fan 8, the negative pressure generated in the first step 8i can promote the reattachment of the airflow likely to be separated from the negative pressure surface 8k. Further, since the area between the blades 8c on the outer peripheral side end 8g side can be enlarged, when blowing out the airflow from the cross flow fan 8, the blowing wind speed can be reduced. For this reason, the efficiency of the cross flow fan 8 can be improved, and the indoor unit 100 with further energy saving can be obtained.

  When the configuration of the first modification and the configuration of the second modification are combined, the height of the first step 8i may be increased from the first end 8ca to the second end 8cb. As described above, in the first modification, the velocity of the airflow near the inner peripheral end 8h of the blade 8c at the time of blowing out the airflow is the second airflow velocity behind the first end 8ca closer to the front in the rotational direction. The end 8cb side is even faster. For this reason, the separation of the airflow is likely to occur on the second end 8cb side. However, by increasing the height of the first step 8i on the second end 8cb side, the negative pressure generated at the first step 8i can be increased, and the separation of the airflow on the second end 8cb side can be suppressed.

(Modification 3 of wing 8c)
In a cross section perpendicular to the rotation axis O, the suction surface 8k may be formed by a plurality of arcs having different radii. Further, in a cross section perpendicular to the rotation axis O, the pressure surface 8j may be formed by at least one arc. Then, in a cross section perpendicular to the rotation axis O, the negative pressure surface 8k and the pressure surface 8j may have a configuration in which one side is connected to the arc and the other side is connected to the inner peripheral end 8h.

For example, the negative pressure surface 8k is configured as shown in FIGS. More specifically, at the first end 8ca, the negative pressure surface 8k is formed by an arc having a radius Rka1 on the outer peripheral end 8g side. Further, the negative pressure surface 8k is formed such that the inner peripheral side of the arc having the radius Rka1 is an arc having the radius Rka2. Further, the negative pressure surface 8k is formed such that the inner peripheral side of the arc having the radius Rka2 is an arc having a radius Rka3. The negative pressure surface 8k has a straight line portion 8Lka connected on one side to an arc having a radius Rka3 and connected on the other side to the inner peripheral end 8h. On the other hand, in the second end 8cb, the negative pressure surface 8k is formed by an arc having a radius Rkb1 on the outer peripheral end 8g side. Further, the negative pressure surface 8k is formed such that the inner peripheral side of the arc having the radius Rkb1 is an arc having a radius Rkb2. Further, the negative pressure surface 8k is formed such that the inner peripheral side of the arc having the radius Rkb2 is an arc having the radius Rkb3. The negative pressure surface 8k has a straight portion 8Lkb connected on one side to an arc having a radius Rkb3 and connected on the other side to the inner peripheral end 8h.
That is, the negative pressure surface 8k is configured such that a plurality of curved surfaces having different radii are connected from the outer peripheral end 8g side to the inner peripheral end 8h side, and has a flat surface on the inner peripheral end 8h side.

Further, for example, the pressure surface 8j is configured as shown in FIGS. Specifically, at the first end 8ca, the pressure surface 8j is formed by an arc having a radius Rja1. The pressure surface 8j has a straight portion 8Lja connected on one side to an arc having a radius Rja1 and connected on the other side to the inner peripheral end 8h. On the other hand, in the second end 8cb, the pressure surface 8j is formed by an arc having a radius Rjb1 on the outer end 8g side. The pressure surface 8j is formed by an arc having a radius Rjb2 on the inner peripheral side of the arc having a radius Rjb1. The pressure surface 8j has a straight portion 8Ljb, one side of which is connected to an arc having a radius Rjb2 and the other side of which is connected to an inner peripheral end 8h.
That is, the pressure surface 8j has a configuration in which at least one curved surface is formed from the outer peripheral end 8g side to the inner peripheral end 8h side, and has a flat surface on the inner peripheral end 8h side.

  By configuring the negative pressure surface 8k in this manner, when the airflow is sucked into the cross flow fan 8, the airflow that is likely to be separated from the negative pressure surface 8k at the outer peripheral side curved surface portion is converted to the inner peripheral side curved surface portion having a different arc radius. It can be reattached and flow loss can be suppressed. Further, by configuring the pressure surface 8j in this way, when the airflow is sucked into the cross flow fan 8, the pressure of the airflow can be gradually increased, and the friction loss between the pressure surface 8j and the airflow can be reduced. Can be suppressed. Further, since the airflow is sucked into the cross flow fan 8 by having the linear portions 8Lja, 8Ljb, 8Lka, 8Lkb on the inner peripheral side end 8h side of the blade 8c, the airflow which is likely to be separated from the negative pressure surface 8k at the curved surface portion. Can be reattached at the linear portion. For this reason, fluid abnormal noise due to local peeling can be suppressed.

(Modification 4 of wing 8c)
The wing 8c may be configured such that the wall thickness decreases from the second end 8cb to the first end 8ca at the same radius from the rotation axis O. For example, as shown in FIGS. 7 and 8, at the position of the radius Rt1, the thickness T1a of the first end 8ca is smaller than the thickness T1b of the second end 8cb. At the position of the radius Rt2, the thickness T2a of the first end 8ca is smaller than the thickness T2b of the second end 8cb.

  As shown in FIG. 4, in the present embodiment, the wing 8c and the support plate 8b are integrally formed of resin into a shape in which the second end 8cb of the wing 8c and the support plate 8b are connected. That is, when the wing 8c and the support plate 8b are formed by resin molding, the wing 8c and the support plate 8b are simultaneously formed in the same mold in a shape in which the second end 8cb of the wing 8c and the support plate 8b are connected. I have. By configuring the wing 8c as in Modification 4, the wing 8c has a tapered shape from the second end 8cb to the first end 8ca. For this reason, when the blade 8c and the support plate 8b are integrally formed of resin as shown in FIG. 4, the resin can be easily injected into the mold, and the contact between the blade 8c and the mold at the time of release can be suppressed. Therefore, by adopting the configuration of Modification 4 to the blade 8c, the productivity of the cross flow fan 8 can be improved.

(Modification 5 of wing 8c)
For example, as shown in FIGS. 7 and 8, the outer peripheral end 8g may have an arc surface having a radius Rt concentric with the outer periphery of the support plate 8b in a cross section perpendicular to the rotation axis O. The negative pressure surface 8k may have a second step 8gh in which the inner peripheral side is recessed at an inner peripheral end of the arc surface.

  For example, when dust or the like accumulates on the filter 5, the incident angle of the airflow sucked into the cross flow fan 8 may increase as indicated by the white arrows in FIGS. Even in such a case, by employing the configuration of the fifth modification, when the airflow flows between the blades 8c, the airflow flows along the arc surface. Then, the negative pressure generated in the second step 8gh can prevent the airflow from separating from the negative pressure surface 8k. That is, it is possible to obtain the cross flow fan 8 which has a high peeling resistance and is hard to stall even when the incident angle of the air current is large. That is, it is possible to obtain the cross flow fan 8 whose blowing characteristics are hard to change, and to obtain the high quality indoor unit 100.

(Modification 6 of wing 8c)
For example, as shown in FIGS. 7 and 8, the outer end 8g of the blade 8c may be located on the inner peripheral side of the outer periphery of the support plate 8b having a radius Rr about the rotation axis O. Thereby, even if the cross flow fan 8 or the indoor unit 100 is dropped, damage to the wing 8c can be prevented.

  As described above, in the present embodiment, the multi-blade fan according to the present invention has been described using the cross flow fan 8 as an example. However, the multi-blade fan according to the present invention is not limited to the cross flow fan 8, but may be a sirocco fan.

FIG. 9 is a perspective view illustrating a main part of another example of the indoor unit of the air conditioner according to the embodiment of the present invention, and is a perspective view illustrating a sirocco fan and a casing that houses the sirocco fan.
The sirocco fan 210 is provided with a plurality of blades 211 between support plates 212, similarly to the cross flow fan 8. Further, the blades 211 of the sirocco fan 210 are arranged on the concentric circle of the rotating shaft 213 at predetermined intervals, similarly to the blades 8c of the cross flow fan 8. The sirocco fan 210 is configured to blow airflow from between the blades 211 as in the cross flow fan 8.

  The indoor unit using the sirocco fan 210 includes a casing 200 in which an inlet 201 and an outlet 202 are formed. The sirocco fan 210 is housed in the casing 200. The casing 200 accommodating the sirocco fan 210 also includes a diffuser 203 disposed between the sirocco fan 210 and the air outlet 202, similarly to the main body 1 of the casing accommodating the cross flow fan 8. The diffuser 203 has a protrusion 204 that extends along the rotation axis 213 of the sirocco fan 210 and is arranged to face the sirocco fan 210.

  For this reason, by employing the configuration of the wing 8c described above for the wing 211 of the sirocco fan 210, it is possible to obtain the above-described effects other than the effect at the time of sucking the airflow.

  Reference Signs List 1 main body, 1a main body upper part, 1b front panel, 2 suction grille, 2a opening, 3 outlet, 4a vertical wind vane, 4b horizontal wind vane, 5 filter, 7 heat exchanger, 8 cross flow fan, 8a impeller, 8b Support plate, 8c blade, 8ca first end, 8cb second end, 8d impeller unit, 8e fan boss, 8f fan shaft, 8g outer end, 8gh second step, 8h inner end, 8i 1st step, 8j pressure surface, 8k negative pressure surface, 8Lja, 8Ljb, 8Lka, 8Lkb linear portion, 9 stabilizer, 9a tip portion, 9b lower surface portion, 9c drain pan, 10 guide wall, 11 room, 11a wall, 12 fan motor, 12a Motor shaft, 20 diffuser, 100 indoor unit, 200 casing, 201 suction port, 20 Outlet 203 diffuser, 204 projecting part, 210 sirocco fan, 211 wing, 212 support plate, 213 rotation axis, E1 suction side air path, E2 air outlet side air path, L chord line, La middle point, O rotation axis, Ri , Ria, Rib distance, Rja1, Rka1, Rka2, Rka3, Rjb1, Rjb2, Rkb1, Rkb2, Rkb3 radius, RLa circle, RO rotation direction, Rr radius, Rt radius, Rt1, Rt2 radius, T1a, T1b, T2a, T2b Thickness, Tamax, Tbmax Maximum thickness part.

Claims (11)

Equipped with a plurality of wings arranged on a concentric circle of the rotation axis,
Each of the plurality of wings has a first end and a second end as ends of the plurality of wings in the rotation axis direction, and the first end is more rotated than the second end. It is located on the front side in the direction,
Each of the plurality of blades further includes, as radial ends around the rotation axis of each of the plurality of blades, an outer peripheral end located on an outer peripheral side and an inner peripheral end located on an inner peripheral side. Part
In the cross section perpendicular to the rotation axis, each of the plurality of blades has a greater thickness at the inner peripheral end than at the outer peripheral end, and a greater thickness than the inner peripheral end. On the outer peripheral side, a maximum thickness portion having the largest thickness is provided at a position on the inner peripheral side with respect to a circle passing through the midpoint of the chord line with the rotation axis as the center, and from the maximum thickness portion to the inner portion. It has a shape in which the wall thickness decreases toward the peripheral end,
The distance between the rotary shaft and the second end portion of the inner peripheral end is rather short than the distance between said rotation axis and the first end portion of the inner peripheral end portion,
The amount of decrease in the thickness from the second end to the first end on the outer peripheral end is the thickness from the second end to the first end on the inner peripheral end. Multi-blade fan that is less than the reduction amount .   2. The multi-blade fan according to claim 1, wherein the rotating shaft and the outer peripheral side end have the same distance from the first end to the second end. 3. 3. The multi-blade fan according to claim 1, wherein the blade has a first step on the negative pressure surface on the outer peripheral side thereof. 3. The blade has a first step on the negative pressure surface, the outer peripheral side of which is concave,
3. The multi-blade fan according to claim 1, wherein the height of the first step increases from the first end to the second end. 4. The pressure surface and the suction surface of the blade are curved in the direction of rotation of the blade from the rotation axis toward the outer peripheral end,
In a cross section perpendicular to the rotation axis,
The suction surface of the blade is formed by a plurality of arcs having different radii,
The pressure surface of the wing is formed by at least one arc,
The multi-layer structure according to any one of claims 1 to 4 , wherein the pressure surface and the suction surface of the blade have a linear portion having one side connected to the arc and the other side connected to the inner peripheral end. Tsubasa fan. At a position of the same radius from the rotation axis,
The multi-blade fan according to any one of claims 1 to 5 , wherein a thickness of the blade is reduced from the second end to the first end. The multi-blade fan according to any one of claims 1 to 6 , further comprising a support plate connected to the first end or the second end of the blade and having a circular outer periphery. Said wings,
The outer peripheral end has an arc surface that is concentric with the outer periphery of the support plate in a cross section perpendicular to the rotation axis,
The multi-blade fan according to claim 7 , wherein the negative pressure surface has a second step with a concave inner peripheral side at an inner peripheral end of the arc surface. The outer edge portion of the blade, multiblade fan according to claim 7 or claim 8 located on the inner peripheral side than the outer periphery of the support plate. A casing in which an inlet and an outlet are formed,
The multi-blade fan according to any one of claims 1 to 9 , which is housed in the casing,
A diffuser extending along the rotation axis of the multi-blade fan, having a protrusion facing the multi-blade fan, and disposed between the multi-blade fan and the outlet;
Air conditioner equipped with. The multi-blade fan is a cross flow fan,
A stabilizer that partitions an air path in the casing from the suction port to the air outlet into a suction-side air path and a blow-side air path,
The air conditioner according to claim 10 , wherein the protrusion is an end of the stabilizer.

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