CN110914550B - Indoor unit of air conditioner - Google Patents

Abstract

An indoor unit of an air conditioner is provided with a cross flow fan, and an impeller of the cross flow fan is provided with: a plurality of blades each having a first end and a second end as ends in a direction along the rotation axis; and a support plate that supports a first end of each of the plurality of blades, wherein a second end is disposed forward of the first end in a rotation direction of the impeller, wherein each of the plurality of blades has an inner circumferential end and an outer circumferential end as ends in a radial direction about the rotation axis, wherein the inner circumferential end has a larger thickness than the outer circumferential end, and wherein each of the plurality of blades has a maximum thickness on an inner circumferential side than a straight line passing through a midpoint of a chord line of each of the plurality of blades and perpendicular to the chord line of the blade.

Description

Indoor unit of air conditioner

Technical Field

The present invention relates to an indoor unit of an air conditioner including a cross flow fan.

Background

Patent document 1 describes a cross flow fan in which a plurality of impellers are stacked in the direction of the rotation center line. Each of the plurality of impellers includes a support plate and a plurality of blade sections formed on a main surface of the support plate. The cross section perpendicular to the rotation center line of each blade portion becomes smaller from the root portion toward the tip portion. Further, the center of a cross section perpendicular to the rotation center line of each blade portion is displaced toward the front side in the rotation direction and radially outward from the root portion toward the tip portion.

Patent document 1: japanese patent application laid-open No. 2010-101222

In the cross-sectional view perpendicular to the rotation center line, each blade portion of the cross-flow fan described in patent document 1 has the following thickness distribution: the wall thickness of the central portion between the outer end portion and the inner end portion is approximately the maximum wall thickness, and the wall thickness is smaller as the central portion is farther away from the outer end portion or the inner end portion, and the wall thickness of both the outer end portion and the inner end portion is the minimum wall thickness. When each blade portion of the cross flow fan has such a thickness distribution, the flow of air is likely to be separated from the blade surface, and therefore, there is a problem that the efficiency of the cross flow fan may be reduced.

Disclosure of Invention

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an indoor unit of an air conditioner capable of improving the efficiency of a cross flow fan.

An indoor unit of an air conditioner according to the present invention includes: a housing having a suction port and a blow-out port; and a cross flow fan housed in the casing, wherein the cross flow fan includes: an impeller disposed in an air passage formed in the housing; a stabilizer that divides the air passage into a suction-side air passage and a discharge-side air passage; and a baffle wall that guides the air blown out from the impeller to the outlet-side air passage to the outlet port, the impeller including: a plurality of blades which are respectively arranged on a circumference around a rotation shaft of the impeller and respectively have a first end and a second end as ends along the rotation shaft; and a support plate that supports the first end portion of each of the plurality of blades, the second end portion being disposed forward of the first end portion in a rotation direction of the impeller, each of the plurality of blades having an inner circumferential end portion and an outer circumferential end portion as end portions in a radial direction with respect to the rotation shaft, a cross-sectional area of the second end portion in a cross-section perpendicular to the rotation shaft being smaller than a cross-sectional area of the first end portion in a cross-section perpendicular to the rotation shaft, a distance between the rotation shaft and the outer circumferential end portion at the second end portion being shorter than a distance between the rotation shaft and the outer circumferential end portion at the first end portion, a distance between the rotation shaft and the inner circumferential end portion at the second end portion being longer than a distance between the rotation shaft and the inner circumferential end portion at the first end portion, and a cross-section perpendicular to the rotation shaft, the inner circumferential end has a larger thickness than the outer circumferential end, the plurality of blades have a maximum thickness on the inner circumferential end side than a straight line passing through a midpoint of a chord line of each of the plurality of blades and perpendicular to the chord line of each of the plurality of blades in a cross section perpendicular to the rotation axis, the cross section perpendicular to the rotation axis in the first end is a first cross section of each of the plurality of blades, the cross section perpendicular to the rotation axis in the second end is a second cross section of each of the plurality of blades, an inscribed circle contacting the outer circumferential end, the pressure surface of each of the plurality of blades, and the negative pressure surface of each of the plurality of blades in the first cross section is a first inscribed circle, and an inscribed circle contacting the outer circumferential end, the pressure surface, and the negative pressure surface in the second cross section is a second inscribed circle, when an inscribed circle in contact with the inner circumference side end portion, the pressure surface, and the suction surface in the first cross section is taken as a third inscribed circle, and an inscribed circle in contact with the inner circumference side end portion, the pressure surface, and the suction surface in the second cross section is taken as a fourth inscribed circle, a distance between the rotation axis and a center of the first inscribed circle is equal to a distance between the rotation axis and a center of the second inscribed circle, and a distance between the rotation axis and a center of the third inscribed circle is equal to a distance between the rotation axis and a center of the fourth inscribed circle.

On the suction side of the impeller, air flows from the outer peripheral end portion toward the inner peripheral end portion of the blade. In the present invention, since the maximum thickness portion is formed on the inner peripheral side of the blade, even if the flow of air tries to peel off from the blade surface on the outer peripheral side of the blade, the peeling can be suppressed by the maximum thickness portion of the blade in which the inter-blade distance is reduced.

On the blowing side of the impeller, air flows from the inner circumferential end of the blade toward the outer circumferential end. On the outlet side of the impeller, the inflow angle of air to the blades is more likely to change than on the inlet side of the impeller due to flow fluctuations. In the present invention, since the wall thickness of the inner circumferential end portion which is the leading edge is larger than the wall thickness of the outer circumferential end portion, the occurrence of peeling can be prevented even if the inflow angle of air changes.

Therefore, according to the indoor unit of an air conditioner of the present invention, the efficiency of the cross flow fan can be improved.

Drawings

Fig. 1 is an external perspective view showing a structure of an indoor unit 100 of an air conditioner according to embodiment 1 of the present invention.

Fig. 2 is a side view showing an internal structure of an indoor unit 100 of an air conditioner according to embodiment 1 of the present invention.

Fig. 3 is an external view showing the structures of the impeller 8a and the motor 12 in the indoor unit 100 of the air conditioner according to embodiment 1 of the present invention.

Fig. 4 is an external perspective view showing the structure of an impeller unit 8d in an indoor unit 100 of an air conditioner according to embodiment 1 of the present invention.

Fig. 5 is a side view showing the structure of an impeller unit 8d in an indoor unit 100 of an air conditioner according to embodiment 1 of the present invention.

Fig. 6 is an enlarged view of a VI portion of fig. 5.

Fig. 7 is a sectional view showing a part of the section VII-VII of fig. 3.

Fig. 8 is a sectional view showing a part of the section VIII-VIII of fig. 3.

Fig. 9 is a sectional view showing a part of the section IX-IX of fig. 3.

Fig. 10 is a view showing a virtual state in which the cross sections of the first end portion 8ca, the second end portion 8cb, and the middle portion 8cc are superimposed on the same plane such that the centers 8gma, 8gmb, and 8gmc coincide with each other and the centers 8hma, 8hmb, and 8hmc coincide with each other in the impeller unit 8d of the indoor unit 100 of an air conditioner according to embodiment 1 of the present invention.

Fig. 11 is a graph showing a relationship between a rotational displacement angle ratio a of the vane 8c and a motor input ratio in the cross flow fan 8 of the indoor unit 100 of the air conditioner according to embodiment 1 of the present invention.

Fig. 12 is a graph showing a relationship between tmax/L and a motor input ratio in the cross flow fan 8 of the indoor unit 100 of the air conditioner according to embodiment 1 of the present invention.

FIG. 13 is a graph showing the relationship of tmax/t2 and the motor input ratio in the crossflow fan 8 satisfying the relationship of 0.045. ltoreq. tmax/L. ltoreq.0.080.

Fig. 14 is a graph showing a relationship between P/(2 × Rt) and a motor input ratio in the cross flow fan 8 of the indoor unit 100 of the air conditioner according to embodiment 1 of the present invention.

Detailed Description

Embodiment 1.

An indoor unit of an air conditioner according to embodiment 1 of the present invention will be described. Fig. 1 is an external perspective view showing a structure of an indoor unit 100 of an air conditioner according to the present embodiment. Fig. 2 is a side view showing an internal structure of the indoor unit 100 of the air conditioner according to the present embodiment. In fig. 1 and 2, a wall-mounted indoor unit 100 provided on a wall 11a of a room 11 as an air-conditioning target space is illustrated, but the indoor unit 100 may be an indoor unit of another type such as a ceiling-embedded type. The room 11 is not necessarily limited to a living room in a house, and may be an office, a warehouse, or the like.

As shown in fig. 1 and 2, the indoor unit 100 includes a casing 1 that houses internal devices. The housing 1 has: a housing main body 1a mounted on a wall 11 a; and a front panel 1b provided on the front surface of the case main body 1a and openable and closable. A suction grill 2 is formed on the top surface 1c of the casing main body 1 a. The suction grill 2 has a plurality of openings 2a formed therein as a suction port for sucking indoor air into the indoor unit 100. The suction grill 2 may be formed not only on the top surface 1c of the casing main body 1a but also on the front surface panel 1 b. The shape of the suction grill 2 is not particularly limited.

An air outlet 3 for blowing out the conditioned air into the room is formed in a lower portion of the casing main body 1 a. The air outlet 3 is provided with: an up-down wind direction plate 4a for adjusting the wind direction of the air-conditioning air in the up-down direction; and a left and right wind direction plate 4b for adjusting the wind direction of the air-conditioning air in the left and right direction. The up-down wind direction plate 4a is disposed downstream of the horizontal wind direction plate 4 b. The shaft portions of the vertical wind direction plate 4a provided at both ends are rotatably supported by a pair of bearings provided to the casing main body 1a with the air outlet 3 interposed therebetween. The shaft portion of the horizontal wind direction plate 4b provided at the upper portion is rotatably supported by a bearing portion provided at an upper wall 9b described later.

An air passage from the opening 2a of the suction grill 2 to the outlet 3 is formed in the center of the inside of the housing 1. The air passage is provided with a filter 5 and a heat exchanger 7, and the heat exchanger 7 transfers the heat or cold of the refrigerant to the air passing through the filter 5 to generate air-conditioning air. Further, a cross-flow fan 8 is provided in the air passage, and the cross-flow fan 8 generates a flow of air from the opening 2a toward the outlet 3.

The filter 5 is formed in a mesh shape, for example, and removes dust and the like in the air sucked through the opening 2 a. The filter 5 is disposed downstream of the suction grill 2 and upstream of the heat exchanger 7 in the air passage.

The heat exchanger 7 is a fin-tube heat exchanger including a plurality of plate-shaped fins made of aluminum arranged in parallel and a heat transfer tube penetrating the plurality of plate-shaped fins. The heat exchanger 7 constitutes a refrigeration cycle together with a compressor, an outdoor heat exchanger, an expansion device, and the like. The compressor, the outdoor heat exchanger, and the expansion device are housed in an outdoor unit, not shown. The heat exchanger 7 functions as a heat absorber, which is an evaporator, to cool air during the cooling operation, and functions as a radiator, which is a condenser, to heat air during the heating operation. In fig. 2, the heat exchanger 7 has a shape surrounding the front surface side (left side in fig. 2) and the back surface side (right side in fig. 2) of the impeller 8a, but the shape of the heat exchanger 7 is not particularly limited.

The cross flow fan 8 includes: an impeller 8a disposed in the air passage; a motor 12 (not shown in fig. 1 and 2) for driving and rotating the impeller 8 a; a stabilizer (stabilizer) 9 dividing the air passage into a suction-side air passage E1 and a discharge-side air passage E2; and a baffle wall 10 that guides the air blown out from the impeller 8a to the outlet-side air passage E2 to the outlet port 3. The impeller 8a is disposed on the downstream side of the heat exchanger 7 and on the upstream side of the outlet port 3 in the air passage. As the impeller 8a rotates, indoor air is sucked from the opening 2a and conditioned air is blown out from the air outlet 3. The impeller 8a is formed of a thermoplastic resin such AS an AS resin. Details of the impeller 8a will be described later using fig. 3 to 10.

The stabilizer 9 is formed to protrude from the front surface side of the housing main body 1a into the air passage inside the housing 1. A tongue 9a facing the impeller 8a is formed at the tip of the stabilizer 9. The tongue portion 9a extends along the rotation axis O of the impeller 8a in a direction perpendicular to the paper surface of fig. 2. The lower surface of the stabilizer 9 constitutes an upper wall 9b of the air outlet 3. A water receiving tray 9c for receiving the condensate water from the heat exchanger 7 is formed on the upper surface of the stabilizer 9.

The guide wall 10 constitutes a rear wall of the outlet air passage E2. The guide wall 10 forms a spiral slope inclined from the impeller 8a to the outlet port 3. The downstream side portion of the baffle wall 10 faces the upper wall 9b across the air outlet 3.

Fig. 3 is an external view showing the structures of the impeller 8a and the motor 12 in the indoor unit 100 of the air conditioner according to the present embodiment. In fig. 3, a front view of the impeller 8a and the motor 12 is shown together with a side view of the impeller 8 a. Fig. 4 is an external perspective view showing the structure of the impeller unit 8d in the indoor unit 100 of the air conditioner according to the present embodiment. Fig. 5 is a side view showing the structure of the impeller unit 8d in the indoor unit 100 of the air conditioner according to the present embodiment.

As shown in fig. 3 to 5, the impeller 8a has a structure in which a plurality of impeller units 8d are connected in the direction of the rotation axis O by welding or the like. Each of the plurality of impeller units 8d has a plurality of blades 8c and a support plate 8b that supports one end of each of the plurality of blades 8 c.

The plurality of blades 8c are arranged at predetermined intervals on a circumference around the rotation axis O, and each extend substantially along the rotation axis O. The plurality of blades 8c have a first end 8ca and a second end 8cb, respectively, as ends in the direction along the rotation axis O. The first end portion 8ca is supported by the outer peripheral portion of one surface of the support plate 8 b. That is, in the impeller unit 8d, the plurality of blades 8c protrude from the outer peripheral portion of one surface of the support plate 8b in a direction substantially perpendicular to the one surface. In the impeller unit 8d, the first end 8ca is an end on the root side of the blade 8c, and the second end 8cb is an end on the tip side of the blade 8 c.

Further, each of the plurality of blades 8c has an intermediate portion 8cc, and the intermediate portion 8cc is located midway between the first end portion 8ca and the second end portion 8cb in the direction along the rotation axis O. When the distance between the two adjacent support plates 8b, i.e., the distance between the first end 8ca and the second end 8cb in the direction along the rotation axis O is P, the distance between the first end 8ca and the middle 8cc in the direction along the rotation axis O is P/2.

The support plate 8b has a disc shape centered on the rotation axis O. As shown in fig. 7 to 9 described later, the support plate 8b has a radius Rr. The support plate 8b of the impeller 8a other than the two end portions in the direction of the rotation axis O may have an annular shape with the center portion thereof being open around the rotation axis O.

One end of the impeller 8a in the direction of the rotation axis O is connected to a motor 12 via a motor shaft 12 a. A fan boss 8e is provided on the support plate 8b located at the end portion. The fan boss 8e is formed to protrude toward the inside of the impeller 8a along the rotation axis O. The fan hub 8e is fixed to the motor shaft 12a with screws or the like.

An end plate 8f having a disc shape centering on the rotation axis O is provided at the other end of the impeller 8a in the rotation axis O direction. The end plate 8f has the same radius as the support plate 8 b. The end plate 8f is provided with a fan shaft 8fa extending along the rotation axis O to the outside of the impeller 8 a. The fan shaft 8fa is rotatably supported by a bearing portion provided in the case body 1 a.

When the motor 12 is energized, the driving force of the motor 12 is transmitted to the impeller 8a via the motor shaft 12 a. Thereby, the impeller 8a rotates in the rotation direction RO around the rotation axis O. By the rotation of the impeller 8a, indoor air is sucked from the opening 2a of the suction grill 2, and air-conditioning air is blown out from the air outlet 3.

Next, the shape of the blade 8c will be described in detail. Fig. 6 is an enlarged view of a VI portion of fig. 5. As shown in fig. 6, the second end 8cb of the blade 8c is disposed at a position rotationally displaced by an angle θ 2 ahead of the first end 8ca in the rotational direction RO of the impeller 8 a. Thereby, the blades 8c are inclined by an angle δ in the circumferential direction with respect to the rotation axis O (see fig. 3). That is, the blade 8c is a so-called skew blade. The intermediate portion 8cc of the blade 8c is disposed at a position forward of the first end portion 8ca by a rotational displacement angle θ 1(θ 1 — θ 2/2) in the rotational direction RO of the impeller 8 a.

When the blades are not tilted with respect to the rotation axis, the timing of passing the tongue portion that separates the suction-side air passage and the discharge-side air passage is set to be the same at each position in the rotation axis direction of the blades. In contrast, in the present embodiment, the blade 8c is inclined with respect to the rotation axis O, and therefore the timing at which the tongue 9a passes through each position of the blade 8c in the rotation axis O direction is shifted. Therefore, in the present embodiment, the rotational noise of the cross flow fan 8 can be reduced.

The vane 8c has an inner peripheral end 8h positioned on the inner peripheral side of the impeller unit 8d and an outer peripheral end 8g positioned on the outer peripheral side of the impeller unit 8d as ends in the radial direction around the rotation axis O. The pressure surface 8j, which is a side surface of the blade 8c on the rotation direction RO side, is curved toward the rotation direction RO side from the inner circumferential end 8h toward the outer circumferential end 8 g. Similarly, the negative pressure surface 8k, which is the side surface of the blade 8c on the opposite side to the rotation direction RO, is curved toward the rotation direction RO from the inner circumferential end 8h toward the outer circumferential end 8 g. Thereby, the vane 8c is curved so that the pressure surface 8j side is concave and the suction surface 8k side is convex.

Here, the center of the inner circumferential end 8h of the blade 8c in the cross section perpendicular to the rotation axis O is 8hm, and the angle formed by two line segments connecting the centers 8hm of the two adjacent blades 8c and the rotation axis O is a pitch angle (see fig. 5). At this time, the pitch angle α 1 between any two blades 8c is different from the pitch angle α 2 between any two other blades 8c (α 1 ≠ α 2). That is, the plurality of blades 8c are not all equally-spaced blades having a uniform pitch angle, but are non-equally-spaced blades having at least two different pitch angles. Thus, since the periodic pressure fluctuation when each vane 8c approaches the tongue portion 9a or the baffle wall 10 can be alleviated, the NZ sound, which is the peak rotational sound, can be suppressed, and the indoor unit 100 of the air conditioner having high quietness can be obtained.

Fig. 7 is a sectional view showing a part of the section VII-VII of fig. 3. Fig. 8 is a sectional view showing a part of the section VIII-VIII of fig. 3. Fig. 9 is a sectional view showing a part of the section IX-IX of fig. 3. Fig. 7, 8, and 9 show cross sections obtained by cutting the first end portion 8ca, the second end portion 8cb, and the middle portion 8cc of one blade 8c on a plane perpendicular to the rotation axis O. In fig. 7 to 9, cross-sectional hatchings of the first end portion 8ca, the second end portion 8cb, and the intermediate portion 8cc are omitted in order to prevent the drawings from becoming complicated.

In the description relating to fig. 7 to 9, as a principle, common reference numerals are used for the common structure and dimensions in the first end portion 8ca, the second end portion 8cb, and the intermediate portion 8 cc. However, in order to distinguish the configuration and the size of each of the first end portion 8ca, the second end portion 8cb, and the intermediate portion 8cc, individual reference numerals in which "a", "b", and "c" are respectively added to common reference numerals may be used. In fig. 7 to 9, common reference numerals for some are denoted by individual reference numerals in parentheses.

As shown in fig. 7 to 9, the cross-sectional area of the second end portion 8cb in a cross section perpendicular to the rotation axis O is smaller than the cross-sectional area of the first end portion 8ca in a cross section perpendicular to the rotation axis O. The cross-sectional area of the middle portion 8cc in a cross-section perpendicular to the rotation axis O is larger than the cross-sectional area of the second end portion 8cb and smaller than the cross-sectional area of the first end portion 8 ca. That is, the cross-sectional area of the blade 8c in the cross-section perpendicular to the rotation axis O gradually decreases from the first end 8ca toward the second end 8 cb. Therefore, the blade 8c has a shape that becomes tapered from the first end 8ca toward the second end 8cb in the direction substantially along the rotation axis O.

The distance Rtb between the rotation axis O and the outer circumferential end 8gb of the second end 8cb is shorter than the distance Rta between the rotation axis O and the outer circumferential end 8ga of the first end 8ca (Rtb < Rta). The distance Rtc between the rotation axis O and the outer peripheral side end portion 8gc in the intermediate portion 8cc is longer than the distance Rtb and shorter than the distance Rta (Rtb < Rtc < Rta). That is, the distance between the rotation axis O and the outer circumferential end 8g gradually decreases from the first end 8ca toward the second end 8 cb. Here, the distance Rt between the rotation axis O and the outer peripheral end 8g is defined as the radius of a circumscribed circle that contacts the outer peripheral end 8g about the rotation axis O in a cross section perpendicular to the rotation axis O.

The distance Rib between the rotation axis O and the inner circumferential end 8hb of the second end 8cb is longer than the distance Ria between the rotation axis O and the inner circumferential end 8ha of the first end 8ca (Rib > Ria). The distance Ric between the rotation axis O and the inner peripheral side end 8hc of the intermediate portion 8cc is shorter than the distance Rib and longer than the distance Ria (Rib > Ric > Ria). That is, the distance between the rotation axis O and the inner circumferential end 8h gradually increases from the first end 8ca toward the second end 8 cb. Here, the distance Ri between the rotation axis O and the inner peripheral end 8h is defined as the radius of an inscribed circle that touches the inner peripheral end 8h with the rotation axis O as the center.

Here, the blade chord line Lo and the blade chord length L will be described. The blade chord line Lo is defined as a straight line that meets both the contour of the inner peripheral end 8h and the contour of the outer peripheral end 8g in a cross section perpendicular to the rotation axis O. The blade chord length L is defined as the length of the blade 8c in the direction along the blade chord line Lo. That is, the blade chord length L is equal to the distance between a straight line perpendicular to the blade chord Lo and contacting the contour of the inner peripheral end 8h and a straight line perpendicular to the blade chord Lo and contacting the contour of the outer peripheral end 8 g. The blade chord length Lb of the second end portion 8cb is shorter than the blade chord length La of the first end portion 8ca (Lb < La). The blade chord length Lc of the intermediate portion 8cc is longer than the blade chord length Lb of the second end portion 8cb and shorter than the blade chord length La of the first end portion 8ca (Lb < Lc < La). That is, the blade chord length L gradually decreases from the first end portion 8ca toward the second end portion 8 cb.

In each of the cross-sections shown in fig. 7 to 9, the contour of the inner circumferential end 8h is formed by one arc of substantially half the circumference around the center 8 hm. One end of the arc is connected to the inner peripheral end of the pressure surface 8j, and the other end of the arc is connected to the inner peripheral end of the negative pressure surface 8 k. The wall thickness of the inner peripheral end 8h is t 1. The contour of the outer peripheral end 8g is formed by a single arc of substantially half a circumference centered on the center 8 gm. One end of the arc is connected to the outer peripheral end of the pressure surface 8j, and the other end of the arc is connected to the outer peripheral end of the negative pressure surface 8 k. The outer peripheral end 8g has a wall thickness t 2. In each cross section, when the thickness t1 of the inner peripheral end 8h is compared with the thickness t2 of the outer peripheral end 8g, the thickness t1 is larger than the thickness t2(t1 > t2, t1a > t2a, t1b > t2b, and t1c > t2 c). Further, since the blade 8c has a tapered shape, the wall thickness t1 of the inner circumferential side end portion 8h becomes gradually smaller from the first end portion 8ca toward the second end portion 8cb (t1a > t1c > t1 b). Similarly, the wall thickness t2 of the outer peripheral end 8g gradually decreases from the first end 8ca toward the second end 8cb (t2a > t2c > t2 b).

Here, the thickness t1 of the inner peripheral end 8h is defined as the diameter of an inscribed circle that contacts the contour line of the inner peripheral end 8h, the pressure surface 8j, and the negative pressure surface 8k in a cross section perpendicular to the rotation axis O. The thickness t2 of the outer peripheral end 8g is defined as the diameter of an inscribed circle that contacts the contour line of the outer peripheral end 8g, the pressure surface 8j, and the negative pressure surface 8k in a cross section perpendicular to the rotation axis O. The thickness of the other portion of the blade 8c is defined as the diameter of an inscribed circle that meets the pressure surface 8j and the negative pressure surface 8k in a cross section perpendicular to the rotation axis O.

In each of the cross sections shown in fig. 7 to 9, the blade 8c has a maximum thickness portion TM whose thickness (i.e., the diameter of an inscribed circle that contacts the pressure surface 8j and the negative pressure surface 8 k) is maximum. The maximum wall thickness portion TM is located closer to the inner circumferential end portion 8h than a straight line Lo3 that passes through the midpoint Lo2 of the blade chord line Lo and is perpendicular to the blade chord line Lo. Further, the maximum thickness portion TM is located on the outer peripheral side of the inner peripheral side end portion 8 h. In each of the cross sections shown in fig. 7 to 9, the thickness of the blade 8c gradually decreases from the maximum thickness portion TM toward the inner peripheral side end portion 8h and gradually decreases from the maximum thickness portion TM toward the outer peripheral side end portion 8 g. The wall thickness of the maximum thickness portion TMa at the first end portion 8ca is tmaxa, the wall thickness of the maximum thickness portion TMb at the second end portion 8cb is tmaxb, and the wall thickness of the maximum thickness portion TMc at the intermediate portion 8cc is tmaxc. Since the blade 8c has a tapered shape, the wall thickness of the maximum wall thickness portion TM gradually becomes smaller from the first end portion 8ca toward the second end portion 8cb (tmaxa > tmaxc > tmaxb).

For example, in the second end portion 8cb, the wall thickness t1b of the inner circumference side end portion 8hb is 0.60mm, the wall thickness t2b of the outer circumference side end portion 8gb is 0.50mm, and the wall thickness tmaxb of the maximum wall thickness portion TMb is 0.62 mm.

In the cross section shown in fig. 7, when the center of the inscribed circle contacting the outer peripheral end 8ga, the pressure surface 8ja, and the negative pressure surface 8ka is set to 8gma, the distance between the center 8gma and the rotation axis O is Rga. In the cross section shown in fig. 8, when the center of an inscribed circle contacting the outer peripheral end 8gb, the pressure surface 8jb, and the negative pressure surface 8kb is set to 8gmb, the distance between the center 8gmb and the rotation axis O is Rgb. In the cross section shown in fig. 9, when the center of the inscribed circle contacting the outer peripheral end 8gc, the pressure surface 8jc, and the negative pressure surface 8kc is set to 8gmc, the distance between the center 8gmc and the rotation axis O is Rgc. Distance Rga, distance Rgb, and distance Rgc are equal (Rga Rgb Rgc). The distance Rga, the distance Rgb, and the distance Rgc may be collectively referred to as a distance Rg (Rga Rgb, Rgc, Rg).

In the cross section shown in fig. 7, when the center of an inscribed circle contacting the inner peripheral end 8ha, the pressure surface 8ja, and the suction surface 8ka is 8hma, the distance between the center 8hma and the rotation axis O is Rha. In the cross section shown in fig. 8, when the center of an inscribed circle contacting the inner peripheral end 8hb, the pressure surface 8jb, and the negative pressure surface 8kb is set to 8hmb, the distance between the center 8hmb and the rotation axis O is Rhb. In the cross section shown in fig. 9, when the center of an inscribed circle contacting the inner peripheral end 8hc, the pressure surface 8jc, and the negative pressure surface 8kc is set to 8hmc, the distance between the center 8hmc and the rotation axis O is Rhc. The distance Rha, the distance Rhb, and the distance Rhc are equal (Rha ═ Rhb ═ Rhc). The distance Rha, the distance Rhb, and the distance Rhc may be collectively referred to as a distance Rh (Rha ═ Rhb ═ Rhc ═ Rh). In addition, the distance between the center 8hma and the center 8gma in the cross section shown in fig. 7, the distance between the center 8hmb and the center 8gmb in the cross section shown in fig. 8, and the distance between the center 8hmc and the center 8gmc in the cross section shown in fig. 9 are equal.

In the cross section shown in fig. 7, when the center of the inscribed circle that contacts the pressure surface 8ja and the negative pressure surface 8ka at the maximum thickness portion TMa is TMma, the distance between the center TMma and the rotation axis O is Rma. The distance Rma is longer than the distance Rha and shorter than the distance Rga (Rha < Rma < Rga). In the cross section shown in fig. 8, when the center of the inscribed circle that contacts the pressure surface 8jb and the negative pressure surface 8kb at the maximum thickness portion TMb is TMmb, the distance between the center TMmb and the rotation axis O is Rmb. Distance Rmb is longer than distance Rhb and shorter than distance Rgb (Rhb < Rmb < Rgb). In the cross section shown in fig. 9, when the center of the inscribed circle that contacts the pressure surface 8jc and the negative pressure surface 8kc at the maximum thickness portion TMc is TMmc, the distance between the center TMmc and the rotation axis O is Rmc. Distance Rmc is longer than distance Rhc and shorter than distance Rgc (Rhc < Rmc < Rgc). The distance Rma, the distance Rmb, and the distance Rmc are equal (Rma Rmb Rmc). The distance Rma, the distance Rmb, and the distance Rmc may be collectively referred to as a distance Rm (Rma-Rmb-Rmc-Rm). In addition, the distance between the center 8hma and the center TMma in the cross section shown in fig. 7, the distance between the center 8hmb and the center TMmb in the cross section shown in fig. 8, and the distance between the center 8hmc and the center TMmc in the cross section shown in fig. 9 are equal. Further, the distance between the center 8gma and the center TMma in the cross section shown in fig. 7, the distance between the center 8gmb and the center TMmb in the cross section shown in fig. 8, and the distance between the center 8gmc and the center TMmc in the cross section shown in fig. 9 are equal.

A distance Rta between the rotation axis O and the outer circumferential end 8ga of the first end 8ca, a distance Rtb between the rotation axis O and the outer circumferential end 8gb of the second end 8cb, a distance Ria between the rotation axis O and the inner circumferential end 8ha of the first end 8ca, a distance Rib between the rotation axis O and the inner circumferential end 8hb of the second end 8cb, and a distance P between the first end 8ca and the second end 8cb in the direction along the rotation axis O satisfy the following relationships.

(Rta－Rtb)/P＝(Rib－Ria)/P

Fig. 10 is a diagram showing a virtual state in which the cross sections of the first end portion 8ca, the second end portion 8cb, and the middle portion 8cc of the impeller unit 8d of the indoor unit 100 of the air conditioner according to the present embodiment are superimposed on the same plane such that the centers 8gma, 8gmb, and 8gmc coincide with each other, and the centers 8hma, 8hmb, and 8hmc coincide with each other. Fig. 10 is obtained by superimposing the cross section of the first end portion 8ca shown in fig. 7, the cross section of the second end portion 8cb shown in fig. 8, and the cross section of the intermediate portion 8cc shown in fig. 9 while rotating relative to each other about the rotation axis O in the drawing. In fig. 10, the centers TMma, TMmb, and TMmc of the maximum wall thickness portion TM of each section are also coincident.

As shown in fig. 10, the distance Δ Le between the contour line of the cross section of the first end 8ca and the contour line of the cross section of the second end 8cb is constant over the entire circumference of the blade 8 c. Further, the distance Δ lec between the contour line of the cross section of the first end portion 8ca and the contour line of the cross section of the intermediate portion 8cc is constant over the entire circumference of the blade 8c, and the distance Δ Lebc between the contour line of the cross section of the intermediate portion 8cc and the contour line of the cross section of the second end portion 8cb is constant over the entire circumference of the blade 8 c. The distance Δ lec and the distance Δ Lebc are both equal to half the distance Δ Le (Δ lec ═ Δ Lebc ═ Δ Le/2).

The pressure surface 8j in each cross section has a first straight line portion 8Lj adjacent to the inner peripheral side end portion 8 h. The negative pressure surface 8k in each cross section has a second linear portion 8Lk adjacent to the inner peripheral end portion 8 h.

Specifically, the pressure surface 8ja in the cross section shown in fig. 7 includes a first curved portion 8Cja formed of a curved line having a concave portion on the pressure surface 8ja side and a first straight portion 8Lja formed of a straight line. One end of the first curved portion 8Cja is connected to the pressure surface side end of the arc constituting the contour of the outer peripheral end 8 ga. The other end of the first curved portion 8Cja is connected to one end of the first linear portion 8 Lja. The other end of the first straight line portion 8Lja is connected to the pressure surface side end portion of the arc constituting the contour of the inner circumference side end portion 8 ha. The first curved portion 8Cja is a multiple circular arc curve composed of 2 or more circular arcs having different radii. The radius Rja1 of the arc on the outer peripheral end 8ga side is larger than the radius Rja2 of the arc on the inner peripheral end 8ha side.

The negative pressure surface 8ka has a second curved portion 8Cka formed by a curved line having a convex side on the negative pressure surface 8ka and a second linear portion 8Lka formed by a straight line. One end of the second curved portion 8Cka is connected to the end of the suction surface of the arc constituting the contour of the outer peripheral end 8 ga. The other end of the second curved portion 8Cka is connected to one end of the second linear portion 8 Lka. The other end of the second linear portion 8Lka is connected to a negative pressure surface side end portion of an arc constituting the contour of the inner peripheral side end portion 8 ha. The second straight line portion 8Lka is parallel to the first straight line portion 8 Lja. The second curved portion 8Cka is a multiple circular arc curve composed of 2 or more circular arcs having different radii. The radius Rka1 of the arc on the outer peripheral end 8ga side is larger than the radius Rka2 of the arc on the inner peripheral end 8ha side.

The pressure surface 8jb in the cross section shown in fig. 8 has a first curved portion 8Cjb formed of a curved line whose pressure surface 8jb side is concave and a first straight portion 8Ljb formed of a straight line. One end of the first curved portion 8Cjb is connected to the pressure surface side end of the arc constituting the outline of the outer peripheral end 8 gb. The other end of the first curved portion 8Cjb is connected to one end of the first linear portion 8 Ljb. The other end of the first straight line portion 8Ljb is connected to the pressure surface side end portion of the arc constituting the contour of the inner peripheral side end portion 8 hb. The first curved portion 8Cjb is a multiple circular arc curve composed of 2 or more circular arcs having different radii. The radius Rjb1 of the arc on the outer circumferential end 8gb side is larger than the radius Rjb2 of the arc on the inner circumferential end 8hb side.

The negative pressure surface 8kb has a second curved portion 8 cbb formed by a curved line convex toward the negative pressure surface 8kb and a second straight portion 8Lkb formed by a straight line. One end of the second curved portion 8Ckb is connected to the negative pressure surface side end of the arc constituting the contour of the outer peripheral end 8 gb. The other end of the second curved portion 8 cbb is connected to one end of the second linear portion 8 Lkb. The other end of the second linear portion 8Lkb is connected to the negative pressure surface side end of the arc constituting the contour of the inner peripheral end 8 hb. The second linear portion 8Lkb is parallel to the first linear portion 8 Ljb. The second curved portion 8 cbb is a multiple circular arc curve composed of 2 or more circular arcs having different radii. The radius Rkb1 of the arc on the outer circumferential end 8gb side is larger than the radius Rkb2 of the arc on the inner circumferential end 8hb side.

The pressure surface 8jc in the cross section shown in fig. 9 has a first curved portion 8Cjc formed of a curved line whose pressure surface 8jc side is concave and a first straight portion 8Ljc formed of a straight line. One end of the first curved portion 8Cjc is connected to the pressure surface side end of the arc constituting the outline of the outer peripheral end 8 gc. The other end of the first curved portion 8Cjc is connected to one end of the first linear portion 8 Ljc. The other end of the first straight line portion 8Ljc is connected to the pressure surface side end portion of the arc constituting the contour of the inner peripheral side end portion 8 hc. The first curved portion 8Cjc is a multiple circular arc curve composed of 2 or more circular arcs having different radii. The radius Rjc1 of the arc on the outer peripheral end 8gc side is larger than the radius Rjc2 of the arc on the inner peripheral end 8hc side.

The suction surface 8kc has a second curved portion 8Ckc formed by a curved line convex toward the suction surface 8kc and a second linear portion 8Lkc formed by a straight line. One end of the second curved portion 8Ckc is connected to the suction surface side end of the arc constituting the outline of the outer peripheral end 8 gc. The other end of the second curved portion 8Ckc is connected to one end of the second linear portion 8 Lkc. The other end of the second linear portion 8Lkc is connected to the negative pressure surface side end of the arc constituting the contour of the inner peripheral end 8 hc. The second linear portion 8Lkc is parallel to the first linear portion 8 Ljc. The second curved portion 8Ckc is a multiple circular arc curve composed of 2 or more circular arcs having different radii. The radius Rkc1 of the arc on the outer circumferential end 8gc side is larger than the radius Rkc2 of the arc on the inner circumferential end 8hc side.

Since the second linear portions 8Lka, 8Lkb, and 8Lkc are parallel to the first linear portions 8Lja, 8Ljb, and 8Ljc, respectively, a flat plate portion is formed on the inner circumferential end 8h side of the blade 8 c. The flat plate portion has a constant thickness in a cross section perpendicular to the rotation axis O.

In each of the cross sections shown in fig. 7 to 9, the blade 8c has maximum warping portions having maximum warping heights has, hsb, and hsc on the inner circumferential side end 8h side of the straight line Lo 3. Here, the maximum buckling height is defined as the maximum value among the distances from the blade chord line Lo to the negative pressure surface 8 k. A distance Ls from the inner peripheral side end 8h to the maximum warping portion in the direction along the blade chord Lo is shorter than half of the blade chord L (Ls < L/2).

Fig. 11 is a graph showing a relationship between a rotational displacement angle ratio a of the vane 8c and a motor input ratio in the cross flow fan 8 of the indoor unit 100 of the air conditioner according to the present embodiment. The horizontal axis of the graph represents the rotational displacement angle ratio a [ deg/mm ] of the blade 8c, and the vertical axis represents the motor input ratio (%) of the crossflow fan 8. Here, the disclination angle ratio A is expressed in terms of θ 2/P [ deg/mm ]. θ 2[ deg ] is a rotational displacement angle of the second end portion 8cb with respect to the first end portion 8ca around the rotation axis O (see fig. 6). P [ mm ] is the distance between the first end 8ca and the second end 8cb in the direction along the rotation axis O (see fig. 3).

As shown in FIG. 11, it is understood that when the angular rotational displacement ratio A of the vane 8c satisfies the relationship of 0.02[ deg/mm ] ≦ A ≦ 0.05[ deg/mm ], the motor input ratio can be reduced as compared with the other cases.

Fig. 12 is a graph showing a relationship between tmax/L and a motor input ratio in the cross flow fan 8 of the indoor unit 100 of the air conditioner according to the present embodiment. The horizontal axis of the graph indicates tmax/L, and the vertical axis indicates the motor input ratio (%) of the cross flow fan 8. Here, tmax [ mm ] is the thickness of the maximum thickness portion TM of the blade 8c in the cross section perpendicular to the rotation axis O (see fig. 7 to 9). L [ mm ] is a blade chord length of the blade 8c in the cross section (see FIGS. 7 to 9).

As shown in FIG. 12, it is understood that tmax/L satisfies the relationship of 0.045. ltoreq. tmax/L. ltoreq.0.080 to reduce the motor input ratio. However, even when tmax/L satisfies the relationship of 0.045 ≦ tmax/L ≦ 0.080, there are cases where a reduction effect with a high motor input ratio can be obtained (points indicated by a box in the graph) and where a reduction effect with a high motor input ratio cannot be obtained (points indicated by a circle in the graph).

FIG. 13 is a graph showing the relationship of tmax/t2 and the motor input ratio in the crossflow fan 8 satisfying the relationship of 0.045. ltoreq. tmax/L. ltoreq.0.080. The horizontal axis of the graph indicates tmax/t2, and the vertical axis indicates the motor input ratio (%) of the cross flow fan 8. Here, tmax [ mm ] is the thickness of the maximum thickness portion TM of the blade 8c in the cross section perpendicular to the rotation axis O (see fig. 7 to 9). t2[ mm ] is the thickness of the outer peripheral end 8g of the blade 8c in the cross section (see fig. 7 to 9).

As shown in fig. 13, it is understood that when tmax/t2 satisfies the relationship of 1.1. ltoreq. tmax/t 2. ltoreq.2.0, the motor input ratio can be reduced as compared with the other cases. That is, as can be seen from fig. 12 and 13: when tmax/L satisfies the relationship of 0.045. ltoreq. tmax/L. ltoreq.0.080 and tmax/t2 satisfies the relationship of 1.1. ltoreq. tmax/t 2. ltoreq.2.0, a reduction effect of high motor input ratio can be obtained. Preferably, the above-mentioned relationship is satisfied in both the cross section of the first end portion 8ca and the cross section of the second end portion 8 cb.

Fig. 14 is a graph showing a relationship between P/(2 × Rt) and a motor input ratio in the cross flow fan 8 of the indoor unit 100 of the air conditioner according to the present embodiment. The horizontal axis of the graph represents P/(2 × Rt), and the vertical axis represents the motor input ratio (%) of the cross flow fan 8. Here, P [ mm ] is a distance between the first end 8ca and the second end 8cb in the direction along the rotation axis O (see fig. 3). Rt [ mm ] is the distance between the rotation axis O and the outer peripheral end 8g in a cross section perpendicular to the rotation axis O (see fig. 7 to 9). As described above, since the distance Rt is defined as the radius of a circumscribed circle that meets the outer peripheral side end portion 8g around the rotation axis O in a cross section perpendicular to the rotation axis O, (2 × Rt) is equal to the diameter of a circumscribed circle that meets the outer peripheral side end portion 8g around the rotation axis O in a cross section perpendicular to the rotation axis O.

As shown in fig. 14, it is understood that when P/(2 × Rt) satisfies the relationship of 0.45 ≦ P/(2 × Rt) ≦ 0.80, the motor input ratio can be reduced as compared with the other cases. Preferably, the above-mentioned relationship is satisfied in both the cross section of the first end portion 8ca and the cross section of the second end portion 8 cb.

As described above, the indoor unit 100 of the air conditioner according to the present embodiment includes: a casing 1 having an opening 2a and an outlet 3; and a cross flow fan 8 housed in the casing 1. The cross flow fan 8 includes: an impeller 8a disposed in an air passage formed in the casing 1; a stabilizer 9 dividing the air passage into a suction-side air passage E1 and a discharge-side air passage E2; and a baffle wall 10 that guides the air blown out from the impeller 8a to the outlet-side air passage E2 to the outlet port 3. The impeller 8a has: a plurality of blades 8c each disposed on a circumference around the rotation axis O of the impeller 8a and having a first end 8ca and a second end 8cb as ends along the rotation axis O; and a support plate 8b that supports the first end portions 8ca of the plurality of blades 8 c. The second end portion 8cb is disposed ahead of the first end portion 8ca in the rotation direction RO of the impeller 8 a. Each of the plurality of blades 8c has an inner peripheral end 8h and an outer peripheral end 8g as radial ends about the rotation axis O. The cross-sectional area of the second end portion 8cb in a cross-section perpendicular to the rotation axis O is smaller than the cross-sectional area of the first end portion 8ca in a cross-section perpendicular to the rotation axis O. The distance Rtb between the rotation axis O and the outer circumferential side end 8g at the second end 8cb is shorter than the distance Rta between the rotation axis O and the outer circumferential side end 8g at the first end 8 ca. The distance Rib between the rotation axis O and the inner circumferential end 8h at the second end 8cb is longer than the distance Ria between the rotation axis O and the inner circumferential end 8h at the first end 8 ca. In a cross section perpendicular to the rotation axis O, the thickness t1 of the inner circumferential end 8h is larger than the thickness t2 of the outer circumferential end 8 g. In a cross section perpendicular to the rotation axis O, each of the plurality of blades 8c has a maximum thickness portion TM having a maximum thickness on the inner circumferential end 8h side of a straight line Lo3 passing through a midpoint Lo2 of a blade chord line Lo of each of the plurality of blades 8c and perpendicular to the blade chord line Lo. Here, the opening 2a is an example of the suction port.

A minimum gap between the outer circumferential end 8G of the blade 8c and the tongue 9a of the stabilizer 9 is a fan gap G1, and a minimum gap between the outer circumferential end 8G of the blade 8c and the baffle wall 10 is a fan gap G2 (see fig. 2). In the present embodiment, the fan gaps G1 and G2 are each gradually enlarged from the first end 8ca toward the second end 8cb of the blade 8 c. In the first end 8ca, since the fan gaps G1 and G2 are relatively narrow, the flow of air rapidly fluctuates in the outlet-side air passage E2 from the inlet-side air passage E1. However, in the present embodiment, since the first end portion 8ca is relatively thick with respect to the second end portion 8cb, even if an angle change due to a fluctuation in the flow of air occurs, peeling is less likely to occur. On the other hand, in the second end 8cb, the fan gaps G1 and G2 are relatively widened. Therefore, although the second end portion 8cb is relatively thin, the variation in the flow of air in the outlet-side air passage E2 from the inlet-side air passage E1 is relatively small in the second end portion 8cb, and therefore peeling is less likely to occur. Therefore, according to the present embodiment, since the generation of vortices caused by the separation can be suppressed, the effective passage area when the air passes between the adjacent blades 8c can be increased, and the efficiency of the cross flow fan 8 can be improved.

The distance between adjacent blades 8c is smaller on the thick first end 8ca side than on the thin second end 8cb side. The blade chord La of the first end portion 8ca is longer than the blade chord Lb of the second end portion 8 cb. Thereby, the inter-blade distance gradually increases from the first end portion 8ca toward the second end portion 8 cb. The inter-blade passage wind speed gradually decreases from the first end portion 8ca toward the second end portion 8 cb. Therefore, a pressure gradient can be generated in the direction from the first end portion 8ca toward the second end portion 8 cb. Therefore, according to the present embodiment, even if the flow of air becomes unstable on the first end portion 8ca side, the flow can be suppressed by the pressure gradient, so that the flow can be maintained stable.

On the suction side of the impeller 8a, air flows from the outer circumferential end 8g toward the inner circumferential end 8h of the blade 8 c. In the present embodiment, since the maximum thickness portion TM is formed on the inner peripheral side of the blade 8c, even if the flow of air tries to peel off from the blade surface on the outer peripheral side of the blade 8c, the peeling can be suppressed by the maximum thickness portion TM of the blade 8c whose inter-blade distance is reduced. On the other hand, on the blowing side of the impeller 8a, air flows from the inner circumferential end 8h to the outer circumferential end 8g of the blade 8 c. On the outlet side of the impeller 8a, the inflow angle of air to the blades 8c is more likely to change than on the inlet side of the impeller 8a due to the flow fluctuation. In the present embodiment, since the thickness t1 of the inner circumferential end 8h serving as the leading edge is larger than the thickness t2 of the outer circumferential end 8g, the occurrence of separation can be suppressed even if the inflow angle of air changes. Therefore, according to the present embodiment, since the generation of vortices caused by the separation can be suppressed, the effective passage area between the adjacent blades 8c can be increased, and the efficiency of the cross flow fan 8 can be improved.

In the present embodiment, the inner circumferential end 8h of the blade 8c is relatively thick, and the blade 8c is inclined with respect to the rotation axis O. Therefore, even if the flow tries to peel off in a partial region of the blade surface due to the angle difference between the air flow and the blade surface of the blade 8c on the blowing side of the impeller 8a, the flow can be mixed with another flow that flows into the partial region at a shifted timing, thereby suppressing the peeling. Therefore, the rotation sound of the cross flow fan 8 can be reduced. In addition, since the effective passage area between the adjacent blades 8c can be increased, the efficiency of the cross flow fan 8 can be improved.

In the present embodiment, since the blades 8c are inclined with respect to the rotation axis O, even if flow separation occurs at the outer peripheral end portion 8g on the suction side of the impeller 8a after passing through the tongue portion 9a, a part of the vortex generated by the separation moves to the downstream side, that is, the first end portion 8ca side, in accordance with the inclination of the blades 8 c. This makes it possible to reduce the thickness of the vortex on the blade surface, since the shape of the vortex can be made thinner along the blade surface of the blade 8 c. Therefore, the effective passage area between the adjacent blades 8c can be increased, and the efficiency of the crossflow fan 8 can be improved.

As described above, according to the present embodiment, the efficiency of the cross flow fan 8 can be improved and the rotational noise of the cross flow fan 8 can be reduced. Therefore, the indoor unit 100 of the air conditioner having excellent energy saving performance and high quality can be obtained.

In the indoor unit 100 of an air conditioner according to the present embodiment, a cross section perpendicular to the rotation axis O in the first end 8ca is a first cross section of each of the plurality of blades 8c, and a cross section perpendicular to the rotation axis O in the second end 8cb is a second cross section of each of the plurality of blades 8 c. In the first cross section, an inscribed circle in contact with the outer peripheral side end 8ga, the pressure surface 8ja, and the negative pressure surface 8ka is defined as a first inscribed circle, and in the second cross section, an inscribed circle in contact with the outer peripheral side end 8gb, the pressure surface 8jb, and the negative pressure surface 8kb is defined as a second inscribed circle. In the first cross section, an inscribed circle in contact with the inner peripheral end portion 8ha, the pressure surface 8ja, and the negative pressure surface 8ka is defined as a third inscribed circle, and in the second cross section, an inscribed circle in contact with the inner peripheral end portion 8hb, the pressure surface 8jb, and the negative pressure surface 8kb is defined as a fourth inscribed circle. At this time, a distance Rga between the rotation axis O and the center 8gma of the first inscribed circle and a distance Rgb between the rotation axis O and the center 8gmb of the second inscribed circle are equal. Further, the distance Rha between the rotation axis O and the center 8hma of the third inscribed circle and the distance Rhb between the rotation axis O and the center 8hmb of the fourth inscribed circle are equal.

According to this configuration, since the shape of the blade 8c is not greatly deformed, the difference in flow between the cross sections perpendicular to the rotation axis O is small. Therefore, since local separation or disturbance is less likely to occur at each position in the direction of the rotation axis O of the blade 8c, the efficiency of the cross flow fan 8 can be improved.

In the cross-flow fan described in patent document 1, the cross-sectional center of the blade is displaced from the root toward the tip to the outside in the radial direction of the impeller. In such a cross flow fan, a centrifugal force applied to the tip of the blade is larger than a centrifugal force applied to the root of the blade. This may cause deformation of the blade due to load variation, which may increase noise of the cross flow fan and reduce efficiency. In contrast, in the present embodiment, the distance between the rotation axis O and the center 8gm of the outer circumferential end 8g and the distance between the rotation axis O and the center 8hm of the inner circumferential end 8h are constant between the first end 8ca and the second end 8 cb. Therefore, since the deformation of the blade 8c due to the load variation can be suppressed, the noise reduction and the efficiency improvement of the cross flow fan 8 can be achieved.

In the indoor unit 100 of an air conditioner according to the present embodiment, an inscribed circle in which the maximum thickness portion TMa in the first cross section meets the pressure surface 8ja and the negative pressure surface 8ka is defined as a fifth inscribed circle, and an inscribed circle in which the maximum thickness portion TMb in the second cross section meets the pressure surface 8jb and the negative pressure surface 8kb is defined as a sixth inscribed circle. At this time, a distance Rma between the rotation axis O and the center TMma of the fifth inscribed circle and a distance Rmb between the rotation axis O and the center TMmb of the sixth inscribed circle are equal.

According to this configuration, since the blades 8c are less likely to twist when the plurality of impeller units 8d are coupled in the direction of the rotation axis O, the workability of assembling the impeller 8a is improved.

In the indoor unit 100 of an air conditioner according to the present embodiment, when the first cross section and the second cross section are superimposed on each other on the same plane such that the center 8gma of the first inscribed circle coincides with the center 8gmb of the second inscribed circle and the center 8hma of the third inscribed circle coincides with the center 8hmb of the fourth inscribed circle, the distance Δ Le between the contour line of the first cross section and the contour line of the second cross section is constant over the entire circumference of each of the plurality of blades.

In the indoor unit 100 of an air conditioner according to the present embodiment, when the distance between the rotation axis O and the outer circumferential end 8ga at the first end 8ca is Rta, the distance between the rotation axis O and the outer circumferential end 8gb at the second end 8cb is Rtb, the distance between the rotation axis O and the inner circumferential end 8ha at the first end 8ca is Ria, the distance between the rotation axis O and the inner circumferential end 8hb at the second end 8cb is Rib, and the distance between the first end 8ca and the second end 8cb in the direction along the rotation axis O is P,

satisfies the relationship of (Rta-Rtb)/P ═ Rib-Ria)/P.

According to these configurations, the distance Δ Le can be made constant over the entire circumference of the blade 8c, and the rate of change in the distance between the rotation axis O and the outer circumferential end 8g in the direction of the rotation axis O and the rate of change in the distance between the rotation axis O and the inner circumferential end 8h in the direction of the rotation axis O can be made constant. Therefore, since the flow does not become unstable at each position in the direction of the rotation axis O of the blade 8c and separation or disturbance is less likely to occur, the efficiency of the crossflow fan 8 can be improved. This makes it possible to obtain an indoor unit 100 of an air conditioner having excellent energy saving performance.

In the indoor unit 100 of an air conditioner according to the present embodiment, when the rotational displacement angle of the second end 8cb with respect to the first end 8ca about the rotation axis O is θ 2[ deg ], and the distance between the first end 8ca and the second end 8cb in the direction along the rotation axis O is P [ mm ],

satisfies the relation of theta 2/P being more than or equal to 0.02[ deg/mm ] and less than or equal to 0.05[ deg/mm ].

If θ 2/P is too small, the effect as a diagonal blade becomes small. On the other hand, if θ 2/P is too large, a flow along the leading edge of the blade 8c is generated in each blade 8c from the second end 8cb located forward in the rotational direction toward the first end 8ca located rearward. This causes the flow to converge toward the first end 8ca, and a wind speed distribution to be formed in the direction along the rotation axis O, which leads to noise increase and separation.

When θ 2/P satisfies the above relationship, the blowing direction is a direction substantially perpendicular to the rotation axis O. Therefore, even if the load varies, it is difficult to form a wind speed distribution in which the wind speed locally decreases at the end portion in the rotation axis O direction in the outlet port 3 of the indoor unit 100. Therefore, since the variation in the blowing characteristics due to the variation in the load can be suppressed, the noise of the cross flow fan 8 can be reduced, and the efficiency of the cross flow fan 8 can be improved. Therefore, the indoor unit 100 of the air conditioner having high quality and excellent energy saving performance can be obtained.

In the indoor unit 100 of an air conditioner according to the present embodiment, when the blade chord length of each of the plurality of blades 8c is L, the wall thickness of the outer circumferential end portion 8g is t2, and the wall thickness of the maximum wall thickness portion TM is tmax in the cross section perpendicular to the rotation axis O,

satisfies the relation of 0.045-tmax/L-0.080 and 1.1-tmax/t 2-2.0.

In the thin-walled blade 8c satisfying the relationship of 0.045. ltoreq. tmax/L. ltoreq.0.080, when tmax/t2 is smaller than 1.1, the change in the inter-blade distance from the outer peripheral end portion 8g to the maximum thickness portion TM is small. Thus, if the air flow is once peeled off, reattachment is difficult. On the other hand, when tmax/t2 is larger than 2.0, the variation in the inter-blade distance from the outer peripheral side end portion 8g to the maximum thickness portion TM becomes large. Thereby, since the flow path width between the blades at the maximum thickness portion TM becomes narrow, the friction loss increases. In the thin blade 8c that satisfies the relationship of 0.045 ≦ tmax/L ≦ 0.080, if tmax/t2 satisfies the above-described relationship, the friction loss can be reduced while suppressing the separation, so the efficiency of the cross flow fan 8 can be improved. Therefore, the indoor unit 100 of the air conditioner having excellent energy saving performance can be obtained.

In the indoor unit 100 of an air conditioner according to the present embodiment, in a cross section perpendicular to the rotation axis O, the pressure surface 8j of each of the plurality of blades 8c has a first curved portion (for example, the first curved portion 8Cja, 8Cjb, or 8Cjc) in which the pressure surface 8j side is concave, and a first straight portion (for example, the first straight portion 8Lja, 8Ljb, or 8Ljc) in which one end is connected to the first curved portion and the other end is connected to the inner peripheral end portion 8 h. In a cross section perpendicular to the rotation axis O, the suction surface 8k of each of the plurality of blades 8c has a second curved portion (for example, a second curved portion 8Cka, 8Ckb, or 8Ckc) in which the suction surface 8k side is convex, and a second linear portion (for example, a second linear portion 8Lka, 8Lkb, or 8Lkc) in which one end is connected to the second curved portion and the other end is connected to the inner circumferential end portion 8 h.

According to this configuration, on the suction side of the impeller 8a, the flow that the first curved portion or the second curved portion on the upstream side tries to separate can be caused to adhere again to the first straight portion or the second straight portion on the downstream side. Therefore, abnormal fluid sound due to local peeling can be suppressed. Thus, a high-quality indoor unit of an air conditioner in which fluid abnormal noise is suppressed can be obtained.

In the indoor unit 100 of an air conditioner according to the present embodiment, when the distance between the rotation axis O and the outer peripheral end 8g at the first end 8ca is Rta and the distance between the first end 8ca and the second end 8cb in the direction along the rotation axis O is P,

satisfy the relation of P/(2 × Rta) less than or equal to 0.45 and less than or equal to 0.80.

According to this configuration, since the support plates 8b are arranged at appropriate intervals, even if the second end portions 8cb of the blades 8c on the suction side of the impeller 8a are peeled off, the flow can be suppressed from being unstable by the support plates 8 b. This makes it possible to obtain the cross flow fan 8 that is less likely to stall even if dust accumulates in the filter 5 and has high efficiency at low load.

In the impeller 8a including the thin blades 8c, if the interval between the support plates 8b is too wide, the blades 8 may be deformed when the impeller 8a is assembled, and the efficiency of the cross flow fan 8 may be reduced. In contrast, according to the above configuration, since the air blowing characteristics can be prevented from changing due to the deformation of the vane 8c, a high-quality indoor unit 100 of an air conditioner can be obtained.

In the indoor unit 100 of an air conditioner according to the present embodiment, the pressure surfaces 8j of the plurality of blades 8c have a plurality of arcs having different radii in a cross section perpendicular to the rotation axis O. In a cross section perpendicular to the rotation axis O, the suction surfaces 8k of the plurality of blades 8c have a plurality of arcs having different radii.

Since the suction surface 8k has a plurality of arcs having different radii, even if the flow is separated from a part of the suction surface 8k, the flow can be reattached to another arc having a different radius, and therefore, the loss of the cross flow fan 8 can be reduced. Further, since the pressure surface 8j has a plurality of arcs having different radii, the pressure can be gradually increased on the pressure surface 8j side, and thus the friction loss can be reduced. This can reduce the thickness of the blade 8c while improving the efficiency of the crossflow fan 8, and thus can reduce the weight of the impeller 8 a. Therefore, the indoor unit 100 of the air conditioner is excellent in energy saving performance and light in weight.

Description of reference numerals:

1 … outer shell; 1a … housing body; 1b … front surface panel; 1c … top surface; 2 … suction grill; 2a … opening; 3 … air outlet; 4a … up and down wind vanes; 4b … horizontal wind vanes; 5 … filter; 7 … heat exchanger; 8 … cross-flow fan; 8a … impeller; 8b … support plate; 8c … leaf; an 8ca … first end; 8cb … second end; an 8cc … middle section; 8d … impeller monomer; 8e … fan hub; 8f … end plates; 8fa … fan shaft; 8g … outer peripheral side end portion; 8gm … center; 8h … inner circumference side end; 8hm … center; 8j … pressure side; 8k … negative pressure surface; 8Lj … first straight line; 8Lk … second straight line portion; 9 … stabilizer; 9a … tongue; 9b … upper wall; 9c … drip pan; 10 … guide walls; 11 … room; 11a … wall; 12 … a motor; 12a … motor shaft; 100 … indoor unit; a … rotational displacement angle ratio; e1 … suction side air path; e2 … discharge side air duct; g1, G2 … fan gap; l … blade chord length; lo … blade chord line; mid-point of Lo2 …; lo3 … straight line; o … rotating shaft; p, Rg, Rh, Ri, Rm, Rt … distances; RO … direction of rotation; t1, t2, tmax … wall thickness; TM … maximum wall thickness; TMm … center; distances Δ Le, Δ Leac, Δ Lebc …; the spacing angles of alpha 1 and alpha 2 …; an angle δ …; theta 1 and theta 2 … rotate by a displacement angle.

Claims (9)

1. An indoor unit of an air conditioner includes: a housing having a suction port and a blow-out port; and a cross flow fan housed in the casing,

the cross flow fan includes:

an impeller disposed in an air passage formed in the housing;

a stabilizer that divides the air passage into a suction-side air passage and a discharge-side air passage; and

a guide wall that guides the air blown out from the impeller to the outlet-side air passage to the outlet port,

the impeller has:

a plurality of blades which are respectively arranged on a circumference around a rotation shaft of the impeller and respectively have a first end and a second end as ends along the rotation shaft; and

a support plate that supports the first end portions of the plurality of blades,

the second end portion is disposed forward of the first end portion in a rotation direction of the impeller,

each of the plurality of blades has an inner circumferential end and an outer circumferential end as a radial end around the rotation axis,

a cross-sectional area of the second end portion in a cross-section perpendicular to the rotation axis is smaller than a cross-sectional area of the first end portion in a cross-section perpendicular to the rotation axis,

a distance between the rotation shaft and the outer circumferential side end portion on the second end portion is shorter than a distance between the rotation shaft and the outer circumferential side end portion on the first end portion,

a distance between the rotation shaft and the inner circumference side end portion on the second end portion is longer than a distance between the rotation shaft and the inner circumference side end portion on the first end portion,

a wall thickness of the inner circumferential end portion is larger than a wall thickness of the outer circumferential end portion in a cross section perpendicular to the rotation shaft,

in a cross section perpendicular to the rotation axis, each of the plurality of blades has a maximum thickness portion having a maximum thickness on the inner peripheral end side than a straight line passing through a midpoint of a blade chord line of each of the plurality of blades and perpendicular to the blade chord line,

when a cross section perpendicular to the rotation axis in the first end is defined as a first cross section of each of the plurality of blades, a cross section perpendicular to the rotation axis in the second end is defined as a second cross section of each of the plurality of blades, an inscribed circle in the first cross section in contact with the outer peripheral end, the pressure surface of each of the plurality of blades, and the suction surface of each of the plurality of blades is defined as a first inscribed circle, an inscribed circle in the second cross section in contact with the outer peripheral end, the pressure surface, and the suction surface is defined as a second inscribed circle, an inscribed circle in the first cross section in contact with the inner peripheral end, the pressure surface, and the suction surface is defined as a third inscribed circle, and an inscribed circle in the second cross section in contact with the inner peripheral end, the pressure surface, and the suction surface is defined as a fourth inscribed circle,

the distance between the rotation axis and the center of the first inscribed circle and the distance between the rotation axis and the center of the second inscribed circle are equal,

the distance between the rotating shaft and the center of the third inscribed circle is equal to the distance between the rotating shaft and the center of the fourth inscribed circle.

2. An indoor unit of an air conditioner according to claim 1,

when an inscribed circle in which the maximum thickness portion of the first cross section meets the pressure surface and the negative pressure surface is taken as a fifth inscribed circle and an inscribed circle in which the maximum thickness portion of the second cross section meets the pressure surface and the negative pressure surface is taken as a sixth inscribed circle,

the distance between the rotating shaft and the center of the fifth inscribed circle is equal to the distance between the rotating shaft and the center of the sixth inscribed circle.

3. The indoor unit of an air conditioner according to claim 1 or 2,

when the first cross section and the second cross section are overlapped on the same plane such that the center of the first inscribed circle coincides with the center of the second inscribed circle and the center of the third inscribed circle coincides with the center of the fourth inscribed circle,

the distance between the contour line of the first cross section and the contour line of the second cross section is constant over the entire circumference of each of the plurality of blades.

4. An indoor unit of an air conditioner includes: a housing having a suction port and a blow-out port; and a cross flow fan housed in the casing,

the cross flow fan includes:

an impeller disposed in an air passage formed in the housing;

a stabilizer that divides the air passage into a suction-side air passage and a discharge-side air passage; and

a guide wall that guides the air blown out from the impeller to the outlet-side air passage to the outlet port,

the impeller has:

a plurality of blades which are respectively arranged on a circumference around a rotation shaft of the impeller and respectively have a first end and a second end as ends along the rotation shaft; and

a support plate that supports the first end portions of the plurality of blades,

the second end portion is disposed forward of the first end portion in a rotation direction of the impeller,

each of the plurality of blades has an inner circumferential end and an outer circumferential end as a radial end around the rotation axis,

a cross-sectional area of the second end portion in a cross-section perpendicular to the rotation axis is smaller than a cross-sectional area of the first end portion in a cross-section perpendicular to the rotation axis,

a distance between the rotation shaft and the outer circumferential side end portion on the second end portion is shorter than a distance between the rotation shaft and the outer circumferential side end portion on the first end portion,

a distance between the rotation shaft and the inner circumference side end portion on the second end portion is longer than a distance between the rotation shaft and the inner circumference side end portion on the first end portion,

a wall thickness of the inner circumferential end portion is larger than a wall thickness of the outer circumferential end portion in a cross section perpendicular to the rotation shaft,

in a cross section perpendicular to the rotation axis, each of the plurality of blades has a maximum thickness portion having a maximum thickness on the inner peripheral end side than a straight line passing through a midpoint of a blade chord line of each of the plurality of blades and perpendicular to the blade chord line,

when the distance between the rotating shaft and the outer circumferential end on the first end is Rta, the distance between the rotating shaft and the outer circumferential end on the second end is Rtb, the distance between the rotating shaft and the inner circumferential end on the first end is Ria, the distance between the rotating shaft and the inner circumferential end on the second end is Rib, and the distance between the first end and the second end in the direction along the rotating shaft is P,

satisfies the relationship of (Rta-Rtb)/P ═ Rib-Ria)/P.

5. An indoor unit of an air conditioner includes: a housing having a suction port and a blow-out port; and a cross flow fan housed in the casing,

the cross flow fan includes:

an impeller disposed in an air passage formed in the housing;

a stabilizer that divides the air passage into a suction-side air passage and a discharge-side air passage; and

a guide wall that guides the air blown out from the impeller to the outlet-side air passage to the outlet port,

the impeller has:

a plurality of blades which are respectively arranged on a circumference around a rotation shaft of the impeller and respectively have a first end and a second end as ends along the rotation shaft; and

a support plate that supports the first end portions of the plurality of blades,

the second end portion is disposed forward of the first end portion in a rotation direction of the impeller,

each of the plurality of blades has an inner circumferential end and an outer circumferential end as a radial end around the rotation axis,

a cross-sectional area of the second end portion in a cross-section perpendicular to the rotation axis is smaller than a cross-sectional area of the first end portion in a cross-section perpendicular to the rotation axis,

a distance between the rotation shaft and the outer circumferential side end portion on the second end portion is shorter than a distance between the rotation shaft and the outer circumferential side end portion on the first end portion,

a distance between the rotation shaft and the inner circumference side end portion on the second end portion is longer than a distance between the rotation shaft and the inner circumference side end portion on the first end portion,

a wall thickness of the inner circumferential end portion is larger than a wall thickness of the outer circumferential end portion in a cross section perpendicular to the rotation shaft,

in a cross section perpendicular to the rotation axis, each of the plurality of blades has a maximum thickness portion having a maximum thickness on the inner peripheral end side than a straight line passing through a midpoint of a blade chord line of each of the plurality of blades and perpendicular to the blade chord line,

in a cross section perpendicular to the rotation axis, when a blade chord length of each of the plurality of blades is L, a wall thickness of the outer circumferential end portion is t2, and a wall thickness of the maximum wall thickness portion is tmax,

satisfies the relation of 0.045-tmax/L-0.080 and 1.1-tmax/t 2-2.0.

6. An indoor unit of an air conditioner includes: a housing having a suction port and a blow-out port; and a cross flow fan housed in the casing,

the cross flow fan includes:

an impeller disposed in an air passage formed in the housing;

a stabilizer that divides the air passage into a suction-side air passage and a discharge-side air passage; and

a guide wall that guides the air blown out from the impeller to the outlet-side air passage to the outlet port,

the impeller has:

a plurality of blades which are respectively arranged on a circumference around a rotation shaft of the impeller and respectively have a first end and a second end as ends along the rotation shaft; and

a support plate that supports the first end portions of the plurality of blades,

the second end portion is disposed forward of the first end portion in a rotation direction of the impeller,

each of the plurality of blades has an inner circumferential end and an outer circumferential end as a radial end around the rotation axis,

a cross-sectional area of the second end portion in a cross-section perpendicular to the rotation axis is smaller than a cross-sectional area of the first end portion in a cross-section perpendicular to the rotation axis,

a distance between the rotation shaft and the outer circumferential side end portion on the second end portion is shorter than a distance between the rotation shaft and the outer circumferential side end portion on the first end portion,

a distance between the rotation shaft and the inner circumference side end portion on the second end portion is longer than a distance between the rotation shaft and the inner circumference side end portion on the first end portion,

a wall thickness of the inner circumferential end portion is larger than a wall thickness of the outer circumferential end portion in a cross section perpendicular to the rotation shaft,

in a cross section perpendicular to the rotation axis, each of the plurality of blades has a maximum thickness portion having a maximum thickness on the inner peripheral end side than a straight line passing through a midpoint of a blade chord line of each of the plurality of blades and perpendicular to the blade chord line,

when a distance between the rotation axis and the outer circumferential side end portion on the first end portion is Rta and a distance between the first end portion and the second end portion in a direction along the rotation axis is P,

satisfy the relation of P/(2 × Rta) less than or equal to 0.45 and less than or equal to 0.80.

7. An indoor unit of an air conditioner according to any one of claims 1, 2, and 4 to 6, wherein,

when a rotational displacement angle of the second end portion with respect to the first end portion with the rotation axis as a center is set to θ 2[ deg ], and a distance between the first end portion and the second end portion in a direction along the rotation axis is set to P [ mm ],

satisfies the relation of theta 2/P being more than or equal to 0.02[ deg/mm ] and less than or equal to 0.05[ deg/mm ].

8. An indoor unit of an air conditioner according to any one of claims 1, 2, and 4 to 6, wherein,

in a cross section perpendicular to the rotation axis, each of the pressure surfaces of the plurality of blades has a first curved portion whose pressure surface side is concave and a first straight portion whose one end is connected to the first curved portion and whose other end is connected to the inner circumferential end portion,

in a cross section perpendicular to the rotation axis, the suction surface of each of the plurality of blades has a second curved portion whose suction surface side is convex, and a second linear portion whose one end is connected to the second curved portion and whose other end is connected to the inner circumferential end.

9. An indoor unit of an air conditioner according to any one of claims 1, 2, and 4 to 6, wherein,

a pressure surface of each of the plurality of blades has a plurality of circular arcs having different radii in a cross section perpendicular to the rotation axis,

in a cross section perpendicular to the rotation axis, the negative pressure surface of each of the plurality of blades has a plurality of circular arcs having different radii.

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