Patent Grant
9759441
This application is a U.S. national stage application of PCT/JP2012/002178 filed on Mar. 29, 2012 and is based on Japanese Patent Application No. 2011-130031 filed on Jun. 10, 2011, the contents of which are incorporated herein by reference.
The present invention relates to an air-conditioning apparatus and in particular relates to an indoor unit of a separate-type air-conditioning apparatus equipped with the indoor unit and an outdoor unit.
An indoor unit of an air-conditioning apparatus is installed in a room (in a room of a house or office) subjected to air conditioning. Indoor air sucked through the air inlet exchanges heat in a heat exchanger with a refrigerant circulated in a refrigeration cycle so as to heat the indoor air during heating operation and cool the indoor air during cooling operation. The indoor air heated or cooled is blown into the room through the air outlet. For this purpose, a fan and a heat exchanger are housed in an indoor unit main body.
Among many types of the existing indoor units of the air-conditioning apparatuses, it is well-known that some types of the indoor units such as a wall-installation type, which have an elongated air outlet, and a ceiling concealing type, which blows air in a single direction, use cross flow fans (also referred to as tangential fans or transverse fans) as their air sending device. With respect to an airflow flowing from an air inlet to an air outlet in the indoor unit of the air-conditioning apparatus, a heat exchanger is disposed upstream of the cross flow fan, that is, the heat exchanger is disposed between the air inlet and the cross flow fan, and the air outlet is positioned downstream of the cross flow fan. The length of the air outlet of the indoor unit in the longitudinal direction is substantially the same as the entire length of the cross flow fan in the longitudinal direction (rotational axis direction). Components such as drive motor and support portions that support the rotating shaft of the cross flow fan are disposed further to the outside in the longitudinal direction of the both ends of the cross flow fan with a space between these components and each end of the cross flow fan.
The cross flow fan (simply referred to as “fan” hereafter) includes a plurality of individual impeller units connected to one another in the rotational axis direction. In each of the individual impeller units, a plurality of blades, each of which is curved so as to have an arc shape in section, are secured to an annular (ring-shaped) support plate, which is a flat plate having outer and inner diameters. The blades are inclined by a predetermined angle relative to the support plate and secured to the support plate so as to form concentric annular shapes. A discoid end plate is secured to ends of the blades of the individual impeller unit at one end in the rotational axis direction. The rotating shaft supported by a bearing portion of the indoor unit main body is attached to the end plate. The individual impeller unit at the other end in the rotational axis direction includes an end plate with a boss. Unlike the support plates in other portions, the end plate with a boss has a boss portion at its center. The motor rotating shaft of the drive motor is secured to the boss. When the drive motor rotary drives, the fan is rotated about the rotational axis, which is the center of the rotating shaft. The blades are inclined so that their respective outer circumferential blade ends are positioned at the front in the rotational direction.
Hereafter, each of the individual impeller units arranged in series in the rotational axis direction is referred to as a “unit” of the fan for the convenience of description. The individual impeller unit located at each end of the fan in the rotational axis direction is referred to as an “end unit.”
As the fan is rotated, indoor air is sucked into the indoor unit main body of the air-conditioning apparatus through the air inlet. The sucked air becomes conditioned air, the temperature of which has been adjusted as described above while passing through the heat exchanger. The conditioned air crosses the fan, and after that, passes through an air path that extends to the air outlet and is blown into the room through the air outlet formed in a lower portion of the indoor unit main body.
The pressure inside the indoor unit is lower than the atmospheric pressure because of frictional resistance (pressure loss) applied to air while the air is passing through the heat exchanger. The fan provides energy to the airflow so that the airflow surpasses the atmospheric pressure, thereby blowing the air from the air outlet. However, when the energy provided to the airflow from the fan is not sufficient to surpass the atmospheric pressure, the pressure inside the indoor unit becomes lower than the atmospheric pressure outside the indoor unit. In this case, indoor air is sucked into the indoor unit through the air outlet. This phenomenon is referred to as “reverse suction.”
Reverse suction tends to occur near the both ends of the fan in the rotational axis direction. The reason of this is as follows.
At each end of the fan in the rotational axis direction, an end plate, which is part of the individual impeller unit as a rotating body, and a side wall of the indoor unit main body are disposed. The side wall defines a side surface of an air path and is disposed further to the outside than the end plate so as to oppose the side plate. The end plate and the side plate are spaced apart from each other by about 5 mm so as to prevent the occurrence of rotational friction, which may otherwise occur due to contact of the end and side plates with each other. A space formed between the end plate and the side wall opposite the end plate is positioned at the outside of each end of the fan in the rotational axis direction. This space is in an atmosphere in which the pressure is lower than the atmospheric pressure due to the pressure loss while the air is passing through the heat exchanger. Thus, it is considered that reverse suction tends to occur due to the pressure difference between the pressure in the space and the atmospheric pressure outside the indoor unit. When reverse suction occurs, the air volume of the entire fan is reduced, thereby degrading the performance of the fan. Furthermore, turbulence of the airflow is caused by reverse suction, thereby increasing noise. When reverse suction occurs during cooling operation, droplets of condensed water may scatter in the room (this scattering is referred to as “scattering of water droplets”). The scattering of water droplets is a phenomenon in which high-humidity indoor air having flowed into the indoor unit due to reverse suction is condensed through its contact with low-temperature wall surfaces inside the indoor unit, and the condensed water then becomes water droplets and may be scattered into the room. In particular, when draft resistance is increased by, for example, dust accumulated in the air inlet, sufficient energy is unlikely to be provided by the fan, and accordingly, occurrence of reverse suction is facilitated.
There is an example of a structure in order to prevent above-described reverse suction. In this structure, a member having an outer circumstantial surface is attached to each end of the cross flow fan in the rotational axis direction. The size of the member is increasing toward each side surface so as to form a bell shape. With the bell-shaped member, the gap between each end of the fan in the rotational axis direction and a space, in which the pressure is lower than the atmospheric pressure, formed outside the end of the fan is reduced so as to prevent the reverse suction (for example, see Patent Literature 1).
Patent Literature 1: Japanese Unexamined Patent Application Publication No. 6-33893 (paragraphs 0009 to 0013 and FIGS. 1 and 3)
The member having the outer circumferential surface, the size of which is increasing toward the side wall so as to form a bell shape, provided at each end of the fan in the rotational axis direction (longitudinal direction) is intended to block air that attempts to flow into the space between the end of the fan and the side wall. The air that attempts to reversely flow into the indoor unit through each end of the air outlet is caused to flow back toward the air outlet by the bell-shaped outer circumferential surface, thereby reverse suction is prevented. However, in order to eliminate generation of the rotational friction between the ends of the fan and the side walls, the gaps between the rotating fan and the fixed side walls of the indoor unit main body of the air-conditioning apparatus cannot be completely eliminated. Thus, it is difficult to prevent reverse suction, which is generated by air passing through the gap between each of the members having the bell-shaped expanded outer circumferential surface and a corresponding one of the side walls.
The present invention is proposed in order to solve the above-described problem. An object of the present invention is to obtain an air-conditioning apparatus, in which reverse suction can be prevented, a large air volume can be maintained, and power consumption and noise can be reduced.
An air-conditioning apparatus according to the present invention includes an indoor unit main body that has an air inlet, through which indoor air is sucked, and an air outlet elongated in a left-right direction, from which air is blown.
The air-conditioning apparatus also includes a cross flow fan provided in the indoor unit main body. A length of the cross flow fan in a rotational axis direction is longer than a length of the air outlet in a longitudinal direction such that the cross flow fan extends beyond both ends of the air outlet in the longitudinal direction and the rotational axis direction of the cross flow fan matches the left-right direction of the indoor unit main body.
The air-conditioning apparatus also includes deflectors provided in the indoor unit main body. The deflectors oppose airflows blown from fan extensions, which are portions of the cross flow fan and positioned beyond the both ends of the air outlet in the longitudinal direction.
In the air-conditioning apparatus, the cross flow fan includes an individual impeller unit that has a plurality of blades provided in a circumferential direction of annular support plates.
In the air-conditioning apparatus, first blades opposing the air outlet and second blades in the extensions opposing the deflectors are disposed between the support plates neighboring each other, the second blades being differently shaped from the first blades, and an airflow blown through the second blades in the extensions flows at a lower wind speed than an airflow blown through the first blades opposing the air outlet.
According to the present invention, the stagnation pressure higher than the atmospheric pressure can be generated near each end of the air outlet by causing the outlet airflow from the fan extension of the cross flow fan to impinge upon a corresponding one of the deflectors. Thus, reverse suction, in which the indoor air flows from the outside of the indoor unit into the indoor unit through the air outlet, can be prevented. Accordingly, degradation of the performance of the fan, an increase in noise, scattering of water droplets, and the like, which are caused by generation of reverse suction, can be prevented. Furthermore, the wind speed of the airflows blown from portions, which oppose the respective deflectors in the rotational axis direction of the fan, is set to be lower than the wind speed of the airflow blown from a portion opposing the air outlet. Thus, reverse suction is prevented while a large air volume of the entire fan is maintained, and accordingly, power consumption and noise can be reduced.
Embodiment 1
Embodiment 1 of the present invention will be described below with reference to the drawings.
As illustrated in
The rear surface of the outlet air path 11 opposite the fan extension 8a provided at each end of the fan 8 in the rotational axis direction AX is defined by the upstream side of the rear guide 10 up to an intermediate position thereof, and, as illustrated in
In a portion of the cross flow fan 8 except for the fan extensions 8a in the rotational axis direction AX, that is, a central portion of the fan 8 in the rotational axis direction AX, the rear surface of the outlet air path 11 is, as illustrated in
Examples of the lengths of the fans used in Embodiment 1 are as follows.
That is, the outer diameter K2 and the inner diameter K1 of the annular support plate 12 secured to the blades 13 at the end portion of each individual impeller unit 14 are respectively φ110 mm and φ60 mm, and a plurality of, for example, 35 blades 13 are secured at the circumference of each support plate 12. In the rotational axis direction AX, for example, a length L1 of the air outlet 3 in the longitudinal direction is, 610 mm, an entire length L2 of the cross flow fan 8 in the rotational axis direction AX is 640 mm, and a specified width L3 of each deflector 18 in the rotational axis direction AX is 30 mm. Each deflector 18 is superposed with a corresponding one of the fan extensions 8a by, for example, about a half the length L3 thereof in the rotational axis direction AX, and a length Z of the fan extension 8a in the rotational axis direction AX is, for example, about 15 mm. Spaces formed between the end plates 12a and 12b at the both ends of the fan 8 and the respective side walls 30 are denoted by S. The length of the space S in the rotational axis direction AX is, for example, 15 mm. The length of each end unit 14a in the rotational axis direction AX is from 25 to 70 mm, and the length of each of the units 14 other than two end units 14a in the rotational axis direction AX is about 80 mm.
As illustrated in
The difference in blade sectional shape between the blade 13a, which opposes the fan extension 8a, that is, the deflector 18, and the blade 13b, which opposes the air outlet 3, is described. Here, the blades 13a, which opposes the deflector 18 in the rotational axis direction AX, is referred to as a deflector opposing blade portion 13a, and the blade 13b, which opposes the air outlet 3 (in other words, the blade in a portion not opposing the deflector 18) is referred to as an air outlet opposing blade portion 13b.
A straight line that connects the inner circumferential blade end portion Ha and the outer circumferential blade end portion Ga to each other is referred to as a chord line Ma, and a straight line that connects the inner circumferential blade end portion Hb and the outer circumferential blade end portion Gb to each other is referred to as a chord line Mb. Here, the length of the chord line Ma of the deflector opposing blade portion 13a is set to be shorter than the length of the chord line Mb of the air outlet opposing blade portion 13b in Embodiment 1. For example, the length of the chord line Ma is set to 13 to 14 mm, the length of the chord line Mb is set to 15 to 16 mm, and the length of the chord line Ma is set to shorter than that of the chord line Mb by 2 to 3 mm. Here, the locus of rotation of the outer circumferential blade end portion Ga, Gb is defined as a blade outer diameter and represented as a blade outer diameter 24. The loci of rotation of the inner circumferential blade end portions Ha and Hb are defined as blade inner diameters and represented as blade inner diameters 25. In Embodiment 1, the outer circumferential blade end portion Ga of the deflector opposing blade portion 13a and the outer circumferential blade end portion Gb of the air outlet opposing blade portion 13b are, as illustrated in
Operation of the blade according to Embodiment 1 is described below with reference to
The rotation speeds for operation of the cross flow fan 8 disposed in the indoor unit 1 of the air-conditioning apparatus are set in accordance with operational modes such as, weak cooling and strong cooling. The distance Y between the deflector 18 and the outer circumference of the cross flow fan 8, the length Z of the deflector opposing blade portion 13a in the rotational axis direction AX, and the length of the chord line Ma of the deflector opposing blade portion 13a are determined so that the stagnation pressure P1 can be higher than the atmospheric pressure P0 at the wind speed in operation at the lowest rotation speed. When the deflector opposing blade portion 13a and the deflector 18 are provided as described above, during operation of the indoor unit 1, that is, during rotation of the cross flow fan 8, the pressure in the impinging region E3 for the end unit 14a of the cross flow fan 8 can be the stagnation pressure P1 (>atmospheric pressure P0). By setting the pressure in the impinging region E3 that communicates with the space S such that the stagnation pressure P1>the atmospheric pressure P0, a pressure difference is generated. Thus, entrance of the indoor air of the atmospheric pressure P0 is prevented by the stagnation pressure P1. Accordingly, reverse suction, in which the indoor air flows from the outside of the indoor unit 1 through the air outlet 3 into the space S, where the pressure is low, inside the indoor unit 1 can be prevented from occurring.
However, with the deflector 18, by causing the outlet airflow to impinge upon the deflector 18, draft resistance is increased. This increases load for the cross flow fan 8, and accordingly, leads to an increase in energy loss and an increase in noise. In contrast, in Embodiment 1, regarding the blade shape of the end unit 14a of the cross flow fan 8, each end unit 14a has the blade portions 13a and 13b, the shapes of which are different from each other, and the lengths of the chord lines Ma and Mb are set to be different from each other as illustrated in
When the blades used in the entire length of the cross flow fan 8 in the rotational axis direction AX or in the entire length of the end unit 14a are the blades having the short chord line Ma, energy provided to the airflow is not sufficient, and accordingly, a sufficient air volume cannot be obtained from the entirety of the fan. When the blades used in the entire length of the end unit 14a are the blades having the long chord line Mb, the impact loss of the airflow that impinges upon the deflectors 18 in the fan extensions 8a is increased, thereby increasing the load for the fan. This causes an increase in energy loss and an increase in noise. Regarding the blade shapes according to Embodiment 1, the blade portion 13a opposite the deflector 18 has the blade shape in which the chord line is the short chord line Ma so as to provide a minimum energy, at which the stagnation pressure P1 is slightly higher than the atmospheric pressure P0, to the airflow. The blade portion 13b not opposing the deflector 18 has the blade shape in which the chord line is the chord line Mb that is longer than the chord line Ma so as to provide much energy to the airflow.
Since the wind speed (air volume) of the airflow Aa obtained by the deflector opposing blade portion 13a is lower than that of the airflow Ab, the stagnation pressure P1 higher than the atmospheric pressure P0 is obtained and, at the same time, the energy loss due to the airflow impinging upon the deflector 18 is reduced as much as possible. Furthermore, since the wind speed Va in the impinging region E3 is lower than the wind speed Vb at which the air is directed toward the air outlet 3, in comparison with the case in which the airflow at the wind speed Vb impinges upon the deflector 18, an impact sound is reduced, thereby a low-noise fan is realized. In addition, by setting the wind speed Vb of the airflow Ab obtained by the air outlet opposing blade portion 13b to be higher than that of the airflow Aa, a large air volume of the entirety of the fan is maintained. The length of the cross flow fan 8 in the rotational axis direction AX is longer than the length of the air outlet 3 in the longitudinal direction, thereby allowing the speed Vb of the airflow Ab blown from the air outlet 3 over a range from the one end to the other end of the air outlet 3 in the longitudinal direction to be increased. Thus, the occurrence of reverse suction can be further prevented. Even when the stagnation pressure P1 is, for example, only slightly higher than the atmospheric pressure P0, reverse suction that tends to occur at the both end portions of the air outlet 3 can be reliably prevented because of the high speed Vb of the airflow Ab blown from the air outlet 3 over a range from the one end to the other end of the air outlet 3 in the longitudinal direction. By preventing this reverse suction, a scattering of water droplets can be prevented. The scattering of water droplets is a phenomenon in which high-humidity indoor air having flowed into the indoor unit 1 due to reverse suction during cooling operation is condensed through its contact with low-temperature wall surfaces inside the indoor unit 1, and the condensed water then becomes water droplets and scattered into the room. Furthermore, by maintaining a large air volume of the entire fan, the performance of the fan is improved and power consumption can be reduced.
As described above, the air-conditioning apparatus according to Embodiment 1 includes the following components: the air inlet grille 2 that is provided in the upper portion 1a of the indoor unit 1 main body of the air-conditioning apparatus, and indoor air is sucked therethrough; the air outlet 3 that is formed in the lower portion of the indoor unit 1 main body of the air-conditioning apparatus so as to be elongated in the left-right direction of the indoor unit 1 main body of the air-conditioning apparatus, and the Indoor air having undergone heat exchange in the heat exchanger 7 is blown into the room therethrough; the cross flow fan 8 that is provided in the indoor unit 1 main body, the length of which in the rotational axis direction AX is longer than the length of the air outlet 3 in the longitudinal direction such that the cross flow fan 8 extends beyond the both ends of the air outlet 3 in the longitudinal direction and the rotational axis direction of the cross flow fan 8 matches the left-right direction of the indoor unit 1 main body; and the deflectors 18 that are provided in the indoor unit 1 main body and oppose the outlet airflows blown from the fan extensions 8a, which are portions of the cross flow fan 8 positioned beyond the both ends of the air outlet 3 in the longitudinal direction. The cross flow fan 8 includes individual impeller units 14 having the plurality of blades 13 provided in the circumferential direction of the annular support plate 12. The blade shape of the deflector opposing blade portion 13a of the extension 8a is different from that of the air outlet opposing blade portion 13b opposing the air outlet 3. The blade shape of the deflector opposing blade portion 13a is formed so as to obtain the outlet airflow Aa, the wind speed Va of which is lower than that of the outlet airflow Ab blown from the air outlet opposing blade portion 13b opposing the air outlet 3. The cross flow fan 8 is operated so that the stagnation pressure between the deflector 18 and the extension 8a is higher than the atmospheric pressure. Thus, the stagnation pressure P1 higher than the atmospheric pressure P0 is generated in front of the deflector 18 by the outlet airflow Aa. This can prevent reverse suction in which the indoor air flows from the outside of the indoor unit 1 into the indoor unit 1 through the air outlet 3. By preventing this reverse suction, turbulence of the airflow can be reduced, and accordingly, scattering of water droplets during cooling operation of the air-conditioning apparatus can be prevented. Also, a large air volume of the airflow Ab blown from the air outlet 3 can be reliably obtained, and accordingly, the performance of the fan can be improved. Furthermore, the wind speed Va of the outlet airflow Aa directed toward the deflector 18 can be smaller than the wind speed of the outlet airflow Ab directed toward the air outlet 3. Thus, an air-conditioning apparatus can be obtained, with which the energy loss and noise caused when the airflow impinges upon the deflector 18 can be suppressed.
In particular, when a line segment that connects the outer circumferential blade end portion G and the inner circumferential blade end portion H to each other in a section perpendicular to the rotational axis 17 of the blade 13 is defined as the chord line M, the length of the chord line Ma of the blade 13a of the fan extension 8a is set to be shorter than the length of the chord line Mb of the blade 13b opposing the air outlet 3. Thus, energy provided to the airflow changes in accordance with the length of the chord line M, and the wind speed Va of the outlet airflow Aa blown from the deflector opposing blade portion 13a, which is the blade of the fan extension 8a, is lower than the wind speed Vb of the outlet airflow Ab blown from the air outlet opposing blade portion 13b opposing the air outlet 3. Accordingly, the energy loss can be suppressed and reverse suction can be prevented, and noise due to an airflow generated at the deflector 18 can be reduced. In addition, the outlet airflow Ab, which flows at the speed Vb higher than the speed Va of the outlet airflow Aa blown from the blade portion 13a opposite the deflector 18, is blown from the blade portion 13b opposing the air outlet 3 so as to allow a large air volume to be reliably obtained from the entire fan.
Although the chord line Mb of the air outlet opposing blade portion 13b is longer than the chord line Ma of the deflector opposing blade portion 13a and the difference in length between the chord lines is 2 to 3 mm herein, the lengths of the chord lines are not limited to these. It is sufficient that the chord line Mb of the air outlet opposing blade portion 13b be longer than the length of the chord line Ma of the deflector opposing blade portion 13a by one eighth to one third of the length of the chord line Ma of the deflector opposing blade portion 13a. For example, when the chord line Ma is set to 12 mm, the chord line Mb is set to 13.5 to 16 mm. When the chord line Mb is shorter than 13.5 mm, the effect of increasing the air volume cannot be obtained, and when the chord line Mb is longer than 16 mm, the size of the step DG in the boundary region increases in each of the end units 14a, and accordingly, air cannot smoothly flow.
In order to obtain the chord lines M having different lengths, the outer circumferential blade end portions Ga and Gb are set at the same position and the inner circumferential blade end portions Ha and Hb are set at different positions in a single blade. However, the positional settings are not limited to these. Alternatively, the outer circumferential blade end portions Ga and Gb may be set at positions different from each other. The inner circumferential blade end portions Ha and Hb may be set at positions different from each other and the outer circumferential blade end portions Ga and Gb may be set at positions different from each other.
Preferably, the boundary portion D illustrated in
In the two types of significantly different sectional shapes (13a and 13b) on one and the other side of the boundary portion D as illustrated in
The transition portion 13c does not necessarily have a shape so as to connect the deflector opposing blade portion 13a and the air outlet opposing blade portion 13b to each other by a straight line. The transition portion 13c may have another shape. For example, the deflector opposing blade portion 13a and the air outlet opposing blade portion 13b may be connected by an arc shaped curve. In this case, the arc shape may be convex toward the air outlet 3 side or concave toward the air outlet 3 side.
As described above, in Embodiment 1, in the boundary portion D where the blade shape is changed in the rotational axis direction AX of the cross flow fan 8, the blade shapes of the deflector opposing blade portion 13a and the air outlet opposing blade portion 13b are connected to each other by an inclined straight line or a convex or concave curved shape so that the blade shapes are smoothly changed. With this structure, generation of a vortex in a portion where the blade shapes is changed is prevented, and accordingly, the energy loss can be reduced.
Embodiment 2
Here, the outlet angle α is described. It is defined that, in a section of the blade 13 perpendicular to the rotational axis 17, the locus of rotation of the outer circumferential blade end portion Ga, Gb is the blade outer diameter 24, the camber line 21 is a line that extends in the center between the positive pressure surface 19, which is at the front in the rotational direction of the blade 13, and the negative pressure surface 20, which is at the rear in the rotational direction, and the outlet angle α is an angle formed between a tangent of the blade outer diameter 24 and the tangent of the camber line 21 at an intersection of the blade outer diameter 24 and the camber line 21. Thus, an outlet angle αa of the deflector opposing blade portion 13a is an angle formed between a tangent F1a (indicated by the solid line) of the blade outer diameter 24 and the tangent F2a (indicated by the solid line) of the camber line 21a at the outer circumferential blade end portion Ga, which is an intersection of the blade outer diameter 24 and the camber line 21a. An outlet angle αb of the air outlet opposing blade portion 13b is an angle formed between a tangent F1b (indicated by the dotted line) of the blade outer diameter 24 and the tangent F2b (indicated by the dotted line) of the camber line 21b at the outer circumferential blade end portion Gb, which is an intersection of the blade outer diameter 24 and the camber line 21b.
In Embodiment 2, the outlet angle αa of the deflector opposing blade portion 13a is smaller than the outlet angle αb of the air outlet opposing blade portion 13b. For example, the outlet angle αa of the deflector opposing blade portion 13a is set to 24 to 26 degrees, and the outlet angle αb of the air outlet opposing blade portion 13b is set to 26 to 28 degrees. Here, the inner circumferential blade end portion Ha of the deflector opposing blade portion 13a and the inner circumferential blade end portion Hb of the air outlet opposing blade portion 13b are set at the same position.
As described above, blowing directions of the outlet airflows Ab and Aa blown between the blades vary in accordance with the outlet angle α.
In particular, when determining the outlet angle αa of the deflector opposing blade portion 13a, it is desirable that the deflector opposing blade portion 13a has a shape so as to provide a minimum energy to the airflow, the minimum energy being energy with which the stagnation pressure P1 is slightly higher than the atmospheric pressure P0 in an operational mode in which the fan is rotated at the lowest rotation speed. By obtaining the stagnation pressure P1 higher than the atmospheric pressure P0, reverse suction, in which air flows from the outside of the indoor unit 1 into the indoor unit 1, can be prevented. Furthermore, since the minimum stagnation pressure P1 required to prevent reverse suction is obtained, the energy loss due to the impinging flow can be reduced and an increase in noise can be suppressed.
In the air outlet opposing blade portion 13b opposing the air outlet 3, the outlet angle αb is larger than the outlet angle αa of the deflector opposing blade portion 13a. Thus, as indicated by the dotted arrows in
As described above, according to Embodiment 2, it is defined that, in a section of the blade 13 perpendicular to the rotational axis 17, the blade outer diameter 24 is the locus of rotation of the outer circumferential blade end portion G, the camber line 21 is a line that extends in the center between the positive pressure surface 19, which is at the front in the rotational direction of the blade 13, and the negative pressure surface 20, which is at the rear in the rotational direction, and the outlet angle α is an angle formed between the tangent F1 of the blade outer diameter 24 and the tangent F2 of the camber line 21 at an intersection of the blade outer diameter 24 and the camber line 21. Here, by setting the outlet angle αa of the blade 13a of the fan extension 8a to be smaller than the outlet angle αb of the blade 13b opposing the air outlet 3, the proportions of the fan radial direction component and the rotational direction component of the outlet airflow change in accordance with the outlet angle α. With the blade 13a of the extension 8a, the outlet airflow Aa can be obtained. The outlet airflow Aa flows at the wind speed Va lower than the wind speed Vb of the outlet airflow Ab blown from the blade 13b opposing the air outlet 3. This outlet airflow Aa causes the stagnation pressure P1 higher than the atmospheric pressure P0 to be generated in front of the deflector 18. This can prevent reverse suction in which the indoor air flows from the outside of the indoor unit 1 into the indoor unit 1 through the air outlet 3. Also, a large air volume of the airflow Ab blown from the air outlet 3 can be reliably obtained, and accordingly, the performance of the fan can be improved. Furthermore, in comparison with the wind speed Vb of the outlet airflow Ab blown toward the air outlet 3, the wind speed Va of the outlet airflow Aa blown toward the deflector 18 can be reduced. Thus, an air-conditioning apparatus can be obtained, with which the energy loss and noise caused when the airflow impinges upon the deflector 18 can be suppressed.
Here, in order to obtain the outlet angles α different from each other, the inner circumferential blade end portions Ha and Hb are set at the same position and the outer circumferential blade end portions Ga and Gb are set at different positions in a single blade. However, the positional settings are not limited to these. Alternatively, the inner circumferential blade end portions Ha and Hb may be set at positions different from each other. The outer circumferential blade end portions Ga and Gb may be set at positions different from each other and the inner circumferential blade end portions Ha and Hb may be set at positions different from each other.
Embodiment 3
Here, the camber angle βa of the deflector opposing blade portion 13a and the camber angle βb of the air outlet opposing blade portion 13b are different from each other and satisfy the following relationship: camber angle βa<camber angle βb. For example, the camber angle βa of the deflector opposing blade portion 13a is set to about 40 degrees, and the camber angle βb of the air outlet opposing blade portion 13b is set to about 45 degrees.
Here, in the case where the shapes of the deflector opposing blade portion 13a and the air outlet opposing blade portion 13b are differently formed so that the camber angle βa is smaller than the camber angle βb while the camber line 22a of the deflector opposing blade portion 13a coincides with the camber line 22b of the air outlet opposing blade portion 13b, this structure is equal to the following structure in which the curved shapes of the positive pressure surfaces 19 coincide with each other but the blade shapes have the chord lines of different lengths as described in Embodiment 1. As a result, the area of the positive pressure surface 19 increases as the camber angle β increases. Thus, regarding the wind speed of the outlet airflow, the wind speed Va of the outlet airflow Aa blown from the deflector opposing blade portion 13a having a small camber angle βa is lower than the outlet airflow Ab blown from the air outlet opposing blade portion 13b having a large camber angle βb.
In particular, when determining the camber angle βa of the deflector opposing blade portion 13a, it is desirable that the deflector opposing blade portion 13a has a shape so as to provide a minimum energy to the airflow, the minimum energy being energy with which the stagnation pressure P1 is slightly higher than the atmospheric pressure P0 in an operational mode in which the cross flow fan 8 is rotated at the lowest rotation speed. By obtaining the stagnation pressure P1 higher than the atmospheric pressure P0, reverse suction, in which air flows from the outside of the indoor unit 1 into the indoor unit 1, can be prevented. Furthermore, since the minimum stagnation pressure P1 required to prevent reverse suction is obtained, the energy loss due to the impinging airflow can be suppressed. Also, since the speed of the wind that impinges upon the deflector 18 is reduced, noise can be reduced.
Since the camber angle βb of the air outlet opposing blade portion 13b not opposing the deflector 18 is set to be larger than the camber angle βa of the deflector opposing blade portion 13a, the shape of the air outlet opposing blade portion 13b is more significantly curved than that of the positive pressure surface 19 of the deflector opposing blade portion 13a. This increases energy provided to the airflow by the blade portion 13b. Thus, the outlet airflow Ab passing between the blades 13b and provided with much energy is introduced into the air outlet 3 at the wind speed Vb higher than the wind speed Va. Since the sufficient wind speed Vb (air volume) can be obtained by the air outlet opposing blade portion 13b opposing the air outlet 3, a large air volume can be obtained from the entire cross flow fan 8. Thus, the performance of the fan can be improved and power consumption can be reduced. Since the outlet airflow Ab flowing at the sufficient wind speed of Vb (air volume) blown from the air outlet 3 over a range from the one end to the other end of the air outlet 3 in the longitudinal direction can be obtained, reverse suction, in which air attempts to flow from the outside of the indoor unit 1 into the indoor unit 1 through the air outlet 3, can be prevented.
As described above, according to Embodiment 3, it is defined that, in the section of the blade 13 perpendicular to the rotational axis 17, the camber line 22 is a line that extends in the center between the positive pressure surface 19, which is at the front in the rotational direction of the blade 13, and the negative pressure surface 20, which is at the rear in the rotational direction, and the central angle of the sector N, the arc of which is the camber line 22, is a camber angle β. Here, the camber angle βa of the deflector opposing blade portion 13a of the extension 8a is set to be smaller than the camber angle βb of the air outlet opposing blade portion 13b opposing the air outlet 3. Thus, energy provided to the airflow changes in accordance with the size of the camber angle β, and the outlet airflow Aa, the wind speed of which is lower than the wind speed Vb of the outlet airflow Ab blown from the air outlet opposing blade portion 13b opposing the air outlet 3, blown from the deflector opposing blade portion 13a of the fan extension 8a can be obtained. By causing the outlet airflow Aa to impinge upon the deflector 18, the stagnation pressure P1 higher than the atmospheric pressure P0 is generated in front of the deflector 18. This can prevent reverse suction in which the indoor air flows from the outside of the indoor unit 1 into the indoor unit 1 through the air outlet 3. By preventing this reverse suction, turbulence of the airflow can be reduced, and accordingly, scattering of water droplets during cooling operation of the air-conditioning apparatus can be prevented. Also, a large air volume of the airflow Ab blown from the air outlet 3 can be reliably obtained, and accordingly, the performance of the fan can be improved. Furthermore, the wind speed Va of the outlet airflow Aa directed toward the deflector 18 can be smaller than the wind speed of the outlet airflow Ab directed toward the air outlet 3. Thus, an air-conditioning apparatus can be obtained, with which the energy loss and noise caused when the airflow impinges upon the deflector 18 can be suppressed.
Here, in order to obtain the camber angles βa and βb of the deflector opposing blade portion 13a and the air outlet opposing blade portion 13b such that the camber angles βa and βb are different from each other, the outer circumferential blade end portions Ga and Gb are set at the same position and the inner circumferential blade end portions Ha and Hb are set at different positions in a single blade. However, the positional settings are not limited to these. The outer circumferential blade end portions Ga and Gb may be set at positions different from each other. Alternatively, the inner circumferential blade end portions Ha and Hb may be set at positions different from each other as well as the outer circumferential blade end portions Ga and Gb may be set at positions different from each other.
In Embodiments 2 and 3, a structure in which the transition portion 13c is provided between the deflector opposing blade portion 13a and the air outlet opposing blade portion 13b has been described. Despite this, as illustrated in
In Embodiments 1 to 3, the blades 13 of the both end units 14a out of the individual impeller units each have the two types of shapes, that is, the shape of the deflector opposing blade portion 13a opposite the deflector 18 and the shape of the air outlet opposing blade portion 13b opposing the air outlet 3 in the rotational axis direction AX. However, the shape of the blades 13 of the end units 14a is not limited to these. The support plate 12 between the units may be located at the position of the deflector end surface 18a. For example,
The blade of the fan extension 8a opposite the deflector 18 in the rotational axis direction AX does not necessarily entirely have a shape, with which the wind speed lower than the outlet airflow Ab blown from the blade portion 13b opposing the air outlet 3 can be obtained. That is, it is sufficient that, in the rotational axis direction AX, at least on each of the end sides of the cross flow fan 8, that is, near each of the fan end surface 8b sides of the blade 13 opposite the deflector 18, the blade portion has a shape with which the wind speed lower than that from the air outlet opposing blade portion 13b can be obtained. Since the pressure in the space S formed between each fan end surface 8b and a corresponding one of the side walls 30 is a low pressure space, it is preferable that the stagnation pressure P1 higher than the atmospheric pressure P0 be generated near the space S. Thus, when, at least at the end of the cross flow fan 8 in each fan extension 8a, a portion of the blade 13 near the fan end surface 8b side is the deflector opposing blade portion 13a, the outlet airflow Aa blown from the deflector opposing blade portion 13a impinges upon the deflector 18. Thus, the stagnation pressure P1 is generated in the impinging region E3, and accordingly, the effect of preventing reverse suction of the indoor air is produced. By preventing this reverse suction, turbulence of the airflow can be reduced, and accordingly, scattering of water droplets during cooling operation of the air-conditioning apparatus can be prevented. Thus, the performance of the fan can be improved.
The blade portions 13 opposing the air outlet 3 in the rotational axis direction AX are not necessarily entirely have the blade shape with which the wind speed higher than the outlet wind speed Va blown from the fan extensions 8a can be obtained. That is, referring to
According to the present invention, the deflector 18, upon which the outlet airflow from the fan extension 8a impinges, are provided in the main body of the air-conditioning apparatus, that is, the indoor unit 1 main body. With this structure, the airflow is caused to impinge upon the deflector 18, thereby generating the stagnation pressure P1 (>atmospheric pressure P0). The shape of the deflector opposing blade portion 13a opposite the deflector 18 and the shape of the air outlet opposing blade portion 13b opposing the air outlet 3 are different from each other. For example, the lengths of the chord lines M are different from each other in Embodiment 1, the sizes of the outlet angles α are different from each other in Embodiment 2, and the sizes of the camber angles β are different from each other in Embodiment 3. However, the relationships among the lengths of the chord lines and the sizes of the outlet angles α and the camber angles β are not limited to these. There may be differences in two of the length of the chord line M, the size of the outlet angle α, and the size of the camber angle β between the deflector opposing blade portion 13a and the air outlet opposing blade portion 13b, or there may be differences in all of these length and sizes. It is sufficient that a structure, with which the wind speed Va of the outlet airflow Aa directed toward the deflector 18 be lower than the wind speed Vb of the outlet airflow Ab directed toward the air outlet 3, be realized. The deflector opposing blade portion 13a has the blade shape so that a minimum wind speed required to increase the stagnation pressure P1, which is obtained by the impinging flow, to a pressure higher than the atmospheric pressure P0 can be obtained. Thus, reverse suction can be prevented, and furthermore, the energy loss can be reduced as well as noise can be reduced. In addition, the air outlet opposing blade portion 13b has the blade shape, with which the wind speed Vb of the outlet airflow Ab blown from the air outlet 3, the wind speed Vb being higher than the wind speed Va of the outlet airflow Aa blown from the deflector opposing blade portion 13a, can be obtained. Thus, the air volume can be increased by the entirety of the fan so as to improve the performance of the fan, and an air-conditioning apparatus of reduced power consumption can be obtained.
In order to obtain different wind speeds of airflows from the blade shapes of the deflector opposing blade portion 13a and the air outlet opposing blade portion 13b, for example, the blade thicknesses may be different from each other. Here, the blade thickness refers to the width between the positive pressure surface 19 and the negative pressure surface 20 of the blade in a section perpendicular to the rotational axis 17. That is, the blade thickness of the deflector opposing blade portion 13a of the fan extension 8a opposite the deflector 18 is set to be smaller than that of the air outlet opposing blade portion 13b. An air path is larger between the blades having a small blade thickness than between the blades having a large blade thickness. Thus, the speed of an airflow passing between the blades having a small blade thickness is lower than that of an airflow passing between the blades having a large blade thickness. Accordingly, an outlet airflow flowing at the wind speed Va, which is lower than the wind speed Vb of the outlet airflow Ab blown from the air outlet opposing blade portion 13b, can be obtained with the deflector opposing blade portion 13a. In this case, the blade thicknesses are not necessarily different from each other over the entire blade shape from the inner circumferential blade end portion H to the outer circumferential blade end portion G. The effect similar to that obtained in Embodiments 1 to 3 can be obtained when the blade thicknesses are different at least near the outer circumferential blade end portion G, which is a portion that particularly affects airflows directed toward the deflector 18 and the air outlet 3.
The fan extension 8a of the fan 8 opposite the deflectors 18 may include one individual impeller unit, in which the pitch of the blades of the individual impeller unit 14a may be different from that of the blades 13 of the individual impeller unit 14 located in the fan central portion 8c. That is, the deflector opposing blade portions 13a of the fan extension 8a opposite the deflector 18 may be spaced apart from one another by a pitch larger than a pitch by which the blades 13 of the individual impeller unit 14 located in the fan central portion 8c are spaced apart from one another. When the pitch of the deflector opposing blade portions 13a of the fan extension 8a is increased, the speed at which the air flows between the blades is reduced. Thus, in the impinging region E3 opposite the deflector 18, an outlet airflow flowing at a wind speed lower than a wind speed of an outlet airflow blown from the blade 13 in the fan central portion 8c can be obtained.
The fan extension 8a of the fan 8 opposite the deflector 18 may include one individual impeller unit, in which the number of the deflector opposing blade portions 13a of the individual impeller unit 14a may be less than the number of the blades 13 of the individual impeller unit 14 located in the fan central portion 8c. When the number of the deflector opposing blade portions 13a of the fan extension 8a is reduced, energy provided to the airflow is less than that in the fan central portion 8c. Thus, in the impinging region E3 opposite the deflector 18, an outlet airflow flowing at a wind speed lower than the wind speed of the outlet airflow blown from the blade 13 in the fan central portion 8c can be obtained.
In either case, in the fan extension 8a provided at each end of the fan 8, at least the impinging region E3 needs to be in an atmosphere of the stagnation pressure P1 higher than the atmospheric pressure P0 by blowing the outlet airflow flowing at a lower wind speed than the wind speed of the outlet airflow blown from the blade 13 in the fan central portion 8c.
As described above, “to have the blade shapes different from each other” includes the case where there are differences in pitch of the blades, number of the blades, positions at which the blades are secured to the support plate, and the like between the blade shapes in addition to the case where there are differences in shape of the section perpendicular to the rotational axis 17 of the fan, that is, in thickness, chord line M, camber line, outlet angle α, camber angle β, and the like between the blade shapes.
The shape of the deflector 18 is not limited to the shape illustrated in
The deflector 18 may be integrally formed with the rear guide 10 by, for example, resin molding, or may be separately formed from the rear guide 10 and, for example, fitted into the rear guide 10 at each end of the rear guide 10 in the longitudinal direction (rotational axis direction AX). The separately formed deflector 18 is convenient in order to change the shape, width, thickness, or the like in accordance with the capacity or the like of the indoor unit 1.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2011-130031 | Jun 2011 | JP | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2012/002178 | 3/29/2012 | WO | 00 | 11/21/2013 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2012/169100 | 12/13/2012 | WO | A |
| Number | Date | Country |
|---|---|---|
| 50-14006 | Feb 1975 | JP |
| 56-139890 | Oct 1981 | JP |
| 58-122396 | Jul 1983 | JP |
| 02-199297 | Aug 1990 | JP |
| 03-194196 | Aug 1991 | JP |
| 04-190023 | Jul 1992 | JP |
| 04190024 | Jul 1992 | JP |
| 4190024 | Aug 1992 | JP |
| 06-033893 | Feb 1994 | JP |
| 08-319990 | Dec 1996 | JP |
| 2001-201078 | Jul 2001 | JP |
| 2001-207990 | Aug 2001 | JP |
| 2009-250601 | Oct 2009 | JP |
| 2009-250601 | Oct 2009 | JP |
| Entry |
|---|
| Office Action mailed Jul. 3, 2015 in the corresponding CN Patent application No. 201280028437.5 (with English translation). |
| Extended European Search Report mailed Mar. 20, 2015 in the corresponding European Patent application No. 12796903.8. |
| Notification of Reason for Refusal issued from the Japanese Patent Office dated Nov. 1, 2012 for the corresponding Japanese Patent Application No. 2011-130031. (with English translation). |
| Notification of Reason for Rejection issued from the Japanese Patent Office dated Jun. 11, 2013 for the corresponding Japanese Patent Application No. 2011-130031. (with English translation). |
| International Search Report of the International Searching Authority mailed Jun. 5, 2012 for the corresponding international application No. PCT/JP2012/002178. |
| Number | Date | Country | |
|---|---|---|---|
| 20140102676 A1 | Apr 2014 | US |
