Patent Application
20150252816
The present invention relates to a cross-flow fan and particularly a cross-flow fan equipped with blades made of resin.
Cross-flow fans used, for example, in indoor units of air conditioners have two disc-shaped or circular annular support plates that are disposed on both lengthwise direction ends and plural blades that extend in the lengthwise direction and are disposed between the two support plates. Additionally, there are cases where, as described in patent document 1 (Japanese Patent Unexamined Publication No. H05-87086), for example, a disc-shaped or circular annular intermediate plate is disposed between both support plates in order to reinforce the strength of the plural blades.
In this connection, it is described in patent document 1 that, when many support plates are disposed, flow path loss increases because air friction loss ends up occurring due to the plural support plates. However, if the number of support plates is reduced in order to reduce flow path loss caused by the support plates, the strength of the cross-flow fan ends up being reduced.
It is an object of the present invention to reduce flow path loss caused by a support plate or the like without reducing the strength of a cross-flow fan.
A cross-flow fan pertaining to a first aspect of the present invention comprises: a disc-shaped or circular annular support plate; plural blades extending in a lengthwise direction from the support plate; and an auxiliary ring having a ring portion that is positioned on a lengthwise direction intermediate section of the plural blades and is disposed on the outside of outer ends of the plural blades and plural connection portions that extend from the ring portion as far as spaces between adjacent blades of the plural blades and are joined to the blades in the spaces between adjacent blades.
According to the cross-flow fan pertaining to the first aspect, the auxiliary ring is joined to the blades at the connection portions that extend only as far as the spaces between adjacent blades, and thus flow path loss is suppressed, and the circular annular ring portion bundles together the plural blades at the lengthwise direction intermediate section of the plural blades, and thus the strength of a fan block including the support plate and the plural blades is reinforced.
A cross-flow fan pertaining to a second aspect of the present invention is the cross-flow fan pertaining to the first aspect, wherein the plural connection portions of the auxiliary ring are joined to suction surfaces of the plural blades.
According to the cross-flow fan pertaining to the second aspect, the connection portions are joined to the suction surfaces of the blades, and the pressure surface sides of the blades are not used for connection, so connection portions existing on the pressure surface sides of the blades can be reduced.
A cross-flow fan pertaining to a third aspect of the present invention is the cross-flow fan of the second aspect, wherein the plural connection portions of the auxiliary ring are each formed in a substantially triangular shape projecting inward from the ring portion, and one side of each of the connection portions having the substantially triangular shape is joined to the suction surfaces of the blades.
According to the cross-flow fan pertaining to the third aspect, one side of each of the connection portions having the substantially triangular shape is joined to the suction surfaces of the blades, so the joint sections can be enlarged, and in addition the area of the connection portions on the pressure surface side of other blades becomes reduced, so flow path loss that increases due to the connection portions can be kept low.
A cross-flow fan pertaining to a fourth aspect of the present invention is the cross-flow fan of the second aspect or the third aspect, wherein the length of the sections of the auxiliary ring where the connection portions are joined to the suction surfaces of the blades is equal to or less than half of the chord length of the blades.
According to the cross-flow fan pertaining to the fourth aspect, the length of the sections where the connection portions are joined to the suction surfaces of the blades is equal to or less than half of the chord length, so the area that the connection portions occupy in the spaces between adjacent blades can be reduced and the blade surface effective area can be enlarged. In order to reduce flexure of the blades caused by centrifugal force during fan rotation or an external force, it suffices for the outer peripheral side of half of the chord length to be supported by the auxiliary ring.
A cross-flow fan pertaining to a fifth aspect of the present invention is the cross-flow fan of any of the first aspect to the fourth aspect, wherein the ring portion of the auxiliary ring is circular annular, and the radius of the inner periphery of the ring portion is equal to or greater than the distance from the central axis of the cross-flow fan to the outer ends of the blades.
According to the cross-flow fan pertaining to the fifth aspect, by making the radius of the inner periphery of the ring portion equal to or greater than the distance from the central axis to the outer ends of the blades, the flow of air on the central axis side of the inner periphery of the ring portion is no longer obstructed by the ring portion, and it becomes easier for flow path loss to be suppressed.
A cross-flow fan pertaining to a sixth aspect of the present invention is the cross-flow fan of any of the first aspect to the fifth aspect, wherein the auxiliary ring is molded integrally with the plural blades.
According to the cross-flow fan pertaining to the sixth aspect, by molding the auxiliary ring integrally with the plural blades, assembly of the auxiliary ring and the plural blades becomes unnecessary.
A cross-flow fan pertaining to a seventh aspect of the present invention is the cross-flow fan of any of the first aspect to the sixth aspect, wherein the thickness of the ring portion of the auxiliary ring becomes thinner heading from the inner peripheral side toward the outer peripheral side.
According to the cross-flow fan pertaining to the seventh aspect, the thickness of the ring portion becomes thinner heading toward the outer peripheral side, so loss caused by air flow at the auxiliary ring can be reduced.
In the cross-flow fan pertaining to the first aspect of the present invention, the fan block of the cross-flow fan is reinforced by the auxiliary ring, so the blades can be lengthened without reducing the strength of the cross-flow fan, and flow path loss that had conventionally been caused by an intermediate plate or the like is reduced so that flow path loss of the cross-flow fan can be reduced.
In the cross-flow fan pertaining to the second aspect of the present invention, by eliminating the connection portions on the pressure surface sides of the blades, the effective area of the pressure surfaces is increased so that blowing performance can be improved, and the effect of suppressing flow path loss can be enhanced.
In the cross-flow fan pertaining to the third aspect of the present invention, because of the structure wherein one side of each of the connection portions having the triangular shape is joined to the suction surfaces of the blades, the effects of reducing flow path loss of the cross-flow fan and preventing strength from being reduced can be improved at the same time.
In the cross-flow fan pertaining to the fourth aspect of the present invention, the blades are efficiently reinforced and the area that the connection portions occupy in the spaces between adjacent blades is reduced so that flow path loss can be suppressed.
In the cross-flow fan pertaining to the fifth aspect of the present invention, by increasing the distance from the inner periphery to the outer periphery of the ring portion (the width of the ring portion), the strength of the auxiliary ring can be increased while preventing an increase in flow path loss.
In the cross-flow fan pertaining to the sixth aspect of the present invention, assembly of the auxiliary ring and the plural blades becomes unnecessary and costs can be reduced.
In the cross-flow fan pertaining to the seventh aspect of the present invention, loss caused by air flow is reduced so that blowing characteristics can be improved.
A cross-flow fan pertaining to an embodiment of the present invention will be described below taking as an example a cross-flow fan installed in an indoor unit of an air conditioning apparatus.
The indoor heat exchanger 4 is configured as a result of a front surface side heat exchanger 4a and a back surface side heat exchanger 4b being coupled to one another so as to form an inverted V shape as seen in a side view. In a plan view seen from the top surface of the main body casing 2, the front surface side heat exchanger 4a is disposed in a position opposing substantially the front surface side half of the air inlet 2a, and the back surface side heat exchanger 4b is disposed in a position opposing substantially the back surface side half. Both the front surface side heat exchanger 4a and the back surface side heat exchanger 4b are configured by arranging numerous plate fins parallel to one another in the width direction of the indoor unit 1 and attaching them to heat transfer tubes. When the room air that has been sucked in from the air inlet 2a and passed through the air filter 3 travels between the plate fins of the front surface side heat exchanger 4a and the back surface side heat exchanger 4b, heat exchange takes places and air conditioning is performed.
On the downstream of the indoor heat exchanger 4, the substantially cylindrically shaped cross-flow fan 10 extends long along the width direction of the main body casing 2 and is disposed parallel to the width direction of the main body casing 2 together with the indoor heat exchanger 4. The cross-flow fan 10 is equipped with an impeller 20, which is disposed in a space surrounded so as to be sandwiched by the inverted V-shaped indoor heat exchanger 4, and a fan motor (not shown in the drawings) for driving the impeller 20. The cross-flow fan 10 generates an air flow as a result of the impeller 20 being rotated in direction A1 (clockwise) indicated by the arrow in
An outlet passage leading to an air outlet 2b downstream of the cross-flow fan 10 has a back surface side configured by a scroll member 2c. The scroll member 2c has substantially the same width as the open portion of the air outlet 2b in the main body casing 2 as seen in a front view. The upper end of the scroll member 2c is positioned higher than the upper end of the cross-flow fan 10 and, as seen in a side view, is positioned in a location offset toward the back surface side of the central axis of the cylindrical cross-flow fan 10. The lower end of the scroll member 2c is coupled to the open end of the air outlet 2b. A guide surface of the scroll member 2c has, in order to smoothly and quietly guide to the air outlet 2b the air blown out from the cross-flow fan 10, a smoothly curvilinear shape having a center of curvature on the side of the cross-flow fan 10 as seen in a cross-sectional view.
Each fan block 30 is equipped with plural blades 40, a circular annular support plate 50, and an auxiliary ring 60. In the assembly of the impeller 20, the plural blades 40 of one fan block 30 are fused to the support plate 50 of an adjacent fan block 30 or the end plate 21.
The plural blades 40 extend in the lengthwise direction (the direction along the axial center O) from a first surface 50a of the circular annular support plate 50. The blades 40 are molded integrally with the support plate 50, and thus blade base portions 40c are fixed to the first surface 50a of the support plate 50 and the sides of the blades 40 opposite the blade base portions 40c in the lengthwise direction become blade distal end portions 40d. A length L1 of the blades 40 (the dimension from the blade base portions 40c to the blade distal end portions 40d) is, for example, about 10 cm. The blades 40 have suction surfaces 40f and pressure surfaces 40e. When the fan block 30 rotates in direction A1 indicated by the arrow in
Among the plural blades 40, there is just one blade 40 having a cutaway portion 40i formed in the blade distal end portion 40d. The cutaway portion 40i is for positioning two fan blocks 30 or a fan block 30 and the end plate 21, and is a section that fits together with the step portion 23a of the recessed portion 23 of the end plate 21 described above or a step portion 51c of a recessed portion 51 of the fan block 30 described later. Because there is the cutaway portion 40i, the blades 40 and the recessed portions 23 of the end plate 21 or the recessed portions 51 of the fan block 30 can be made to have a one-to-one correspondence with one another in this way. When this positioning is done, the plural blades 40 can be made to correspond by group to plural split molds of a mold at the time of injection molding and the blades 40 can be disposed in such a way that they are easily removed from the split molds. Specifically, the plural blades 40 are disposed in a shape having rotational asymmetry in which the inclination of the blades 40 is changed in the direction in which the blades 40 are removed from the split molds to make them easier to remove compared to a case where the plural blades 40 are disposed so as to have rotational symmetry relative to the axial center O.
An outer periphery 51a of the recessed portions 51 that outer ends 40a of the blades 40 touch is located on the inside of an outer periphery 50c of the support plate 50, and inner ends 51b of the recessed portions 51 that inner ends 40b of the blades 40 touch are located on the outside of an inner periphery 50d. of the support plate 50. In other words, a distance d1 from the center (a point on the axial center O) of the support plate 50 to the outer periphery 51a of the recessed portions 51 (the distance to the outer ends 40a of the blades 40) is smaller than a radius r1 from the center of the support plate 50 to the outer periphery 50c. Furthermore, a distance d2 from the center (a point on the axial center O) of the support plate 50 to the inner ends 51b of the recessed portions 51 (the distance to the inner ends 40b of the blades 40) is larger than a radius r2 from the center of the support plate 50 to the inner periphery 50d. In order to keep high the strength with which the support plate 50 supports the blades 40, a width W1 (radius r1−radius r2) of the support plate 50 is set larger than the radial direction distance (distance d1−distance d2) from the outer ends 40a of the blades 40 to the inner ends 40b.
The auxiliary ring 60 is positioned on the lengthwise direction intermediate section of the blades 40 and is located in a position away from the blade base portions 40c by a distance of 60% of the dimension from the blade base portions 40c to the blade distal end portions 40d (the length L1 of the blades 40). It is preferred that the position where the auxiliary ring 60 is disposed be away from the blade base portions 40c by a distance equal to or greater than 55% of the length L1 in order to improve the strength of the cross-flow fan 20 and facilitate the assembly step such as ultrasonic welding. However, it is not necessary for the position where the auxiliary ring 60 is disposed to be away from the blade base portions 40c by a distance equal to or greater than 55% of the length L1, and it suffices for the auxiliary ring 60 to be positioned on the lengthwise direction intermediate section of the blades 40. As will be understood from the above description, a configuration where the auxiliary ring 60 is located in a position a little offset from the exact middle is also included in the concept of the lengthwise direction intermediate section of the blades 40.
The connection portions 62 are each formed in a triangular shape projecting inward from the ring portion 61 as seen in the direction of the axial center O. The connection portions 62 having the triangular shape each have three vertex portions 62a, 62b, and 62c; the sides between the vertex portions 62a and 62b are connected to the ring portion 61, and the sides between the vertex portions 62a and 62c are connected to the suction surfaces 40f of the blades 40. The connection portions 62 are not connected to the pressure surfaces 40e of the blades 40. A length L4 of the sections where the connection portions 62 are connected to the suction surfaces 40f (the length from the vertex portions 62a to the vertex portions 62c) is shorter than ½ of a chord length L3. By setting the length L4 of the sections connected to the suction surfaces 40f shorter than ½ of the chord length L3, blowing characteristics are improved compared to a case where the length L4 is set longer than ½ of the chord length L3.
The connection auxiliary portions 63 are firmed in the neighborhoods of the outer ends 40a of the blades 40. The connection auxiliary portions 63 are sections filling in the spaces between the outer ends 40a of the blades 40, the connection portions 62, and the ring portion 61, and aid the connection of these three.
In
The thickness of the auxiliary ring 60 becomes thinner heading from the inner peripheral side toward the outer peripheral side. In other words, a thickness t2 of the auxiliary ring 60 at the outer peripheral surface 60c is smaller than a thickness t1 of the auxiliary ring 60 in the neighborhood of the blade base portions 40c. Seen in greater detail, an angle of inclination θ1 with which the first surface 60a of the auxiliary ring 60 intersects a plane perpendicular to the axial center O is set so as to be larger than an angle of inclination θ2 with which the second surface 60b intersects this perpendicular plane. It will be noted that the thickness t1 of the auxiliary ring 60 is set smaller than a thickness t3 of the support plate 50.
(4-1)
In the above-described embodiment, a case was described where one auxiliary ring 60 is disposed on one fan block 30, but plural auxiliary rings 60 may also be disposed on one fan block 30.
(4-2)
In the above-described embodiment, a case was described where the radius r3 of the outer periphery 61a of the ring portion 61 is larger than the radius r1 of the outer periphery 51a of the circular annular support plate 50, but the radius r3 of the outer periphery 61a of the ring portion 61 may also be set the same as the radius r1 of the outer periphery 51a of the support plate 50.
(4-3)
In the above-described embodiment, a case was described where the radius r4 of the inner periphery 61b of the ring portion 61 is slightly larger than the distance d1 to the outer ends 40a of the blades 40, but the radius r4 may also be configured to be equal to the distance d1 so that the inner periphery 61b of the ring portion 61 runs along the outer ends 40a of the blades 40.
(4-4)
In the above-described embodiment, a case was described where the shape of the auxiliary ring 60 is circular annular, but the shape of the auxiliary ring 60 is not limited to being circular annular and may also, for example, be a polygonal shape having the same number of corners as the number of blades 40 or a shape having serrations (numerous indentations) in the outer peripheral end.
(5-1)
As described above, the ring portion 61 of the auxiliary ring 60 is positioned on the lengthwise direction intermediate section of the plural blades 40 and is disposed on the outside of the outer ends 40a of the plural blades 40. Furthermore, the plural connection portions 62 of the auxiliary ring 60 extend from the ring portion 61 as far as spaces between adjacent blades of the plural blades 40 and are joined to the blades 40 in the spaces between adjacent blades. The “spaces between adjacent blades” means, in other words, each region sandwiched between the pressure surface 40e of one blade 40 of the plural blades 40 and the suction surface 40f of the blade 40 adjacent to that blade 40.
The auxiliary ring 60 is joined to the blades 40 at the connection portions 62 that extend only as far as the spaces between adjacent blades, and thus flow path loss is suppressed. At the same time, the circular annular ring portion 61 bundles together the plural blades 40 at the lengthwise direction intermediate section of the plural blades 40, and thus the strength of the fan block 30 including the circular annular support plate 50 and the plural blades 40 is reinforced.
A configuration will be considered where, for example, in order to obtain a block resembling the fan block 30 having the length L1, instead of the auxiliary ring 60, as shown in
It will be noted that, although in the above-described embodiment a case was described where the support plate 50 is circular annular, even if the support plate is disc-shaped it can be formed in the same way as in a case where it is circular annular, and even in a case where a disc-shaped support plate is used, effects that are the same as those in a case where the circular annular support plate 50 is used are achieved.
(5-2)
In the cross-flow fan 10, the connection portions 62 are joined to the suction surfaces 40f of the blades 40 and are not joined to the pressure surfaces 40e of the blades 40. Even when there is the auxiliary ring 60, as the connection portions 62 do not exist on the pressure surfaces 40e of the blades 40 in this way, loss on the side of the pressure surfaces 40e is reduced, so the effect of suppressing flow path loss can be enhanced more than reducing loss on the side of the suction surfaces 40f where pressure is small.
(5-3)
Furthermore, the connection portions 62 are each formed in a triangular shape projecting inward from the ring portion 61. Additionally, one side (the side between the vertex portion 62a and the vertex portion 62c) of each of the connection portions 60 having the triangular shape is joined to the suction surfaces 40f of the blades 40. Because one side of each of the connection portions 62 having the triangular shape is joined to the suction surfaces 40f of the blades 40, the joint sections can be enlarged relative to the area of the connection portions 62. In addition, one of the vertices lies on the pressure surface side of other blades, so flow path loss that increases due to the connection portions can be kept low. Because of this structure, the effects of reducing flow path loss of the cross-flow fan 10 and preventing strength from being reduced can be improved at the same time. The sides of the connection portions 60 between the vertex portions 62a, 62b, and 62c are substantially linear, but each side may also be somewhat irregular.
(5-4)
As shown in
(5-5)
By making the radius r4 of the inner periphery of the ring portion 61 equal to or greater than the distance d1 from the axial center O of the central axis of the cross-flow fan 10 to the outer ends 40a of the blades 40, the flow of air on the central axis side of the inner periphery of the ring portion 61 is no longer obstructed by the ring portion 61. Because of that, it becomes easier for flow path loss to be controlled, and the strength of the auxiliary ring 60 can be increased by increasing the distance from the inner periphery of the ring portion 61 to the outer periphery (the width W2 of the ring portion).
(5-6)
In the cross-flow fan 10 described above, the auxiliary ring 60 and the plural blades 40 are formed of resin, and the auxiliary ring 60 is molded integrally with the plural blades 40 by injection molding, for example. By molding the auxiliary ring 60 integrally with the plural blades, assembly of the auxiliary ring and the plural blades becomes unnecessary and costs can be reduced. Likewise, the support plate 50 is also funned of resin and is molded integrally with the auxiliary ring 60 and the plural blades 40 by injection molding, for example, at the same time as the plural blades 40 and the auxiliary ring 60. For that reason, the effect of reducing costs resulting from reducing the number of assembly steps becomes even greater.
(5-7)
Furthermore, the thickness of the ring portion 61 of the auxiliary ring 60 becomes thinner heading from the inner peripheral side toward the outer peripheral side. In other words, the thickness t1 on the inner peripheral side is larger than the thickness t2 on the outer peripheral side. For that reason, loss caused by air flow at the auxiliary ring 60 can be reduced and blowing characteristics can be improved. Furthermore, it is preferred that the thickness of the auxiliary ring 60 become thinner heading toward the outer peripheral side from the connection portions 62 to the ring portion 61. In this case also, blowing characteristics can be further improved. Moreover, because the thickness of the auxiliary ring 60 is thinner on the outer peripheral side than it is on the inner peripheral side, it becomes easier to remove the fan block 30 of the cross-flow fan 10 from the mold during injection molding.
10 Cross-flow Fan
20 Impeller
30 Fan Block
40 Blades
50 Support Plate
60 Auxiliary Ring
Patent Document 1: Japanese Patent Unexamined Publication No. H05-87086.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-194255 | Sep 2012 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2013/073141 | 8/29/2013 | WO | 00 |
