A cross-flow fan made of resin includes first and second fan blocks joined together. The first fan block includes a first support plate, plural first blades connected to the first support plate, and a first outer peripheral ring having a first ring portion that interconnects outer ends of the plural first blades. The second fan block includes a second support plate, plural second blades having second one-side distal ends connected to the second support plate, and a second outer peripheral ring having a second ring portion that interconnects outer ends of the plural second blades adjacent second other-side distal ends of the plural second blades. The second other-side distal ends of the plural second blades are joined to the first support plate, and the first support plate and the second outer peripheral ring are disposed adjacent to each other.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. National stage application claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2015-215169, filed in Japan on Oct. 30, 2015, the entire contents of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a cross-flow fan and particularly a cross-flow fan equipped with blades made of resin.

BACKGROUND ART

Cross-flow fans used in indoor units of air conditioning systems, for example, have plural blades that extend in the longitudinal direction of the cross-flow fan and are disposed between annular partition plates disposed on both longitudinal direction ends of the cross-flow fan. Additionally, as disclosed in JP-A No. 2014-47772, for example, there are cases where a reinforcement ring is disposed between support plates to reinforce the strength of the plural blades.

SUMMARY

Technical Problem

The cross-flow fan disclosed in JP-A No. 2014-47772 has an auxiliary ring disposed in the longitudinal direction middle section of the blades, but with this configuration also, owing to an increase in the diameter of the fan blocks and a lengthening of the blade length to improve performance in recent years, there is a tendency for shifts to become greater in the positions of the distal ends of the blades of each fan block because of, for example, thermal contraction of the resin when molding the fan blocks. When positional shifts occur in the distal ends of the blades of the fan blocks in this way, not only does it become difficult to align the fan blocks when joining together the fan blocks by ultrasonic welding, for example, and require extra manufacturing time, but alignment of the distal ends of the blades must be forcibly performed, so it becomes easier for torsion to arise in the blades, resulting, for example, in the occurrence of noise and a reduction in blowing performance.

It is a problem of the present invention to provide a cross-flow fan that is inexpensive and has good performance.

Solution to Problem

A cross-flow fan pertaining to a first aspect of the invention is a cross-flow fan that is made of resin and includes a first fan block and a second fan block that are joined together, wherein the first fan block is equipped with a disc-shaped or annular first support plate, plural first blades having first one-side distal ends connected to the first support plate, and a first outer peripheral ring having a first ring portion that interconnects outer ends of the plural first blades in the neighborhood of first other-side distal ends of the plural first blades located on the opposite side of the first one-side distal ends, the second fan block is equipped with a disc-shaped or annular second support plate, plural second blades having second one-side distal ends connected to the second support plate, and a second outer peripheral ring having a second ring portion that interconnects outer ends of the plural second blades in the neighborhood of second other-side distal ends of the plural second blades located on the opposite side of the second one-side distal ends, the second other-side distal ends of the plural second blades are joined to the first support plate, and the first support plate and the second outer peripheral ring are disposed in close proximity to each other.

According to the cross-flow fan pertaining to the first aspect, because the second other-side distal ends of the plural second blades are joined to the first support plate, and the first support plate and the second outer peripheral ring are disposed in close proximity to each other, shifts in the positions of the second other-side distal ends of the plural second blades of the second fan block can be prevented by the second outer peripheral ring, so when aligning the plural second blades and the first support plate there is no longer the need to correct shifts in the positions of the plural second blades that have shifted positions.

A cross-flow fan pertaining to a second aspect of the invention is the cross-flow fan of the first aspect, wherein the first support plate, the plural first blades, and the first outer peripheral ring of the first fan block are integrally molded, and the second support plate, the plural second blades, and the second outer peripheral ring of the second fan block are integrally molded.

According to the cross-flow fan pertaining to the second aspect, because the first support plate, the plural first blades, and the first outer peripheral ring are integrally molded and the second support plate, the plural second blades, and the second outer peripheral ring are integrally molded, the first one-side distal ends of the plural first blades of the first fan block are fixed by the first support plate and the first other-side distal ends are fixed by the first outer peripheral ring, so that it becomes difficult for the first fan block to become deformed. Furthermore, the second one-side distal ends of the plural second blades of the second fan block are fixed by the second support plate and the second other-side distal ends are fixed by the second outer peripheral ring, so that it becomes difficult for the second fan block to become deformed. As a result, the dimensional accuracy of the first fan block and the second fan block when joining together the first fan block and the second fan block is improved.

A cross-flow fan pertaining to a third aspect of the invention is the cross-flow fan of the first aspect or the second aspect, wherein the second other-side distal ends of the plural second blades of the second fan block are positioned in a place where they project toward the opposite side of the second one-side distal ends from the second outer peripheral ring.

According to the cross-flow fan pertaining to the third aspect, because the second other-side distal ends of the plural second blades are positioned in a place where they project toward the opposite side of the second one-side distal ends from the second outer peripheral ring, it becomes possible to ensure that the second outer peripheral ring and first support plate are not joined together while joining together the second other-side distal ends of the plural second blades and the first support plate of the first fan block using ultrasonic welding, for example, the joining together of the first fan block and the second fan block can be performed strongly and inexpensively, and the occurrence of noise can be suppressed by not joining together the second outer peripheral ring and the first support plate.

A cross-flow fan pertaining to a fourth aspect of the invention is the cross-flow fan of any of the first aspect to the third aspect, wherein the first support plate has a down-step portion at which the section of the first support plate corresponding to the second outer peripheral ring is sunken below the section of the first support plate corresponding to the inner peripheral side of the second outer peripheral ring, and the second outer peripheral ring enters the down-step portion, thereby reducing the longitudinal direction thickness with which the first support plate and the second outer peripheral ring lie on top of each other.

According to the cross-flow fan pertaining to the fourth aspect, because the second outer peripheral ring enters the down-step portion of the first support plate, thereby reducing the longitudinal direction thickness with which the first support plate and the second outer peripheral ring lie on top of each other, workability can be improved while suppressing a worsening of air flow resistance caused by the first support plate and the second outer peripheral ring and stopping a worsening of power consumption.

A cross-flow fan pertaining to a fifth aspect of the invention is the cross-flow fan of the fourth aspect, wherein the down-step portion of the first support plate is sunken deeper than the longitudinal direction thickness of the second outer peripheral ring in the longitudinal direction.

According to the cross-flow fan pertaining to the fifth aspect, because the down-step portion of the first support plate is sunken deeper than the longitudinal direction thickness of the second outer peripheral ring in the longitudinal direction, the thickness of the section where the second outer peripheral ring and the first support plate lie on top of each other can be made thin up to the thickness of the first support plate, and a worsening of air flow resistance can be sufficiently suppressed.

A cross-flow fan pertaining to a sixth aspect of the invention is the cross-flow fan of either the fourth aspect or the fifth aspect, wherein the first support plate further has welding ribs that are welded to the second other-side distal ends of the plural second blades, and the welding ribs are formed in such a way as to extend to the down-step portion, with the height of sections of the welding ribs positioned in the down-step portion being lower than the height of sections of the welding ribs on the inner peripheral side of the down-step portion.

According to the cross-flow fan pertaining to the sixth aspect, because the welding ribs are formed in such a way as to extend to the down-step portion, with the height of the sections of the welding ribs positioned in the down-step portion being lower than the height of the sections of the welding ribs on the inner peripheral side of the down-step portion, projection of welding burrs into the down-step portion can be suppressed while strongly connecting the first support plate and the plural second blades to each other by ultrasonic welding.

A cross-flow fan pertaining to a seventh aspect of the invention is the cross-flow fan of any of the first aspect to the sixth aspect, wherein the second outer peripheral ring has an outer radius that is the same as or smaller than an outer radius of the first support plate.

According to the cross-flow fan pertaining to the seventh aspect, because the second outer peripheral ring has the outer radius that is the same as or smaller than the outer radius of the first support plate, in comparison to a case where the outer radius of the second outer peripheral ring is larger than that of the first support plate, the risk of contact with a casing that covers the outer portion of the cross-flow fan, for example, can be suppressed.

A cross-flow fan pertaining to an eighth aspect of the invention is the cross-flow fan of any of the first aspect to the seventh aspect, wherein the second outer peripheral ring further has reinforcement ribs that are connected to negative pressure surfaces of the plural second blades but are not connected to pressure surfaces of the plural second blades.

According to the cross-flow fan pertaining to the eighth aspect, because the second outer peripheral ring has the reinforcement ribs that are connected to the negative pressure surfaces of the plural second blades but are not connected to the pressure surfaces of the plural second blades, the ability to withstand external force applied to the second blades can be enhanced.

A cross-flow fan pertaining to a ninth aspect of the invention is the cross-flow fan of any of the fourth aspect to the sixth aspect, wherein the first support plate further has thinned portions provided in such a way as not to not reach the down-step portion.

According to the cross-flow fan pertaining to the ninth aspect, because the first support plate has the thinned portions provided in such a way as not to reach the down-step portion, the cross-flow fan can be made lighter while maintaining its strength, and the second blades can be strongly connected to the first support plate by ultrasonic welding, for example.

Advantageous Effects of Invention

In the cross-flow fan pertaining to the first aspect of the invention, a cross-flow fan that is inexpensive, because time and effort when manufacturing the cross-flow fan are saved, can be provided, and a cross-flow fan that has good performance, because a reduction in the performance of the cross-flow fan caused by shifts in the positions of the second other-side distal ends of the second blades is suppressed, can be provided.

In the cross-flow fan pertaining to the second aspect of the invention, the accuracy of the alignment between the first fan block and the second fan block can be improved.

In the cross-flow fan pertaining to the third aspect of the invention, it becomes easy to provide a cross-flow fan that is strong and inexpensive, has good performance, and in which there is little noise.

In the cross-flow fan pertaining to the fourth aspect of the invention, high performance can be realized inexpensively.

In the cross-flow fan pertaining to the fifth aspect of the invention, a cross-flow fan that is inexpensive and has a sufficiently high performance can be provided.

In the cross-flow fan pertaining to the sixth aspect of the invention, a reduction in the performance of the cross-flow fan caused by welding burrs can be prevented.

In the cross-flow fan pertaining to the seventh aspect of the invention, the risk of deformation of and damage to the second outer peripheral ring can be suppressed.

In the cross-flow fan pertaining to the eighth aspect of the invention, a cross-flow fan that is inexpensive and sturdy can be provided.

In the cross-flow fan pertaining to the ninth aspect of the invention, a cross-flow fan that is sturdy and light can be inexpensively provided.

DESCRIPTION OF EMBODIMENT

A cross-flow fan pertaining to an embodiment of the invention will be described below using, as an example, a cross-flow fan installed in an indoor unit of an air conditioning system.

(1) Cross-Flow Fan Inside Indoor Unit

FIG. 1is a drawing showing a general overview of a cross section of an indoor unit1of an air conditioning system. The indoor unit1is equipped with a body casing2, an air filter3, an indoor heat exchanger4, a cross-flow fan10, vertical flaps5, and a horizontal flap6. As shown inFIG. 1, the air filter3is disposed on the downstream side of, and opposing, an air inlet2ain the top surface of the body casing2. The indoor heat exchanger4is disposed further downstream of the air filter3. Room air that travels through the air inlet2aand reaches the indoor heat exchanger4all travels through the air filter3and has dirt and dust removed therefrom.

The indoor heat exchanger4is configured by a front-side heat exchanger4aand a back-side heat exchanger4bthat are coupled to each other 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 body casing2, the front-side heat exchanger4ais disposed in a position opposing the substantially front half of the air inlet2a, and the back-side heat exchanger4bis disposed in a position opposing the substantially back half of the air inlet2a. Both the front-side heat exchanger4aand the back-side heat exchanger4bare configured by lining up numerous plate fins parallel to the width direction of the indoor unit1and attaching them to heat transfer tubes. When the room air that has been sucked in from the air inlet2aand has traveled through the air filter3passes between the plate fins of the front-side heat exchanger4aand the back-side heat exchanger4b, heat exchange takes place and air conditioning is performed.

On the downstream side of the indoor heat exchanger4, the cross-flow fan10, which is shaped substantially like an open cylinder, extends longly along the width direction of the body casing2and, together with the indoor heat exchanger4, is provided parallel to the width direction of the body casing2. The cross-flow fan10is equipped with an impeller20, which is disposed in a space surrounded in such a way as to be sandwiched by the inverted V-shaped indoor heat exchanger4, and a fan motor (not shown in the drawings), which is for driving the impeller20. The cross-flow fan10generates an airflow by rotating the impeller20in direction A1(a clockwise direction) indicated by the arrow inFIG. 1.

An outgoing air passage leading to an air outlet2bdownstream of the impeller20of the cross-flow fan10has a back surface side configured by a scroll member2c. The scroll member2chas a width that is substantially the same as that of the open portion of the air outlet2bin the body casing2as seen in a front view. The upper end of the scroll member2cis positioned higher than the upper end of the impeller20and, as seen in a side view, is positioned in a place offset more toward the back surface side than a central axis of the open cylinder-shaped impeller20. The lower end of the scroll member2cis coupled to the open end of the air outlet2b. A guide surface of the scroll member2cexhibits a smoothly curved shape having a center of curvature on the side of the cross-flow fan10as seen in a cross-sectional view in order to smoothly and quietly guide to the air outlet2bthe air blown out from the impeller20.

(2) General Structure of Impeller of Cross-Flow Fan

InFIG. 2is shown the general structure of the impeller20of the cross-flow fan10. The impeller20is, for example, configured to include two end plates21and24and nine fan blocks30. The end plate21is disposed on one end of the impeller20and has, on a central axis O, a rotating shaft22made of metal. Additionally, normally a boss portion25connected to a fan motor shaft (not shown in the drawings) is provided in the central portion of the end plate24disposed on the other end of the impeller20and to which blades40and an outer peripheral ring60are attached. Alternatively, there are also cases where the end plate24disposed on the other end of the impeller20has another configuration, such as one where the end plate24is configured to have a member linked to part of the fan motor and to have a metal shaft in its central portion. The rotating shaft22of the end plate21and the boss portion25of the end plate24on the other end of the impeller20are supported, and the impeller20rotates about the central axis O.

As shown inFIG. 3, each fan block30is equipped with plural blades40, an annular support plate50, and an outer peripheral ring60. In assembling the impeller20, each fan block30has its own plural blades40welded to the support plate50of the adjacent fan block30or the end plate21. One-side distal ends41of the blades40are connected to the support plate50, and other-side distal ends42of the blades40become welded.

InFIG. 4andFIG. 5are shown two fan blocks that are disposed adjacent to each other and become welded to each other. InFIG. 4andFIG. 5, one fan block30will be called a first fan block301and the other fan block30will be called a second fan block302. Furthermore, the support plate50of the first fan block301will be called a first support plate501, the blades40of the first fan block301will be called first blades401, and the outer peripheral ring60of the first fan block301will be called a first outer peripheral ring601. Moreover, the support plate50of the second fan block302will be called a second support plate502, the blades40of the second fan block302will be called second blades402, and the outer peripheral ring60of the second fan block302will be called a second outer peripheral ring602. Furthermore, a ring portion61that the first outer peripheral ring601has will be called a first ring portion611and reinforcement ribs62that the first outer peripheral ring601has will be called first reinforcement ribs621, and a ring portion61that the second outer peripheral ring602has will be called a second ring portion612and reinforcement ribs62that the second outer peripheral ring602has will be called second reinforcement ribs622. It will be noted that the one-side distal ends41of the first blades401are first one-side distal ends411and that the other-side distal ends42of the first blades401are first other-side distal ends421. Furthermore, the one-side distal ends41of the second blades402are second one-side distal ends412and the other-side distal ends42of the second blades402are second other-side distal ends422.

When the first fan block301and the second fan block302shown inFIG. 4andFIG. 5are joined together, the first support plate501of the first fan block301and the second other-side distal ends422of the plural second blades402of the second fan block302are welded together by ultrasonic waves. Namely, the two fan blocks30adjacent to each other can be viewed in such a way that the second fan block302is the one having the other-side distal ends42of the blades40that become welded and the first fan block301is the one having the support plate50that becomes welded.

(3) Detailed Configuration of Fan Blocks

The fan blocks30pertaining to the present embodiment each comprise the plural blades40, the support plate50, and the outer peripheral ring60, which are integrally molded by injection molding, for example, using a thermoplastic resin as the main material. InFIG. 6is shown a cross section where the fan block30is cut by line I-I ofFIG. 3. Namely, the cross section shown inFIG. 6is a cross section that appears when the fan block30is cut by a plane perpendicular to the central axis O. The rotational direction of the fan block30is direction A1indicated by the arrow inFIG. 6.

The plural blades40extend in the longitudinal direction (the direction along the central axis O) from a first surface51of the annular support plate50. Both outer ends40aand inner ends40bof the blades40shown inFIG. 6form edges parallel to the central axis O. The one-side distal ends41of the blades40are fixed to the first surface51of the support plate50as a result of the blades40being molded integrally with the support plate50(seeFIG. 3). The other-side distal ends42are on the opposite side of the one-side distal ends41of the blades40in the longitudinal direction of the blades40.

The blades40each have a negative pressure surface43and a pressure surface44. As shown inFIG. 6, both the negative pressure surfaces43and the pressure surfaces44curve in the same direction, so the cross section of each blade40as cut by a plane perpendicular to the central axis O is shaped like a crescent moon. When the fan block30rotates in direction A1indicated by the arrow inFIG. 6, the pressure on the pressure surface44sides of the blades40becomes higher while the pressure on the negative pressure surface43sides becomes lower. The number of blades40disposed in each fan block30is thirty-five. If the blades40were disposed so as to have rotational symmetry, the angle formed by two mutually adjacent straight lines out of the thirty-five straight lines joining the outer ends40aof the blades40to the central axis O in a plane perpendicular to the central axis O, for example, would be about 10.3 degrees. However, in each fan block30, the angle formed by these is set to vary from about 8 degrees to about 12 degrees. Namely, this means that the plural blades40are disposed so as to have rotational asymmetry. In this way, by disposing the plural blades40in a shape that does not have rotational symmetry, compared to disposing the plural blades40so as to have rotational symmetry with respect to the central axis O, the inclination of the blades40in the direction in which the blades40detach from a split mold—which is a mold for molding the fan block30—is changed and it is easier to remove the fan block30.

Among the plural blades40is one blade40having a cutout portion (not shown in the drawings) formed in its other-side distal end42. The cutout portion is for positioning the first support plate501of the first fan block301and the plural second blades402of the second fan block302. Because the cutout portion is there, it becomes easy to position the plural second blades402, which are disposed so as to have rotational asymmetry as described above, and the first support plate501.

(3-2) Support Plate

InFIG. 7is shown a state in which the annular support plate50is seen from the side of a second surface52located on the opposite side of the first surface51. Furthermore, inFIG. 8is shown an enlargement of part ofFIG. 7. The second surface52of the support plate50is not flat. In the second surface52of the support plate50, recess portions53, into which the other-side distal ends42of the blades40fit, are formed in the same number as the plural blades40. The recess portions53each have a planar shape that is slightly larger than the cross-sectional shape of the blades40, so when two fan blocks30are laid on top of each other, the blades40fit into the recess portions53.

In the second surface52of the support plate50, a down-step portion55is formed along an outer periphery50aof the support plate50. A cross section along line II-II ofFIG. 8is shown inFIG. 9. A thickness D2of the down-step portion55is thinner than a thickness D1of the section of a principal plane54occupying most of the second surface52. For example, whereas the thickness D1is about 2.5 mm, the thickness D2is about 1 mm. Furthermore, for example, in the support plate50where a radius r1of the outer periphery50ais about 50 mm, a width W1of the down-step portion55is set to about 2 mm to about 3 mm from the outer periphery50a. It will be noted that a radius r2of an inner periphery50bof the support plate50is about 40 mm, for example.

A cross section along line ofFIG. 8is shown inFIG. 10. Furthermore, a cross section along line IV-IV ofFIG. 8is shown inFIG. 11. Welding ribs56shown inFIG. 10andFIG. 11are formed within the recess portions53of the second surface52. The welding ribs56are formed in such a way that a height H2of outer peripheral sections56athat are in the range of the width W1of the down-step portion55is lower than a height H3of inner peripheral sections56blocated on the inner periphery50bside of the width W1of the down-step portion55. Furthermore, a width W2of the outer peripheral sections56aof the welding ribs56is formed smaller than a width W3of the inner peripheral sections56b. The welding ribs56are sections that melt, become integrated with the other-side distal ends42of the blades40, and solidify when the support plate50and the blades40are welded together. The inner peripheral sections56bof the welding ribs56are set in such a way that a high welding strength is obtained by setting their height H3and width W3larger to thereby increase the volume of the welding ribs56. At the same time, by setting the height H2of the outer peripheral sections56aof the welding ribs56lower in comparison to the height H3of the inner peripheral sections56b, welding burrs made of melted parts of the welding ribs56can be suppressed from sticking out between the support plate50and the outer peripheral ring60. Moreover, by setting the width W2of the outer peripheral sections56aof the welding ribs56smaller in comparison to the width W3of the inner peripheral sections56b, the volume per unit length of the welding ribs56becomes smaller, so the effect of suppressing welding burrs made of melted parts of the welding ribs56from sticking out between the support plate50and the outer peripheral ring60is further enhanced.

Outer ends53aof the recess portions53of the support plate50are located on the inner side of the outer periphery50aof the support plate50. Consequently, a distance L1from the center of the support plate50(a point on the central axis O) to the outer ends53aof the recess portions53is smaller than the radius r1of the outer periphery50abut is the same as or slightly larger than a distance L3from the central axis O to the outer ends40aof the blades40. Inner ends53bof the recess portions53of the support plate50are located on the outer side of the inner periphery50bof the support plate50. Consequently, a distance L2from the center of the support plate50to the inner ends53bof the recess portions53is larger than the radius r2of the inner periphery50bbut is slightly smaller than a distance L4from the central axis O to the inner ends40bof the blades40. In this way, because the radius r1of the outer periphery50aof the support plate50is set larger than the distance L3between the outer ends40aof the blades40and the central axis O, and the radius r2of the inner periphery50bof the support plate50is set smaller than the distance L4between the inner ends40bof the blades40and the central axis O, the strength with which the support plate50supports the blades40becomes greater.

In the principal plane54of the support plate50, thinned portions57are formed between adjacent recess portions53. InFIG. 12is shown a cross section of the support plate50along line V-V ofFIG. 7. A thickness D3of the thinned portions57is, for example, about 1 mm thinner than the thickness D1of the principal plane54. In this way, because the thickness D3of the thinned portions57is thinner than the thickness D1of the principal plane54, the material resin can be reduced and the weight of the fan blocks30is reduced. However, because the down-step portion55is formed in the support plate50, if the thinned portions57and the down-step portion55were to connect to each other, this would lead to a reduction in the strength of the support plate50. Therefore, outer walls58are formed on the outer peripheral sides of the thinned portions57to ensure that the thinned portions57and the down-step portion55do not connect to each other. Because the outer walls58are formed, an ultrasonic welding horn can be brought into contact with the inner radial side neighborhood of the down-step portion55, and up to the outer ends40aof the blades40can be sufficiently welded.

(3-3) Outer Peripheral Ring

InFIG. 6is shown the cross-sectional shape of the section where the outer peripheral ring60and the blades40are joined together. The outer peripheral ring60is equipped with the ring portion61and the reinforcement ribs62. A radius r3of an outer periphery61aof the ring portion61is set the same as the radius r1of the outer periphery50aof the support plate50. Furthermore, the radius r3of the outer periphery61aof the ring portion61is larger than the distance L3from the central axis O of the outer peripheral ring60to the outer ends40aof the blades40. That is, the outer periphery61aof the ring portion61runs along the outer side of the outer ends40aof all the blades40. Furthermore, a radius r4of an inner periphery61bof the ring portion61of the outer peripheral ring60is greater than the radius r2of the inner periphery50bof the support plate50and slightly greater than the distance L3to the outer ends40aof the blades40, and the inner periphery61bof the ring portion61runs along the neighborhood of the outer side of the outer ends40aof the blades40.

As shown inFIG. 6, the reinforcement ribs62each have a triangular cross-sectional shape that projects inward from the ring portion61. The triangular reinforcement ribs62each have three vertex portions62a,62b, and62c; the sides between the vertex portions62aand62bare connected to the ring portion61, and the sides between the vertex portions62aand62care connected to the negative pressure surfaces43of the blades40. At the same time, the reinforcement ribs62are not connected to the pressure surfaces44of the blades40. The length of the sections where the reinforcement ribs62are connected to the negative pressure surfaces43(the length between the vertex portions62aand the vertex portions62c) is shorter than ½ of a chord length L5. Here, the chord length L5is the length from the outer ends40ato the inner ends40bof the blades40. By setting the length of the sections connected to the negative pressure surfaces43shorter than ½ of the chord length L5, blowing characteristics are improved in comparison to a case where the length of the sections connected to the negative pressure surfaces43is set longer than ½ of the chord length L5. Moreover, it is preferred that the length of the sections of the reinforcement ribs62connected to the negative pressure surfaces43be shorter than ⅓ of the chord length L5in order to improve blowing characteristics.

InFIG. 13andFIG. 14is shown a state in which the first fan block301and the second fan block302become joined together. InFIG. 15is schematically shown an enlargement of the structure in the vicinity of the first support plate501of the first fan block301and the second outer peripheral ring602of the second fan block302. The second outer peripheral ring602is provided in the neighborhood of the second other-side distal ends422of the second blades402. More specifically, the second other-side distal ends422of the second blades402project toward the opposite side of the second one-side distal ends412from the second outer peripheral ring602. A length L6to which the second other-side distal ends422project is longer than a thickness D4from the bottom surfaces of the recess portions53of the first support plate501to the upper surface of the down-step portion55. Because of this structure, even when the second other-side distal ends422of the second blades402of the second fan block302are welded by ultrasonic welding to the bottom surfaces of the recess portions53of the first support plate501, the second outer peripheral ring602and the first support plate501come into close proximity to each other but do not contact each other. Here, the second outer peripheral ring602and the first support plate501are in close proximity to each other such that the gap between them is smaller than 1 mm. Furthermore, it is preferred that the second outer peripheral ring602and the first support plate501be in close proximity to each other such that the gap between them is smaller than 0.5 mm. When ultrasonically welded, the welding ribs56inFIG. 15melt and become integrated with the second outer peripheral ring602and the first support plate501.

Furthermore, a depth D5from the principal plane54of the first support plate501to the upper surface of the down-step portion55is larger than a thickness D6of the second outer peripheral ring602. In other words, this means that, in the longitudinal direction of the cross-flow fan10, the down-step portion55is sunken deeper than the thickness D6of the second outer peripheral ring602. Because of this structure, even when the second outer peripheral ring602is provided, in the longitudinal direction of the cross-flow fan10, the second outer peripheral ring602and the first support plate501fall in the range of the thickness D1of the first support plate501.

In order for the second outer peripheral ring602to fit the confines of the recess portions53of the first support plate501, the width (r3-r4) of the second ring portion612of the second outer peripheral ring602is set smaller than the width W1of the down-step portion55. Furthermore, in order for the triangular second reinforcement ribs62of the second outer peripheral ring602to fit within the down-step portion55, widened portions55acorresponding to the triangular shapes of the second reinforcement ribs622are formed in the down-step portion55. The width of the widened portions55ais larger than the width W1.

As shown inFIG. 13andFIG. 14, the first fan block301and the second fan block302that have not yet been joined together are stacked on top of each other and installed on top of a jig103(seeFIG. 16). The first fan block301and the second fan block302that have been stacked on top of each other are sandwiched between the jig103and an ultrasonic welding horn102, and the first fan block301is supported from its periphery and fixed (not shown in the drawings). Ultrasonic waves are supplied from a transducer101to the ultrasonic welding horn102, and the supplied ultrasonic waves travel through the ultrasonic welding horn102and become applied to the second fan block302. Because of this, the second blades402of the second fan block302and the first support plate501of the first fan block301become welded to each other by the ultrasonic waves. Because the recess portions53of the first support plate501of the first fan block301each have a planar shape that is slightly larger than the cross-sectional shape of the corresponding second blades402as has already been described, the second blades402fit into and become mated with the recess portions53. Among the recess portions53is formed one recess portion53swhose length is largely different from others. Positioning becomes easier by virtue of this recess portion53sand the corresponding second blade402being formed.

As shown inFIG. 17A, in a conventional fan block930, there has not been an outer peripheral ring in the neighborhood of other-side distal ends942of blades940, so when the plural blades940and a support plate950have been integrally molded by injection molding, sink marks arise and stress in the directions indicated by the arrows occurs starting after the injection of the resin in the injection molding. Because of this stress, a diameter φ1of a circumference on which outer ends940aof the blades940in the neighborhood of the other-side distal ends942are disposed becomes smaller with respect to a diameter φ2of a circumference on which the outer ends940aof the blades940in the neighborhood of one-side distal ends941of the blades940are disposed. Because the diameter φ1becomes smaller, for example, there has arisen the need to align the blades940using a jig or to align the blades940by manual labor. When it has become necessary to align the blades940using a jig or to align the blades940by manual labor, it has been difficult to align the fan block930using a robot arm, for example, and it has been difficult to automate using a robot arm. Furthermore, in order to reduce as much as possible deformation of the resin during the injection molding, the fan block must be sufficiently cooled and then removed, and the amount of time for one shot of injection molding has become longer.

As shown inFIG. 17B, in the above described fan block30, the outer peripheral ring60is provided in the neighborhood of the other-side distal ends42of the blades40, so when the plural blades40and the support plate50have been integrally molded by injection molding, the same sink marks arise and the same stress occurs in the directions of the arrows. However, the outer peripheral ring60works with respect to this stress to prevent deformation of the fan block30, and deformation of the fan block30is suppressed. Because of the working of the outer peripheral ring60, a diameter φ3of a circumference on which the outer ends40aof the blades40in the neighborhood of the other-side distal ends42are disposed can be prevented from becoming smaller with respect to the diameter φ2of the circumference on which the outer ends40aof the blades40in the neighborhood of the one-side distal ends41of the blades40are disposed. As a result, a robot arm, for example, can be used to align the first fan block301and the second fan block302, so that the joining together of the first fan block301and the second fan block302can be automated. Furthermore, the amount of cooling time during the injection molding can be shortened, and the amount of time for one shot during the injection molding can be remarkably shortened in comparison to the fan block930shown inFIG. 17A.

(4) Example Modifications

In the above embodiment, a case was described where the radius r3of the outer periphery61aof the ring portion61was the same as the radius r1of the outer periphery50aof the annular support plate50, but the radius r3of the outer periphery61aof the ring portion61may also be set smaller than the radius r1of the outer periphery50aof the support plate50.

In the above embodiment, a case was described where the radius r4of the inner periphery61bof the ring portion61was slightly larger than the distance L3from the central axis O to the outer ends40aof the blades40, but the radius r4may also be configured to be equal to the distance L3so that the inner periphery61bof the ring portion61is tangential to the outer ends40aof the blades40.

In the above embodiment, a case was described where the shape of the outer peripheral ring60was annular, but the shape of the outer peripheral ring60is not limited to being annular and, for example, may also be a polygonal shape having the same number of angles as the number of blades40, and may also be a shape having serrations (numerous notches) made in its outer peripheral end.

As described above, in the cross-flow fan10, the second other-side distal ends422of the plural second blades402of the second fan block302are joined to the first support plate501of the first fan block301by ultrasonic welding, and the first support plate501and the second outer peripheral ring602are disposed in close proximity to each other. Because the cross-flow fan10is configured in this way, shifts in the positions of the second other-side distal ends422of the plural second blades402of the second fan block302can be prevented by the second outer peripheral ring602, so when aligning the plural second blades402and the first support plate501there is no longer the need to correct shifts in the positions of the plural second blades402. In this way, the cross-flow fan10that is inexpensive, because time and effort when manufacturing the cross-flow fan10are saved, can be provided, and the cross-flow fan10that has good performance, because a reduction in the performance of the cross-flow fan10caused by shifts in the positions of the second other-side distal ends422of the second blades402of the second fan block302is suppressed, can be provided.

It will be noted that although in the above embodiment a case was described where the first support plate501and the second support plate502were annular, even if the first support plate501and the second support plate502are disc-shaped, they can be formed in the same way as in the case where they are annular, and even in the case of using disc-shaped support plates, the same effects as in the case of using the annular first support plate501and second support plate502are achieved.

In the cross-flow fan10, the first support plate501, the plural first blades401, and the first outer peripheral ring601are integrally molded by injection molding. Likewise, the second support plate502, the plural second blades402, and the second outer peripheral ring602are integrally molded by injection molding. Because of this integral molding, the first one-side distal ends411of the plural first blades401of the first fan block301are fixed by the first support plate501and the first other-side distal ends421are fixed by the first outer peripheral ring601, so that it becomes difficult for the first fan block301to become deformed. Furthermore, the second one-side distal ends412of the plural second blades402of the second fan block302are fixed by the second support plate502and the second other-side distal ends422are fixed by the second outer peripheral ring602, so that it becomes difficult for the second fan block302to become deformed. As a result, the dimensional accuracy of the first fan block301and the second fan block302when joining together the first fan block301and the second fan block302is improved. As a result, the accuracy of the alignment between the first fan block301and the second fan block302can be improved. For example, when handling the first fan block301and the second fan block302with robot arms or suction pads, even when stress acts from the robot arms or the suction pads on these, deformation of the first fan block301and the second fan block302can be suppressed, so automation can be easily carried out because of the improvement in alignment accuracy.

Because the second other-side distal ends422of the plural second blades402are positioned in a place where they project toward the opposite side of the second one-side distal ends412from the second outer peripheral ring602, it becomes possible to ensure that the second outer peripheral ring602and the first support plate501are not joined together while joining together the second other-side distal ends422of the plural second blades402and the first support plate501of the first fan block301using ultrasonic welding, for example. As a result, the joining together of the first fan block301and the second fan block302can be performed strongly and inexpensively, the occurrence of noise can be suppressed by not joining together the second outer peripheral ring602and the first support plate501, and the cross-flow fan10that is inexpensive, has good performance, and in which there is little noise can be provided.

The second outer peripheral ring602enters the down-step portion55of the first support plate501, thereby reducing the longitudinal direction thickness in which the first support plate501and the second outer peripheral ring602lie on top of each other. As a result, workability can be improved while suppressing a worsening of air flow resistance caused by the first support plate501and the second outer peripheral ring602and stopping a worsening of power consumption, and at the same time high performance can be realized inexpensively.

Because the down-step portion55of the first support plate501is sunken deeper than the longitudinal direction thickness D6of the second outer peripheral ring602in the longitudinal direction, the thickness of the section where the second outer peripheral ring602and the first support plate501lie on top of each other can be made thin up to the thickness D1of the first support plate501. As a result, a worsening of air flow resistance can be sufficiently suppressed, so the cross-flow fan10that is inexpensive and has a sufficiently high performance can be provided.

Furthermore, in the cross-flow fan10, the welding ribs56are formed in such a way as to extend to the down-step portion55, with the height H2of the outer peripheral sections56apositioned in the down-step portion55being formed lower than the height H3of the inner peripheral sections56blocated on the inner peripheral side of the down-step portion55. Because the welding ribs56have this structure, projection of welding burrs into the down-step portion55can be suppressed while strongly connecting the first support plate501and the plural second blades402to each other by ultrasonic welding, and a reduction in the performance of the cross-flow fan10caused by welding burrs that have entered between the first support plate501and the second outer peripheral ring602and so forth can be prevented.

Because the second outer peripheral ring602of the cross-flow fan10has the radius r3of the outer periphery61a(the outer radius of the second outer peripheral ring602) that is the same as or smaller than the radius r1of the outer periphery50aof the first support plate501(the outer radius of the first support plate501), in comparison to a case where the outer radius of the second outer peripheral ring602is larger than that of the first support plate501, the risk of contact with a casing that covers the outer portion of the cross-flow fan10, for example, can be suppressed, and the risk of deformation of and damage to the second outer peripheral ring602can be suppressed.

Because the second outer peripheral ring602has the second reinforcement ribs622which are reinforcement ribs that are connected to the negative pressure surfaces43of the plural second blades402but are not connected to the pressure surfaces44of the plural second blades402, the ability to withstand external force applied to the second blades402can be enhanced. As a result, a cross-flow fan that is inexpensive, sturdy, and includes the first fan block301and the second fan block302suited to manufacturing automation, for example, can be provided.

Because the first support plate501has the thinned portions57provided in such a way as not to reach the down-step portion55, the cross-flow fan10can be made lighter while maintaining its strength, and the second blades402can be strongly connected to the first support plate501by ultrasonic welding, for example. As a result, the cross-flow fan10that is sturdy and light can be inexpensively provided.

REFERENCE SIGNS LIST

CITATION LIST

Patent Literature