1. Field of The Invention
The present invention relates to a cross flow fan, preferably of an indoor unit of an air conditioner, provided with fan blades having an improved shape.
2. Related Art
An air conditioner has an indoor unit and an outdoor unit, and many of the indoor units are generally provided with cross flow fans.
Such cross flow fan in a prior art is provided with a plurality of fan blades each having a cross sectional shape shown in
However, in such structure of the cross fan blade, in a case where an air suctioning port of the cross flow fan becomes high load state due to influence of a heat exchanger and a suction filter, it tends to increase an air blasting noise and increase a load to be applied on a fan driving motor, thus deteriorating an operational performance of the air conditioner itself.
The present invention was therefore conceived in consideration of the above matters encountered in the prior art, and an object of the present invention is to provide a cross flow fan particularly of an indoor unit of an air conditioner capable of being operated at a low noise even in a high load operation, reducing a load to be applied to a fan driving motor and realizing a highly efficient performance of an air conditioner provided with such cross flow fan.
This and other objects can be achieved according to the present invention by providing, in one aspect, a cross flow fan comprising:
a pair of disc-shaped end plates; and
a plurality of fan blades attached to the end plates in a ring-shaped arrangement, wherein each of the fan blades has a cross sectional area ratio of Sa/Sb in a range of 1.3 to 1.6, preferably, 1.4 to 1.5, in which Sa is a sectional area of a fan outer peripheral side half portion of the blade and Sb is a sectional area of a fan inner peripheral side half portion of the blade at a time when the fan blade is cut perpendicularly with respect to a longitudinal direction of the fan blade and divided into two sectional areas along a central division line in a blade chord direction.
In a second aspect of the present invention, there is provided a cross flow fan comprising:
a pair of disc-shaped end plates; and
a plurality of fan blades attached to the end plates in a ring-shaped arrangement, wherein each of the fan blades has a dimensional ratio of Rb/Ra in a range of 0.1 to 0.8, in which Ra is a dimension of a fan inner peripheral side tip end R-portion of the blade and Rb is a dimension of a fan outer peripheral tip end R-portion of the blade at a time when the fan blade is cut perpendicularly with respect to a longitudinal direction of the fan blade and divided into two sectional areas along a central division line in a blade chord direction.
In a third aspect, there is also provided a cross flow fan comprising:
a pair of disc-shaped end plates; and
a plurality of fan blades attached to the end plates in a ring-shaped arrangement, wherein each of the fan blades has a central portion in a blade chord direction at which the fan blade has a most thickened portion in section when the fan blade is cut perpendicularly with respect to a longitudinal direction of the fan blade and divided into two sectional areas by the central portion in the blade chord direction.
In the above aspect, the cross flow fan may be further provided with at least one disc shaped partition plate which is disposed between the end plates and to which the fan blades are attached in a ring shaped arrangement.
Furthermore, a cross flow fan having a combined structure of the above first to three aspects may be further preferably provided.
According to the cross flow fan of the present invention of the characters mentioned above, when incorporated into an indoor unit of, for example, an air conditioner, air flow noise can be effectively reduced and a load to be applied to a motor for driving the fan can be also reduced, thus providing a high operational efficiency of the air conditioner.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.
In the accompanying drawings:
Preferred embodiments of the present invention of a cross flow fan assembled, for example, in an indoor unit of an air conditioner will be described hereunder with reference to the accompanying drawings.
With reference to
Between the end plates 2a and 2b, a plurality of, or at least one of, ring-shaped (disc-shaped) partition plates 4, seven in
Next, FIGS. 3 to 5 shows the fan blade 3 cut perpendicularly in its longitudinal direction, and the cross sectional area of the fan blade 3 is divided into two parts 3i (fan inner peripheral side) and 3o (fan outer peripheral side) at its central portion in the blade chord length by a chain-dot central division line L.
According to the present invention, as shown in
Furthermore, as shown in
Moreover, as shown in
According to the cross flow fan of the structures mentioned above, when the fan blade 3 is divided equally at the central portion thereof in its chord length direction, the sectional areas of both divided half portions provide the steam-line shapes asymmetric with each other. Therefore, the peel-off phenomenon to the upper surface portion of the fan blade 3 due to the air flow can be suppressed, and in addition, since the area ratio Sa/Sb of these two portions is determined to be within 1.3 to 1.6, the noise due to the flowing air and the load to the fan driving motor can be significantly reduced, thus being advantageous.
Furthermore, the dimensions of the R-portions of the tip ends of both the fan blade satisfy the relation of (Rb/Ra=0.1 to 0.8), so that the noise can be also reduced and the increase in the motor input power consumption can be also suppressed.
In addition, the fan blade according to the present embodiment has the largest thickness at its central portion in the blade chord direction, i.e., blade arcuate peripheral portion, so that the noise and the motor input can be made minimal.
In order to confirm the effective functions of the present invention, the following experiments had been performed as Test Examples by incorporating the cross flow fan having the above structures and dimensions into an indoor unit ID shown in
With reference to
A cross flow fan having the structure shown in
As can be seen from the graph of
A cross flow fan having the same structure as that in the Example 1 was assembled in the indoor unit ID of the air conditioner as shown in
As can be seen from the graph of
A cross flow fan having the same structure as that in the Example 1 or 2 was assembled in the indoor unit ID of the air conditioner as shown in
As can be seen from the graph of
Further, it will easily be noted that a more preferred example of the present invention will be provided by a cross flow fan having combined characteristic features of the cross flow fans represented by the embodiments of FIGS. 3 to 5, respectively.
Number | Date | Country | Kind |
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P2004-218925 | Jul 2004 | JP | national |