Vibration reduction cross-flow fan blade and air conditioning equipment applying vibration reduction cross-flow fan blade

Abstract

The utility model relates to the technical field of air conditioning equipment, in particular to a vibration reduction cross-flow fan blade and the air conditioning equipment applying the vibration reduction cross-flow fan blade. According to the technical scheme, the vibration reduction cross-flow fan blade comprises a fan blade body, and the fan blade body comprises a rubber end wind wheel, an end disc and a plurality of middle-section wind wheels; the rubber end wind wheel, the multiple middle-section wind wheels and the end disc are in axial butt joint and are welded into a whole. A first rubber shaft sleeve assembly used for being connected with a motor shaft is arranged in the center of the rubber end wind wheel, and a second rubber shaft sleeve assembly used for being connected with a steel shaft is arranged in the center of the end disc. The first rubber shaft sleeve assembly and the second rubber shaft sleeve assembly are concentrically arranged and serve as rubber vibration reduction assemblies at the two ends of the fan blade body correspondingly. The scheme has the advantages of balanced damping effect, good long-term stability and remarkable noise control effect.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning equipment technology, and in particular to an air conditioning equipment with a vibration-damping cross-flow fan blade and its application. Background Technology

[0002] In air conditioning equipment, the cross-flow fan blade is a core air supply component, and its vibration and noise control directly affect the user experience and equipment reliability. Traditional cross-flow fan blades typically use a rigid connection to fix the blade assembly to the motor shaft. During operation, the combined effect of airflow impact and motor vibration easily generates high-frequency mechanical vibration, leading to excessive noise and accelerated bearing wear.

[0003] In existing technologies, such as the patent "A Cross-flow Fan Blade Structure" (publication number CN205714935U), a combined design including a steel shaft end plate, a rubber end plate, and multiple intermediate sections is disclosed. The steel shaft end plate consists of an injection-molded disc and a rigid steel shaft, with only the rubber end plate achieving localized vibration damping through rubber components. Although this solution introduces elastic buffering on one side, it still has significant drawbacks. First, the vibration damping capacity is uneven. The elastic modulus of the rigid steel shaft end and the rubber end plate differ significantly (the elastic modulus of the steel shaft is approximately 200 GPa, while that of the rubber is only 0.01-0.1 GPa), resulting in asymmetrical transmission of vibration energy at both ends. Actual measurements show that the vibration acceleration amplitude at the steel shaft end is 60%-70% higher than that at the rubber end, causing axial oscillation of the fan blades and generating additional aerodynamic noise. This uneven vibration damping effect not only fails to effectively suppress overall vibration but may also lead to unstable fan blade operation, affecting the overall performance of the air conditioning equipment. Second, long-term stability is insufficient. Unilateral vibration damping causes stress concentration on the rubber end plate, accelerating rubber aging. Industry test data shows that after 2000 hours of continuous operation, the compression set of the rubber end plate of this type of structure exceeds 15%, resulting in a vibration damping performance decrease of over 30%. This performance degradation not only affects the long-term performance of the air conditioning equipment but may also increase maintenance costs and frequency, reducing user satisfaction. Furthermore, noise suppression is significantly limited. Due to the lack of buffering at the steel shaft end, high-frequency vibrations from the motor are directly transmitted to the fan blade housing, generating sharp abnormal noises in the 2000-4000Hz frequency range. This high-frequency noise not only affects the user experience but may also cause the air conditioning equipment to fail to meet relevant noise standards, limiting its market application.

[0004] In summary, existing cross-flow fan structures have significant shortcomings in terms of vibration reduction, long-term stability, and noise control. These issues not only affect the performance and lifespan of air conditioning equipment but may also lead to a decline in user experience and increased maintenance costs.

[0005] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0006] In order to solve the above problems, the purpose of this utility model is to provide a vibration-damping cross-flow fan blade and its application in air conditioning equipment, which has the advantages of balanced vibration reduction effect, good long-term stability and significant noise control effect.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This application provides a vibration-damping cross-flow fan blade, the technical solution of which is as follows: It includes a fan blade body, the fan blade body comprising a rubber-end impeller, an end plate, and multiple intermediate impeller sections; the rubber-end impeller, the multiple intermediate impeller sections, and the end plate are axially connected and welded together; a first rubber bushing assembly for connecting a motor shaft is provided at the center of the rubber-end impeller, and a second rubber bushing assembly for connecting a steel shaft is provided at the center of the end plate; the first rubber bushing assembly and the second rubber bushing assembly are concentrically arranged, and both serve as rubber vibration-damping components at both ends of the fan blade body.

[0009] Furthermore, this application also proposes that the steel shaft is inserted into the shaft hole of the second rubber bushing assembly and forms a relative rotatable connection with the second rubber bushing assembly; or, the steel shaft is configured to rotate and is inserted and fixed in the shaft hole of the second rubber bushing assembly, and is circumferentially linked with the second rubber bushing assembly.

[0010] Furthermore, this application also proposes that the outer diameters of the rubber end impeller, end plate, and multiple middle section impellers are the same, forming a continuous cylindrical blade structure.

[0011] Furthermore, this application also proposes that both the first rubber bushing assembly and the second rubber bushing assembly include a bushing, an annular plate, and a rubber layer; the rubber layer is integrally injection molded between the bushing and the annular plate, with its inner side covering the surface of the bushing and its outer side covering the inner edge of the annular plate; the outer edge of the annular plate is integrally injection molded inside the rubber end impeller or end plate.

[0012] Furthermore, this application also proposes that the rubber layer material of the first rubber bushing assembly and the second rubber bushing assembly is vulcanized rubber with a hardness range of Shore A 40-70 degrees.

[0013] Furthermore, this application also proposes that the outer surface of the rubber layer is provided with a textured surface to enhance the vibration damping effect.

[0014] Furthermore, this application also proposes that a transition layer is provided between the rubber end impeller and the first rubber bushing assembly, and between the end plate and the second rubber bushing assembly, wherein the transition layer is a flexible buffer material.

[0015] Furthermore, this application also proposes an air conditioning device, including the aforementioned vibration-damping cross-flow fan blades.

[0016] As described above, the air conditioning equipment for a vibration-damping cross-flow fan blade and its application provided in this application includes a fan blade body, which includes an rubber-end impeller, an end plate, and multiple intermediate impeller sections. A first rubber bushing assembly for connecting a motor shaft is disposed at the center of the rubber-end impeller, and a second rubber bushing assembly for connecting a steel shaft is disposed at the center of the end plate. The first and second rubber bushing assemblies are concentrically arranged and serve as rubber vibration damping components at both ends of the fan blade body. By setting rubber vibration damping components at both ends of the fan blade body, bidirectional dissipation of vibration energy is achieved, solving the problems of uneven vibration damping effect, insufficient long-term stability, and limited noise suppression in the prior art. It has the advantages of balanced vibration damping effect, good long-term stability, and significant noise control effect. Attached Figure Description

[0017] Figure 1 A schematic diagram of a vibration-damping cross-flow fan blade provided in this application.

[0018] Figure 2 The present application provides schematic diagrams of the first rubber bushing assembly 21 and the second rubber bushing assembly 22. Detailed Implementation

[0019] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0020] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.

[0022] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0023] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0024] Example 1:

[0025] like Figure 1 As shown, this embodiment relates to a vibration-damping cross-flow fan blade, including a fan blade body 1. The fan blade body 1 includes a rubber-end impeller 11, an end plate 12, and multiple middle-section impellers 13. The rubber-end impeller 11, the multiple middle-section impellers 13, and the end plate 12 are axially connected and welded together. A first rubber bushing assembly 21 for connecting the motor shaft is provided at the center of the rubber-end impeller 11, and a second rubber bushing assembly 22 for connecting the steel shaft 3 is provided at the center of the end plate 12. The first rubber bushing assembly 21 and the second rubber bushing assembly 22 are concentrically arranged, and both serve as rubber vibration damping components at both ends of the fan blade body 1. The welded integration can be achieved through laser welding, ultrasonic welding, or electron beam welding processes. This technical solution constructs a bidirectional elastic support system through symmetrically arranged rubber vibration damping components at both ends. Specifically, vibration on the motor shaft side is isolated by the first rubber bushing assembly 21, and vibration on the steel shaft 3 side is synchronously absorbed by the second rubber bushing assembly 22. The matching of the vibration damping moduli at both ends reduces the axial vibration amplitude by more than 40%. The welded-in-one blade structure maintains the necessary rigidity while ensuring uniform dissipation of vibration energy through the rubber layers 213 at both ends. Compared to existing single-sided vibration damping structures, this design reduces the difference in vibration acceleration between the two ends of the blade from 60-70% to less than 15%, extends the lifespan of rubber components by more than 2 times, and reduces operating noise by 5-8 dB(A). The concentrically arranged rubber components ensure symmetrical transmission of vibration energy along the axial direction, effectively suppressing aerodynamic noise caused by blade oscillation.

[0026] In a specific implementation, the steel shaft 3 is inserted into the shaft hole of the second rubber bushing assembly 22, forming a relative rotational connection with the second rubber bushing assembly 22; or, the steel shaft 3 is configured to rotate, and its insertion and fixing within the shaft hole of the second rubber bushing assembly 22, circumferentially linked with the second rubber bushing assembly 22. Specifically, the relative rotational connection can be achieved by: providing a low-friction coefficient coating (such as polytetrafluoroethylene) on the outer surface of the steel shaft 3, or using a clearance fit to maintain a radial clearance of 0.05-0.1mm between the steel shaft 3 and the inner wall of the shaft hole. Circumferential linkage can be achieved by: providing a keyway and flat key structure between the steel shaft 3 and the shaft hole, or using an interference fit to make the outer diameter of the steel shaft 3 0.02-0.05mm larger than the inner diameter of the shaft hole, or using a screw fastening method. Thus, this technical solution optimizes for different vibration transmission characteristics through two optional connection configurations. When a relative rotational connection is used, the axial degree of freedom between the steel shaft 3 and the rubber bushing 211 allows axial vibration to be absorbed through the shear deformation of the rubber layer 213, while maintaining radial positioning accuracy within ±0.1mm. When circumferential linkage is used, the viscoelastic properties of the rubber layer 213 can effectively attenuate the torsional vibration transmitted by the motor. Actual measurements show that it can reduce the torsional vibration amplitude by more than 40% under 1000-3000rpm conditions. Compared with the traditional single rigid connection method, this design allows the fan blade to select an appropriate connection mode according to the motor type (such as induction motors which are prone to torsional vibration, and brushless DC motors which are prone to axial vibration), achieving targeted optimization of vibration reduction performance without increasing structural complexity.

[0027] Furthermore, this application proposes that the outer diameters of the rubber-end impeller 11, end plate 12, and multiple middle-section impellers 13 are identical, forming a continuous cylindrical blade structure. The identical outer diameters of the rubber-end impeller 11, end plate 12, and middle-section impellers 13 can be achieved by using a unified mold for injection molding of each component, ensuring that the outer diameter tolerance is controlled within ±0.5mm. The specific value of the identical outer diameter can be set to standard dimensions such as 80mm, 100mm, or 120mm according to the blade design requirements. The axial length of the continuous cylindrical structure can be configured to 200-500mm, and the number of middle-section impellers 13 is set at 50mm intervals. This technical solution constructs a cylindrical airflow channel without step changes by unifying the radial dimensions of each component of the blade body 1. Specifically, the consistency of the outer diameter ensures that the boundary layer remains continuous when the airflow flows axially, avoiding airflow separation and vortices caused by abrupt changes in cross-section.

[0028] like Figure 2As shown, both the first rubber bushing assembly 21 and the second rubber bushing assembly 22 include a bushing 211, an annular plate 212, and a rubber layer 213. The rubber layer 213 is integrally injection molded between the bushing 211 and the annular plate 212, with its inner side covering the surface of the bushing 211 and its outer side covering the inner edge of the annular plate 212. The outer edge of the annular plate 212 is integrally injection molded into the interior of the rubber end impeller 11 or end plate 12. The bushing 211 can be made of metal or engineering plastic, wherein the metal bushing 211 is preferably stainless steel or aluminum alloy, and the engineering plastic bushing 211 is preferably polyetheretherketone or polyimide. The thickness of the annular plate 212 can be set to 1-3 mm, and its material can be selected to be the same plastic as the impeller body 1 to enhance the bonding strength. In a preferred embodiment, the contact surfaces of the rubber layer 213 with the bushing 211 and the annular plate 212 can be provided with dovetail groove structures, for example, by machining axial grooves on the outer surface of the bushing 211, so that the rubber layer 213 forms a corresponding protruding structure. This technical solution solves the contradiction between connection strength and vibration reduction stability through the synergistic effect of a triple structure. The bushing 211 provides a rigid support base to ensure a reliable connection with the motor shaft or steel shaft 3; the annular plate 212 serves as a transition carrier, and its outer edge is connected to the fan blade body 1 through molecular chain entanglement to achieve stress-free connection; the rubber layer 213 simultaneously covers the bushing 211 and the annular plate 212, forming a continuous elastic medium layer. Thus, vibration energy is forced through the shear deformation path of the rubber layer 213 during transmission, where axial vibration is dissipated through the covering interface between the rubber layer 213 and the bushing 211, and radial vibration is absorbed through the joint surface between the rubber layer 213 and the annular plate 212. Compared with existing single-sided vibration reduction structures, this design enables vibration energy to decay synchronously at both ends. Actual measurements show that the axial vibration transmission rate is reduced by 42%, and the compression permanent deformation rate of the rubber component is controlled within 8% after 3000 hours of durability testing.

[0029] Furthermore, this application proposes that the rubber layer 213 of the first rubber bushing assembly 21 and the second rubber bushing assembly 22 is made of vulcanized rubber with a hardness range of Shore A 40-70. The vulcanized rubber material of the rubber layer 213 provides stable elastic recovery performance due to its cross-linked molecular structure, ensuring effective dissipation of vibration energy. The hardness is limited to Shore A 40-70, a range that ensures sufficient rigidity to maintain the stability of the fan blades (below 40 degrees can easily lead to eccentric swaying of the fan blades) while maintaining appropriate flexibility to achieve vibration absorption (above 70 degrees, the vibration reduction effect is sharply reduced). Using the same hardness standard for both bushing assemblies avoids asymmetrical vibration transmission caused by material differences. Specifically, the coating thickness of the rubber layer 213 can be adjusted within the range of 2-5 mm. Specifically, when using soft rubber with a Shore A 40-50 degree, the coating thickness is preferably 4-5 mm; when using hard rubber with a Shore A 60-70 degree, the coating thickness can be reduced to 2-3 mm. Vulcanized rubber can be prepared by reacting natural or synthetic rubber with a vulcanizing agent under heating conditions to form a cross-linked network structure. As a preferred embodiment, sulfur vulcanization can be used, with sulfur accounting for 1.5-3% of the rubber weight, and sulfenamides such as CZ or NS used as accelerators at 0.5-1.5%. Hardness can be adjusted by changing the amount of carbon black filler; for example, controlling the N330 carbon black filler to the range of 30-50 phr can achieve the target hardness value. Furthermore, antioxidants such as 4010NA or RD can be added to the rubber layer 213 to improve its resistance to heat and oxygen aging, and paraffin wax can be added as a physical antioxidant to delay ozone aging.

[0030] Furthermore, the outer surface of the rubber layer 213 is provided with a textured surface to enhance the vibration damping effect. The textured structure allows the rubber layer 213 to form multiple points of contact with adjacent components, increasing the contact area by 20%-40% compared to a planar structure, thereby improving the damping effect by increasing the friction interface. Secondly, the micro-deformation generated by the texture can effectively dissipate mid-to-high frequency vibration energy. In addition, the elastic cavity formed by the texture can buffer impact loads and prevent stress concentration in the rubber layer 213.

[0031] Furthermore, transition layers 4 are provided between the rubber end impeller 11 and the first rubber bushing assembly 21, and between the end plate 12 and the second rubber bushing assembly 22. The transition layers 4 are flexible cushioning materials. The transition layers 4 can be made of polyurethane foam, silicone sponge, or rubber composite materials, and the thickness is preferably 1-3 mm. The density range of the polyurethane foam is recommended to be 80-150 kg / m³. 3The compression modulus is controlled between 0.5-2 MPa; the Shore hardness of the silicone sponge should be selected as A10-30 degrees; the rubber composite material can be a composite structure of nitrile rubber and metal mesh, with a metal mesh count of 40-60 mesh. The transition layer 4 is fixed between the metal component and the rubber assembly by bonding or molding. Epoxy resin-based structural adhesives are preferred, with a shear strength of not less than 5 MPa after curing. The surface of the transition layer 4 can be provided with a wavy or sawtooth interface structure to increase the contact area and optimize stress distribution. This technical solution forms a structure with a stiffness gradient by setting a transition layer 4 between the metal component and the rubber assembly. Specifically, the elastic modulus of the transition layer 4 is between that of the metal and the rubber, causing the material stiffness along the vibration transmission path to decrease in a stepwise manner, thereby effectively reducing interface stress concentration. Measured data shows that the transition layer 4 can improve the vibration transmission loss in the 2000Hz frequency band by more than 8 dB, while reducing the peak interface stress by approximately 35%. Compared to traditional direct connection methods, this structure can simultaneously attenuate the vibration energy at both ends of the blade, avoiding the axial moment imbalance problem caused by unilateral vibration reduction. The damping characteristics of the flexible buffer material can absorb high-frequency vibration energy, reduce the amplitude of vibration transmission to the blade body 1, and thus significantly improve the vibration aggravation phenomenon caused by rigid transition.

[0032] Example 2:

[0033] This embodiment also proposes an air conditioning device, including the vibration-damping cross-flow fan blade described in Embodiment 1. The vibration-damping cross-flow fan blade includes a fan blade body 1, which includes a rubber-end impeller 11, an end plate 12, and multiple intermediate impellers 13. The rubber-end impeller 11, the multiple intermediate impellers 13, and the end plate 12 are axially connected and welded together. A first rubber bushing assembly 21 for connecting the motor shaft is provided at the center of the rubber-end impeller 11, and a second rubber bushing assembly 22 for connecting the steel shaft 3 is provided at the center of the end plate 12. The first rubber bushing assembly 21 and the second rubber bushing assembly 22 are concentrically arranged, and both serve as rubber vibration damping components at both ends of the fan blade body 1. This air conditioning device achieves symmetrical dissipation of vibration energy by integrating a cross-flow fan blade with a bidirectional rubber vibration damping structure and utilizing the first rubber bushing assembly 21 and the second rubber bushing assembly 22 at both ends of the fan blade. The main body of the fan blade 1 forms an elastic support system through the bidirectional rubber bushing assembly of the rubber-end impeller 11 and the end plate 12, allowing motor vibration to be uniformly attenuated after being buffered by the rubber layer 213. The rubber assemblies at both ends adopt the same vibration damping structure, eliminating the vibration transmission imbalance caused by rigid connections. The hardness and texture design of the rubber layer 213 optimizes the vibration absorption frequency band. These features work synergistically to significantly reduce vibration noise in the 2000-4000Hz frequency band while maintaining the fan blade rigidity, and extend the service life of the rubber assemblies.

[0034] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0035] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1.A damping through-flow fan blade, comprising a fan blade body (1), characterized in that: the fan blade body (1) comprises an end rubber wheel (11), an end disc (12) and a plurality of middle section wheels (13); the end rubber wheel (11), the plurality of middle section wheels (13) and the end disc (12) are axially butted and integrally welded; a first rubber shaft sleeve assembly (21) for connecting a motor shaft is arranged at the center of the end rubber wheel (11), and a second rubber shaft sleeve assembly (22) for connecting a steel shaft is arranged at the center of the end disc (12); the first rubber shaft sleeve assembly (21) and the second rubber shaft sleeve assembly (22) are concentrically arranged, and each of them is a rubber damping assembly at the two ends of the fan blade body (1). 2.The damping through-flow fan blade according to claim 1, characterized in that: the steel shaft (3) is inserted into the shaft hole of the second rubber shaft sleeve assembly (22) and is in relative rotation connection with the second rubber shaft sleeve assembly (22); or, the steel shaft (3) is arranged to rotate and is inserted and fixed in the shaft hole of the second rubber shaft sleeve assembly (22) and is in circumferential linkage with the second rubber shaft sleeve assembly (22). 3.The damping through-flow fan blade according to claim 1, characterized in that: the outer diameters of the end rubber wheel (11), the end disc (12) and the plurality of middle section wheels (13) are the same, forming a continuous cylindrical fan blade structure. 4.The damping through-flow fan blade according to claim 1, characterized in that: each of the first rubber shaft sleeve assembly (21) and the second rubber shaft sleeve assembly (22) comprises a shaft sleeve (211), an annular sheet (212) and a rubber layer (213); the rubber layer (213) is integrally injection molded between the shaft sleeve (211) and the annular sheet (212), and is wrapped on the surface of the shaft sleeve (211) on the inner side and wrapped on the inner edge of the annular sheet (212) on the outer side; the outer edge of the annular sheet (212) is integrally injection molded in the inner part of the end rubber wheel (11) or the end disc (12). 5.The damping through-flow fan blade according to any one of claims 1-4, characterized in that: the material of the rubber layer (213) of the first rubber shaft sleeve assembly (21) and the second rubber shaft sleeve assembly (22) is vulcanized rubber, and the hardness range is Shore A 40-70 degrees. 6.The damping through-flow fan blade according to claim 4, characterized in that: the outer surface of the rubber layer (213) is provided with concave-convex lines for enhancing the damping effect. 7.The damping through-flow fan blade according to claim 1, characterized in that: a transition layer (4) is arranged between the end rubber wheel (11) and the first rubber shaft sleeve assembly (21) and between the end disc (12) and the second rubber shaft sleeve assembly (22), and the transition layer (4) is a flexible cushioning material. The damping through-flow fan blade according to any one of claims 1-7. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 8. An air conditioning apparatus characterized by comprising: ​

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