Counter-rotating fan and air conditioner

Abstract

The application relates to a counter-rotating fan, which comprises a hub and a first blade, and further comprises a cap which is conical and arranged at the windward end surface of the hub to guide airflow to the first blade. The airflow is guided through the cap, the uniformity of the airflow at the inlet of the counter-rotating fan is ensured, the anti-separation ability and the aerodynamic noise of the airflow in the counter-rotating fan are reduced, the flow and the pressure of the counter-rotating fan are improved, and the overall performance of the counter-rotating fan is improved. The application further discloses an air conditioner.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fan, for example, to a contra-rotating fan and an air conditioner. BACKGROUND

[0002] The contra-rotating fan generally refers to two-stage fans arranged along the same axial direction, and a driving device is arranged to drive the fans to rotate. The contra-rotating fan can provide pressure equivalent to two-stage fans. The two-stage fans can rotate at the same / different rotating speeds / rotating directions, so as to realize multiple air supply modes such as forward, reverse, long-distance, and non-sensing, and improve the flexibility of air supply. When the two-stage fans rotate in opposite directions, long-distance air supply can be realized; when the two-stage fans rotate in the same direction, air flow dispersion and non-sensing air supply can be realized. The contra-rotating fan is mainly applied in the field of engines in the prior art, and in recent years, it has been gradually applied in household appliances such as air conditioners, dehumidifiers, and electric fans.

[0003] In the process of implementing the embodiments of the present disclosure, it is found that at least the following problems exist in the related art: When the contra-rotating fan rotates, the air flow entering is disordered and uneven, and the aerodynamic noise generated is relatively large, which affects the comfort of users when the contra-rotating fan is applied to household appliances such as air conditioners. SUMMARY

[0004] To provide a basic understanding of some aspects of the disclosed embodiments, the following summary is given. The summary is not an extensive overview of the application, nor is it intended to identify key / critical elements of the application or to delineate the scope of the embodiments. The sole purpose of the summary is to present some concepts of the embodiments in a simplified form as a prelude to the more detailed description that is presented later.

[0005] The embodiments of the present disclosure provide a contra-rotating fan and an air conditioner to solve the technical problem that the air flow entering is disordered and uneven when the contra-rotating fan rotates, and the aerodynamic noise generated is relatively large.

[0006] In some embodiments, the contra-rotating fan includes a hub and a first blade, and further includes: a cap, which is conical and arranged at a windward end surface of the hub to guide the air flow to the first blade.

[0007] The embodiments of the present disclosure further provide an air conditioner including the contra-rotating fan according to any one of the preceding embodiments.

[0008] The contra-rotating fan and the air conditioner provided by the embodiments of the present disclosure can achieve the following technical effects: The air flow is guided by the cap to ensure the uniformity of the air flow entering the contra-rotating fan, reduce the anti-separation ability and aerodynamic noise of the air flow in the contra-rotating fan, and further improve the flow rate and pressure of the contra-rotating fan, and improve the overall performance of the contra-rotating fan.

[0009] The foregoing general description and the following description are only exemplary and explanatory, and are not intended to limit the present application. BRIEF DESCRIPTION OF DRAWINGS

[0010] One or more embodiments are illustrated by way of example in the figures that are not intended to be limiting of the embodiments. Like numbers refer to like elements throughout the drawings, which are not necessarily to scale, and in which:

[0011] Figure 1 is a cross-sectional view of a counter-rotating fan provided by an embodiment of the present disclosure;

[0012] Figure 2 is a cross-sectional view of a counter-rotating fan provided by an embodiment of the present disclosure; Figure 1 is a cross-sectional view of a counter-rotating fan provided by an embodiment of the present disclosure;

[0013] Figure 3 is another structural view of a machine casing provided by an embodiment of the present disclosure;

[0014] Figure 4 is a structural view of a counter-rotating fan provided by an embodiment of the present disclosure;

[0015] Figure 5 is another structural view of a counter-rotating fan provided by an embodiment of the present disclosure;

[0016] Figure 6 is a structural view of a first flow guide of a counter-rotating fan provided by an embodiment of the present disclosure;

[0017] Figure 7 is another structural view of a counter-rotating fan provided by an embodiment of the present disclosure;

[0018] Figure 8 is another structural view of a counter-rotating fan provided by an embodiment of the present disclosure;

[0019] Figure 9 is another structural view of a counter-rotating fan provided by an embodiment of the present disclosure.

[0020] Reference Signs:

[0021] 10, machine casing; 101, groove; 20, hub; 30, first blade; 40, second blade; 50, inner cylinder; 501, first flow guide; 60, cap; 70, flow guide blade. DETAILED DESCRIPTION

[0022] In order to enable a more detailed understanding of the features and technical content of the embodiments of the present disclosure, the implementation of the embodiments of the present disclosure is described in detail below with reference to the accompanying drawings, which are only used for reference and do not limit the embodiments of the present disclosure. In the following technical description, in order to facilitate explanation, a plurality of details are provided to provide a full understanding of the disclosed embodiments. However, one or more embodiments can still be implemented without these details. In other cases, well-known structures and devices can be simplified to facilitate the drawings.

[0023] As Figure 1 and Figure 2 shown, the disclosure provides a kind of counter-rotating fan, comprising hub 20, it is provided with first blade 30, further comprising: casing 10, cover is located in the outside of first blade 30, and the inner wall is provided with recess 101 corresponding to the position of the blade top of first blade 30.Therein, the blade top of first blade 30 is the edge or top edge of radial direction when first blade 30 rotates, the outside of first blade 30 is the space outside the coverage area of first blade 30 rotation.Noise formation is related to the compression degree of air in the gap between blade top and casing, when first blade 30 rotates, the vortex speed of airflow in the gap between blade top and casing is too high, thereby generating relatively sharp noise.The recess 101 of the inner wall of casing 10 corresponds the blade top position of first blade 30, when first blade 30 rotates, due to the existence of recess, the vortex speed of airflow in the gap between blade top and casing is reduced to a certain extent when passing through recess, in addition, the setting of recess helps to alleviate the blockage problem of the gap between blade top and casing, increases the flow area of airflow in the gap, so as to reduce the noise when counter-rotating fan operates.

[0024] Wherein, when vortex airflow passes through recess 101, airflow flows in and out in recess 101, when airflow flows into recess 101, vortex airflow impacts the inner wall of recess 101, the inner wall of recess 101 absorbs part of the impact force brought by airflow, thereby reducing the flow rate of vortex airflow, and further reducing the noise generated by airflow;Airflow flows out under the guidance of the inner wall of recess 101, at this time, the uniformity of the outflowing airflow is significantly improved compared with the inflowing airflow, after vortex airflow continuously flows through multiple recesses 101, the impact force carried by airflow due to vortex is buffered and absorbed by recess 101.

[0025] In some embodiments, recess 101 is distributed along the inner circumference of casing 10.When vortex is generated by airflow passing through blade top, vortex airflow can directly flow into the recess 101 of the inner wall of casing 10, and the impact force brought by airflow is absorbed and buffered by recess 101, thereby reducing the aerodynamic noise generated by airflow directly impacting the inner wall of casing 10.

[0026] In some embodiments, recess 101 is in continuous annular structure along the inner circumference of casing 10.Continuous annular recess 101 is convenient for processing, secondly, the airflow in annular recess 101 can maintain a certain uniformity when it is buffered, which is beneficial to improve the stability of casing 10.

[0027] In some embodiments, recess 101 is in non-continuous annular structure along the inner circumference of casing 10.I.e., multiple recesses 101 are arranged in a spaced manner to form annular structure, which helps to improve the mechanical strength of casing 10 when recess 101 buffers the impact force of airflow.

[0028] The grooves 101 can be parallel to the radial direction of the inner circumference of the casing 10, or can form a certain angle with the radial direction of the inner circumference of the casing 10. The flow direction of the vortex is wide, and the vortex flows in multiple directions. The grooves 101 are arranged in multiple directions on the inner wall of the casing 10, which helps to buffer the vortex flow to the maximum extent and reduce the aerodynamic noise.

[0029] In some embodiments, the grooves 101 are arranged in multiple rows and are spaced apart along the length direction of the casing 10, as shown in FIG. 2. Figure 2 The multiple rows of grooves 101 are uniformly distributed on the inner circumferential surface of the casing 10, and the length direction of the casing 10, i.e., the axial direction of the hub 20, is arranged along the axial direction of the hub 20. In this way, when the airflow passes between the casing 10 and the blade tip, the airflow sequentially passes through the multiple rows of grooves 101, and the vortex in the airflow continuously flows in and out of the grooves 101. After being buffered by the multiple rows of grooves 101, the vortex of the airflow is diluted, and the vibration caused by the vortex is reduced, thereby reducing the aerodynamic noise.

[0030] In some embodiments, the greater the distance D between the blade tip and the inner wall of the casing 10, the greater the spacing L of the grooves 101. When the distance D between the blade tip and the inner wall of the casing 10 is greater, the spacing of the grooves 101 is increased, which on the one hand absorbs and buffers the airflow, and on the other hand reduces the number of grooves to ensure the mechanical strength of the casing 10.

[0031] In some embodiments, the spacing of the grooves 101 satisfies the following relationship: D≤L≤2D, where L represents the spacing between the grooves 101, and D represents the distance between the blade tip and the inner wall of the casing 10. By requiring D≤L≤2D, it is ensured that the airflow of the first blade 30 passes through the grooves 101 for buffering, and the purpose of absorbing and buffering the airflow by the grooves 101 is achieved to the maximum extent. In the case of ensuring the mechanical strength of the casing 10, the vortex generated between the first blade 30 and the inner wall of the casing 10 is absorbed by the grooves 101, effectively reducing the aerodynamic noise when the first blade 30 rotates. If the spacing L of the grooves 101 is greater than 2D, i.e., the spacing distance between adjacent grooves 101 is relatively large, the vortex airflow flowing through the gap between the blade tip and the inner wall of the casing 10 does not pass through the grooves 101 for buffering, but directly acts on the inner wall of the casing 10, thereby causing the defect of aerodynamic noise. If the spacing L of the grooves 101 is less than D, although the vortex airflow is sufficiently buffered by the grooves 101, a large number of grooves 101 are arranged in the same distance on the inner wall of the casing 10, which is not conducive to maintaining the mechanical strength of the casing 10, and further affects the overall performance of the vortex fan.

[0032] In some embodiments, the cross section of the groove 101 is semicircular. The semicircular structure of the groove 101 receives the vortex airflow generated by the rotation of the first blade 30 with the largest opening area, and the depth of the semicircular structure meets the purpose of the groove 101 absorbing and buffering the vortex airflow. The semicircular structure of the groove 101 is convenient for processing, and secondly, it helps to ensure the mechanical strength of the casing 10.

[0033] In some embodiments, the cross section of the groove 101 can also be square, triangular or arcuate. These shapes of the groove 101 can also absorb the vortex to a certain extent and reduce the aerodynamic noise of the cyclone fan. Among them, when the cross section of the groove 101 is square, the square groove can be inclinedly arranged, and the side wall of the groove forms a certain angle with the inner side wall of the casing. In this way, it is helpful for the smooth entry and exit of the airflow. Figure 3

[0034] In some embodiments, the larger the distance D between the blade tip and the inner wall of the casing 10, the larger the radius of the groove 101. The larger the distance between the blade tip and the inner wall of the casing 10, the larger the airflow passing through, and the larger the radius of the groove 101, which helps the groove 101 to complete the absorption and buffering work of the vortex.

[0035] In some embodiments, the radius of the groove 101 satisfies the following relationship: 3D≤R≤5D, wherein R represents the radius of the groove 101, and D represents the distance between the blade tip and the inner wall of the casing 10. Through the requirement of 3D≤R≤5D, it is ensured that the groove 101 can complete the absorption and buffering work of the airflow when the distance between the blade tip and the inner wall of the casing 10 increases and the airflow passing through increases.

[0036] In some embodiments, the distance between the grooves 101 farthest apart is less than the width of the blade. The airflow passing through the groove 101 is reduced through the absorption and buffering of the groove 101, and the width of the blade through which the airflow passes is greater than the distance between the grooves 101 farthest apart. The setting makes part of the airflow generated by the first blade 30 and the airflow buffered by the groove 101 merge and exit, solving the problem of insufficient air supply distance caused by the decrease of the airflow. The first blade 30 generates part of the airflow, i.e. the airflow that does not pass through the groove 101 for buffering.

[0037] In some embodiments, as shown in Figure 4 and Figure 5 The cyclone fan further comprises: a second blade 40 arranged on the hub 20 and on one side of the first blade 30, and the length of the blade is shorter than the length of the first blade 30; and an inner cylinder 50 arranged between the casing 10 and the hub 20 and covering the outside of the second blade 40.

[0038] ​The first blade 30 and the second blade 40 are arranged in sequence along the axial direction of the hub 20, and the lengths of the first blade 30 and the second blade 40 are different. The inner cylinder 50 is arranged outside the second blade 40. When the airflow passes through the first blade 30, the airflow passes through the flow channel formed by the casing 10. When the airflow passes through the second blade 40, the airflow is divided by the inner cylinder 50, and part of the airflow passes through the inside of the inner cylinder 50, and the other part of the airflow passes through the flow channel between the inner cylinder 50 and the casing 10. The airflow sent out from the inner cylinder 50 has a long blowing distance, and the airflow sent out from between the casing 10 and the inner cylinder 50 has a short blowing distance, so that the contra-rotating fan can have both long-distance blowing and short-distance blowing.

[0039] In some embodiments, the air outlet side of the casing 10 includes a contraction section, and the contraction angle of the contraction section is α, and 0°≤α≤30°. The contraction section on the air outlet side of the casing 10 helps to converge the airflow, improves the air gathering capacity of the air outlet, and improves the quality of the air outlet. By using different contraction angles, different blowing distances of the contra-rotating fan can be achieved to meet various needs. In addition, by using different angles of the contraction section on the air outlet side of the casing 10, different angle blowing requirements can also be achieved.

[0040] The disclosure also provides another structure of the contra-rotating fan.

[0041] The contra-rotating fan includes the casing 10 and the hub 20 arranged inside the casing 10. The first blade 30 and the second blade 40 are arranged in sequence along the axial direction of the hub 20, and the blade length of the second blade 40 is shorter than the blade length of the first blade 30. Figure 4 As shown in the figure.

[0042] For the embodiments of the first blade 30 and the second blade 40, please refer to the above description, which will not be repeated here.

[0043] In some embodiments, the contra-rotating fan further includes an inner cylinder 50 arranged inside the casing 10 and covering the outside of the second blade 40. Figure 5 As shown in the figure.

[0044] The inner cylinder 50 is coaxially arranged with the casing 10.

[0045] The diameter of the inner cylinder 50 is greater than the diameter of the area surrounded by the rotation of the second blade 40 and smaller than the diameter of the area surrounded by the rotation of the first blade 30.

[0046] For the embodiments of the inner cylinder 50, please refer to the above description, which will not be repeated here.

[0047] In some embodiments, the inner wall of the inner cylinder 50 is provided with a groove (not shown in the figure) corresponding to the position of the tip of the second blade 40. The tip of the second blade 40 is the edge or top edge in the radial direction when the second blade 40 rotates. By providing a groove on the inner wall of the inner cylinder 50 corresponding to the position of the tip of the second blade 40, when the second blade 40 rotates, the vortex generated by the airflow passing through the tip of the second blade 40 is absorbed and buffered by the groove, thereby reducing the aerodynamic noise generated during the operation of the cyclone fan.

[0048] When the vortex airflow passes through the groove, the airflow flows in and out of the groove, and when the airflow flows into the groove, the vortex airflow impacts the inner wall of the groove, and the inner wall of the groove absorbs part of the impact force brought by the airflow, thereby reducing the noise caused by the vibration of the vortex airflow directly acting on the inner wall of the inner cylinder 50. The outflow of the airflow is guided by the inner wall of the groove, and the uniformity of the outflow is significantly improved compared to the inflow. After the vortex airflow continuously flows through multiple grooves, the impact force carried by the vortex airflow is buffered and absorbed by the grooves, eliminating the aerodynamic noise generated during the operation of the cyclone fan.

[0049] In some embodiments, the grooves are distributed along the inner circumference of the inner cylinder 50. When the vortex airflow generated by the tip of the second blade 40 directly flows into the groove on the inner wall of the inner cylinder 50, the impact force brought by the airflow is absorbed and buffered by the groove, reducing the aerodynamic noise caused by the direct impact of the airflow on the inner wall of the inner cylinder 50.

[0050] In some embodiments, the grooves are arranged in multiple rows and spaced along the length direction of the inner cylinder 50. The multiple rows of grooves are uniformly distributed on the inner circumferential surface of the inner cylinder 50, and the length direction of the inner cylinder 50, i.e. the axial direction of the hub 20, the multiple rows of grooves are arranged in the axial direction of the hub 20. In this way, when the airflow passes between the inner cylinder 50 and the tip of the second blade 40, the airflow successively passes through the multiple rows of grooves, and the vortex in the airflow continuously flows into and out of the grooves. After being buffered by the multiple rows of grooves, the vortex of the airflow is diluted and the vibration caused by the vortex is reduced, thereby reducing the aerodynamic noise generated.

[0051] In some embodiments, the size between the casing 10, the inner cylinder 50 and the hub 20 satisfies the following relationship: k = (D1 2 -D2 2 ) / (d1 2 -d2 2 ), where D1 is the inner diameter of the casing 10, D2 is the outer diameter of the inner cylinder 50, d1 is the inner diameter of the inner cylinder 50, d2 is the outer diameter of the hub 20, and 0.5 ≤ k ≤ 1.

[0052] The size relationship among the casing 10, the inner cylinder 50 and the hub 20 helps to ensure a certain air supply; secondly, in the air supply process, the overall pressure is appropriate, the aerodynamic noise of the contra-rotating fan in the working process is reduced, and the mechanical strength of the contra-rotating fan is ensured. If k < 0.5, the air supply is reduced; if k > 1, the air supply is increased, but the overall pressure is increased, which is not conducive to the stability of the contra-rotating fan.

[0053] In some embodiments, as shown in Figure 5 and Figure 6 The windward side of the outer wall of the inner cylinder 50 is provided with a first flow guide part 501, and the first flow guide part 501 is arc-shaped.

[0054] When the airflow on the windward side acts vertically on the outer wall of the inner cylinder 50, backflow will occur, which will cause airflow turbulence and flow separation, and adversely affect the performance of the contra-rotating fan; by providing the first flow guide part 501 on the windward side of the outer wall of the inner cylinder 50, and the arc-shaped structure of the first flow guide part 501, it helps to avoid the airflow on the windward side acting vertically on the outer wall of the inner cylinder 50, and the arc-shaped first flow guide part 501 guides the airflow to smoothly transition.

[0055] In some embodiments, the greater the height h1 of the first flow guide part 501, the greater the width b1.

[0056] The greater the height of the first flow guide part 501, the greater the width, which ensures a certain guide angle and helps the airflow to transition more smoothly and smoothly, and avoids backflow as much as possible.

[0057] In some embodiments, the height and width of the first flow guide part 501 satisfy the following relationship: 1 / 3 ≤ h1 / b1 ≤ 1 / 2, wherein h1 is the height of the first flow guide part 501, and b1 is the width of the first flow guide part 501.

[0058] When 1 / 3 ≤ h1 / b1 ≤ 1 / 2, the first flow guide part 501 can guide the airflow to smoothly transition to the maximum extent, avoiding backflow problems.

[0059] Optionally, the height h1 of the first flow guide part 501 is in the range of 8mm to 12mm.

[0060] When the height h1 of the first flow guide part 501 is in the range of 8mm to 12mm, on the one hand, the stability of the inner cylinder 50 is ensured, and on the other hand, the guiding effect of the airflow is ensured.

[0061] In some embodiments, the inner wall of the air outlet of the casing 10 is provided with a second flow guide part (not shown in the figure), and the second flow guide part is arc-shaped.

[0062] The second flow guide part arranged on the inner wall of the air outlet of the casing 10 helps to guide the flow direction of the air outflow, expand the radiation range of the air flow, improve the quality of the air outflow, and improve the comfort of the air supply. The arc-shaped structure of the second flow guide part helps to smoothly transition the air flow and avoid aerodynamic noise.

[0063] In some embodiments, the greater the height h2 of the second flow guide part, the greater the width b2.

[0064] The greater the height of the second flow guide part, the greater the width, which ensures a certain guide angle and helps to smoothly transition the air flow, thereby improving the quality of the air outflow.

[0065] In some embodiments, the height and width of the second flow guide part satisfy the following relationship: 1 / 3≤h2 / b2≤1 / 2, where h2 is the height of the second flow guide part and b2 is the width of the second flow guide part.

[0066] When 1 / 3≤h2 / b2≤1 / 2, the second flow guide part can maximize the smooth transition of the air flow, expand the radiation range of the air flow, and reduce the impact force of the air flow.

[0067] In some embodiments, the first blade 30 is closer to the air inlet of the casing 10 than the second blade 40.

[0068] The blade length of the first blade 30 is greater than the blade length of the second blade 40. A larger air flow is generated by the first blade 30 and transmitted to the second blade 40. The second blade 40 further utilizes the air flow generated by the first blade 30 to achieve the purpose of a two-stage fan. If the second blade 40 is closer to the air inlet of the casing 10, there will be air flow turbulence between the air flow generated by the rotation of the first blade 30 and the air flow generated by the rotation of the second blade 40, or the air flow generated by the rotation of the first blade 30 directly covers the air flow generated by the rotation of the second blade 40, causing waste of the second blade 40, and thus failing to achieve the purpose of a contra-rotating fan.

[0069] The present disclosure simultaneously provides another structure of a contra-rotating fan.

[0070] As shown in Figure 7 and Figure 8 The contra-rotating fan includes a hub 20 and a first blade 30, and further includes a cap 60 arranged on the windward end face of the hub 20 in a conical shape to guide the air flow to the first blade 30.

[0071] The cap 60 guides the air flow at the inlet of the contra-rotating fan, ensures the uniformity of the air flow at the inlet of the contra-rotating fan, reduces the anti-separation ability of the air flow in the contra-rotating fan, thereby improving the flow rate and pressure of the contra-rotating fan, and improving the overall performance of the contra-rotating fan.

[0072] The cap 60 is coaxially arranged with the hub 20.

[0073] In some embodiments, the cap 60 is arc-shaped and arranged at the windward end face of the hub 20 to guide the airflow to the first blade 30. The arc-shaped outer surface of the cap 60 improves the uniformity of the airflow entering the counter-rotating fan, so that the airflow is more stable when entering the counter-rotating fan, reducing the abnormal sound.

[0074] In some embodiments, as shown in FIG. 1, the windward end face is provided with a guide vane 70, and the rotation direction of the guide vane 70 is the same as that of the first blade 30. Figure 9

[0075] By arranging the guide vane 70, the uniformity of the airflow entering the counter-rotating fan is further improved; the rotation direction of the guide vane 70 is the same as that of the first blade 30, avoiding the phenomenon of airflow turbulence, while ensuring that the airflow flow is not wasted.

[0076] The guide vane 70 is arranged on the conical surface of the cap 60, wherein the vertical distance from the top of the cap 60 to the closest point of the guide vane 70 is greater than 0.3 times the height of the cap 60, and the vertical distance from the top of the cap 60 to the farthest point of the guide vane 70 is less than 0.8 times the height of the cap 60. By setting the distance between the guide vane 70 and the top of the cap 60, on the one hand, it is beneficial to maintain the stability of the counter-rotating fan when the airflow enters the counter-rotating fan, and on the other hand, it helps to improve the uniformity of the airflow.

[0077] In some embodiments, the windward end face is provided with two groups of guide vanes 70, the rotation directions of the two groups of guide vanes 70 are the same, and the diameters of the regions surrounded by the two groups of guide vanes 70 are different, wherein the group of guide vanes 70 with the smaller diameter is closer to the air inlet side of the cap 60. By the two groups of guide vanes 70, the impact force of the airflow when entering the counter-rotating fan is further reduced, and the overall performance of the counter-rotating fan is improved.

[0078] In some embodiments, the trailing edge of the guide vane 70 corresponds to the leading edge of the first blade 30.

[0079] The trailing edge of the guide vane 70 is the air outlet end face of the guide vane 70, and the leading edge of the first blade 30 is the windward end face of the first blade 30.

[0080] The trailing edge of the guide vane 70 corresponds to the leading edge of the first blade 30, so that the airflow directly transitions from the guide vane 70 to the first blade 30, reducing the loss of airflow, avoiding the vibration phenomenon of the airflow between the guide vane 70 and the first blade 30, and reducing the noise.

[0081] ​In some embodiments, the trailing edge of the guide vane 70 can also correspond to the front half of the windward side of the first blade 30. In this way, the air flow is directly introduced into the windward side of the first blade 30 under the guidance of the trailing edge of the guide vane 70, omitting the step of guiding the air flow by the leading edge of the first blade 30, thereby preventing the trailing edge of the guide vane 70 from not corresponding to the leading edge of the first blade 30, and the air flow is guided to the leeward side of the first blade 30 by the guide vane 70, resulting in unstable air flow transition.

[0082] In some embodiments, the outlet flow angle of the guide vane 70 and the inlet flow angle of the first blade 30 satisfy the following relationship: 0°≤|β1-β2|≤10°, where β1 represents the outlet flow angle of the guide vane 70, and β2 represents the inlet flow angle of the first blade 30.

[0083] By satisfying the requirement of 0°≤|β1-β2|≤10°, on the one hand, the stability and uniformity of the air flow from the guide vane 70 to the first blade 30 are ensured, and on the other hand, the air flow loss is reduced, and the air flow impact on the first blade 30 is avoided, thereby generating aerodynamic noise.

[0084] In some embodiments, the inlet flow angle of the guide vane 70 is in the range of 10°-15°.

[0085] By setting the inlet flow angle of the guide vane 70 in the range of 10°-15°, the guide vane 70 can smoothly guide the external air flow into the counter-rotating fan, and then guide it to the first blade 30, thereby preventing the external air flow from being turbulent when entering the counter-rotating fan, and improving the uniformity of the air flow entering the counter-rotating fan.

[0086] In some embodiments, the diameter of the area surrounded by the guide vane 70 is smaller than the diameter of the hub 20.

[0087] The diameter of the area surrounded by the guide vane 70 is smaller than the diameter of the hub 20, i.e., the highest point of the guide vane 70 is lower than the lowest point of the first blade 30, which helps to fully utilize the surface of the first blade 30, so that the air flow enters the first blade 30 smoothly from the guide vane 70, and ensures smooth transition of the air flow. If the diameter of the area surrounded by the guide vane 70 is greater than the diameter of the hub 20, i.e., there is an overlapping gap between the area surrounded by the rotation of the guide vane 70 and the area surrounded by the rotation of the first blade 30, when the air flow guided by the guide vane 70 overflows into the overlapping gap, it will cause air flow turbulence, and may also cause aerodynamic noise, affecting the performance of the counter-rotating fan.

[0088] In some embodiments, the number of blades of the guide vane 70 is the same as the number of blades of the first blade 30.

[0089] The number of the guide vanes 70 is the same as the number of the first vanes 30, which further ensures that the air flow is smooth and uniform when the air flow is transferred from the guide vanes 70 to the first vanes 30.

[0090] In some embodiments, the radius and the height of the cap 60 satisfy the following relationship: 0.86≤r3 / h3≤1.15, where r3 represents the radius of the cap 60, and h3 represents the height of the cap 60.

[0091] By satisfying the condition of 0.86≤r3 / h3≤1.15, the uniformity of the air flow at the inlet of the cross-flow fan is improved, and the performance of the cross-flow fan is improved, and the air supply quality of the cross-flow fan is improved.

[0092] The radius of the cap 60 is consistent with the radius of the hub 20, and the height of the cap 60 depends on the size of other equipment in the cross-flow fan. Under the condition of ensuring the condition, the greater the height of the cap 60, the more uniform the inlet air.

[0093] In some embodiments, the cross-flow fan further comprises a second vane 40 disposed on one side of the first vane 30, and the width of the second vane 40 is smaller than the width of the first vane 30.

[0094] The first vane 30 and the second vane 40 rotate to generate a pressure equivalent to two-stage fans. The first vane 30 and the second vane 40 can rotate at the same / different speed / rotation direction, so as to realize various air supply modes such as forward, reverse, long-distance, and non-inductive, and improve the flexibility of air supply.

[0095] The embodiments of the present disclosure also provide an air conditioner comprising the cross-flow fan provided by any one of the preceding embodiments. In the refrigeration or heating process, the air conditioner has the advantages of small aerodynamic noise, increased comfort of the user using the air conditioner, the air conditioner can provide long-distance and short-distance air supply options, ensure the air supply effect, improve the comfort of the air supply, and improve the overall performance of the air conditioner.

[0096] The above description and drawings are illustrative of embodiments of the present disclosure and are not intended to be limiting. Other embodiments can include structural and other changes. Embodiments are merely representative of possible variations. Individual components and functions are optional unless explicitly required, and the order of operations can be varied. Portions and features of some embodiments can be included in, or substituted for, those of other embodiments. The scope of the present disclosure encompasses the full range of equivalents of the claims, as well as all available extensions of the claims. As used in the present application, although the terms "first," "second," and the like can be used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be called a first element, without changing the meaning of the description, so long as all occurrences of the first element are renamed consistently and all occurrences of the second element are renamed consistently. The first element and the second element are both elements, but they are not necessarily the same element. Also, the use of the terms "a" and "an" and "the" and "said" in the present application are intended to include both singular and plural forms, unless the context clearly indicates otherwise. Similarly, the term "and / or" as used in the present application refers to any and all possible combinations of one or more of the associated listed items. In addition, as used in the present application, the term "comprise" and variations of the term, such as "comprises" and / or "comprising," and the like, mean the inclusion of the stated features, elements, and / or components, but not the exclusion of one or more other features, elements, components, and / or groups thereof. Unless otherwise limited, an element defined by an expression "comprising a... " does not exclude the existence of additional identical elements in the process, method, or device including the stated element. In the present document, each embodiment can focus on the differences from other embodiments, and the same or similar parts between embodiments can be referred to each other. For the method, product, etc. disclosed in the embodiments, if it corresponds to the method part of the embodiments, the relevant part can be referred to the description of the method part.

[0097] Those skilled in the art can understand that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be realized in electronic hardware or a combination of computer software and electronic hardware. Whether the functions are realized in hardware or software manner can depend on the specific application and design constraints of the technical solution. The skilled person can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the embodiments of the present disclosure. The skilled person can clearly understand that, for the convenience and brevity of the description, the specific working process of the above-described system, device and unit can refer to the corresponding process in the foregoing method embodiments, which will not be described here.

[0098] The terms "longitudinal", "transverse", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, which are only for the convenience and brevity of the description herein and the simplification of the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In the description herein, unless otherwise specified and limited, the terms "mount", "connect", "connect" should be understood broadly, for example, it can be a mechanical connection or an electrical connection, it can be a communication between two elements, it can be directly connected or indirectly connected through an intermediate medium, and the specific meaning of the above terms can be understood by the person skilled in the art according to the specific circumstances. In this paper, unless otherwise specified, the term "a plurality of" means two or more. In this paper, the term "and / or" is a description of the association between the objects, which means that there can be three relationships. For example, A and / or B means: A or B, or, A and B, three relationships.

Claims

1. A contra-rotating fan comprising a hub and first blades, characterised in that, Also comprising: a cap, which is conical, is arranged at the windward end face of the hub to guide the airflow to the first blades; a casing, which is arranged outside the first blades; a second blade, which is arranged at the hub and at one side of the first blades, and has a shorter blade length than the first blades; an inner cylinder, which is arranged between the casing and the hub and is arranged outside the second blades; the windward end face is provided with a guide vane, and the rotation direction of the guide vane is the same as that of the first blades.

2. The contra-rotating fan of claim 1, wherein The trailing edge of the guide vane corresponds to the leading edge of the first blades.

3. The contra-rotating fan of claim 1, wherein The outlet flow angle of the guide vane and the inlet flow angle of the first blades satisfy the following relationship: 0°≤|β1-β2|≤10°， Wherein, β1 represents the outlet flow angle of the guide vane, and β2 represents the inlet flow angle of the first blades.

4. The contra-rotating fan of claim 1, wherein The inlet flow angle of the guide vane is in the range of 10°-15°.

5. The contra-rotating fan of claim 1, wherein The diameter of the area surrounded by the guide vane is smaller than that of the hub.

6. The contra-rotating fan of claim 1, wherein The number of blades of the guide vane is the same as that of the first blades.

7. The contra-rotating fan of any one of claims 1 to 6, wherein, The radius and height of the cap satisfy the following relationship: 0.86≤r3 / h3≤1.15， Wherein, r3 represents the radius of the cap, and h3 represents the height of the cap.

8. The contra-rotating fan of any one of claims 1 to 6, wherein, The width of the second blades is smaller than that of the first blades.

9. An air conditioner characterized by comprising: The contra-rotating fan comprises the contra-rotating fan according to any one of claims 1-8.

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