Embedded air conditioner indoor unit and embedded air conditioner

Abstract

The invention relates to the technical field of household appliances, particularly provides an indoor unit of an embedded air conditioner and the embedded air conditioner, and aims to solve the problems of non-uniform air volume, high operation noise and low efficiency caused by the fact that the height of a heat exchanger is not matched with the size of fan blades. Therefore, the embedded air conditioner indoor unit comprises a shell, a heat exchanger and a centrifugal fan, the heat exchanger and the centrifugal fan are mounted in the shell, the heat exchanger surrounds the centrifugal fan and is opposite to an air outlet of the centrifugal fan, the centrifugal fan comprises a wheel cover and a fan wheel disc which are oppositely arranged in the vertical direction, and a plurality of blades are arranged between the wheel cover and the fan wheel disc. The height of the heat exchanger is H1, the vertical height between the outer side surface of the wheel cover and the outer side surface of the fan wheel disc is H2, and 0.67 H1 < = H2 < = 0.71 H1. Therefore, the distribution of the airflow in the vertical direction is highly matched with the coverage range of the heat exchanger, so that the heat exchange efficiency is improved, the vortex and turbulence of the airflow at the upper edge and the lower edge of the heat exchanger are reduced, and the noise is reduced.

Description

Technical Field

[0001] This invention relates to the field of household appliance technology, specifically providing an embedded air conditioner indoor unit and an embedded air conditioner. Background Technology

[0002] In public buildings with high ceilings, such as supermarkets, office buildings, and shops, ceiling-mounted air conditioners (embedded units) have become the mainstream air conditioning solution due to their advantages such as wide single-unit radiation area, abundant air volume, rapid temperature control response, and flexible installation. Their working principle is as follows: centrifugal fan blades drive indoor airflow through rotation, which flows through the indoor heat exchanger after a 90° turn, and then exits through the outlet air duct after a second 90° turn, completing the cooling / heating cycle.

[0003] Current embedded air conditioning systems primarily rely on the spatial matching between the centrifugal fan and the heat exchanger for airflow organization design. Research has found that the compatibility between the heat exchanger height and the centrifugal fan blade size directly affects the uniformity of airflow distribution and noise levels on the heat exchange surface. Specifically, insufficient compatibility between the heat exchanger height and blade size leads to uneven airflow distribution on the heat exchange surface. For example, excessively high airflow in some areas causes increased noise, while excessively low airflow in other areas results in decreased heat exchange efficiency.

[0004] Although the industry has made improvements by increasing fan power or optimizing flow channel structure, it has not fundamentally solved the parameter coupling problem between heat exchanger height and blade size, resulting in performance fluctuations of products under different installation scenarios.

[0005] Therefore, a new technical solution is needed in this field to solve the above problems. Summary of the Invention

[0006] The present invention aims to solve the above-mentioned technical problems, namely, to solve the problems of uneven air volume, high operating noise and low efficiency caused by the mismatch between the height of the heat exchanger and the size of the fan blades in existing embedded air conditioners.

[0007] In a first aspect, the present invention provides an embedded air conditioner indoor unit, including a housing, a heat exchanger and a centrifugal fan installed in the housing, the heat exchanger being arranged around the centrifugal fan and opposite to the air outlet of the centrifugal fan, the centrifugal fan including a wheel cover and a fan disc arranged opposite each other in a vertical direction, a plurality of blades being arranged between the wheel cover and the fan disc, the plurality of blades being distributed circumferentially at intervals along the fan disc, the height of the heat exchanger being H1, the vertical height between the outer surface of the wheel cover and the outer surface of the fan disc being H2, and 0.67H1≤H2≤0.71H1.

[0008] In the preferred embodiment of the above-mentioned embedded air conditioner indoor unit, the wheel cover includes an annular base and an air guide portion disposed circumferentially on the edge of the annular base. The annular base has an air inlet in the middle. The air guide portion overlaps with the blade in the vertical direction. Along the radial direction of the annular base, the line connecting the two ends of the air guide portion forms a preset angle with the horizontal plane where the annular base is located. The vertical height between the end of the air guide portion away from the annular base and the fan wheel is the air outlet height H3, where 0.71H2≤H3≤0.75H2.

[0009] In the preferred technical solution of the above-mentioned embedded air conditioner indoor unit, the preset included angle is 30° to 40°.

[0010] In the preferred embodiment of the above-mentioned embedded air conditioner indoor unit, the air guide portion is in the arc shape that bends toward one side of the blade along the radial direction of the annular base.

[0011] In the preferred embodiment of the above-mentioned embedded air conditioner indoor unit, the blades include a leading edge and a trailing edge. The leading edge is used to introduce outside air into the space between the multiple blades, and the trailing edge is used to expel the air between the multiple blades.

[0012] In two adjacent blades, one of the blades has an outlet feature line running from top to bottom on its windward surface. The outlet feature line is formed by connecting the points on the windward surface of the blade closest to the trailing edge of the adjacent blade. The trailing edge of the blade corresponds to the outlet feature line of the adjacent blade, and the two form the air outlet of the centrifugal fan. The width of the air outlet decreases first and then increases from top to bottom.

[0013] In the preferred technical solution of the above-mentioned embedded air conditioner indoor unit, among two adjacent blades, the trailing edge of one blade includes a first segment and a second segment distributed vertically. The first segment is inclined from top to bottom toward the windward side of the blade, and the second segment is inclined from top to bottom toward the leeward side of the blade. The outlet feature line of the other blade is curved into an arc shape from top to bottom toward the windward side. The first segment has a first feature point P1. The width of the air outlet is the smallest at the first feature point P1, and the width of the top of the air outlet is smaller than the width of the bottom of the air outlet.

[0014] In the preferred technical solution of the above-mentioned embedded air conditioner indoor unit, the first segment also has a second feature point P2, which is located above the first feature point P1. The second feature point P2 and the first feature point P1 divide the first segment into a first sub-segment, a second sub-segment and a third sub-segment from top to bottom, and the inclination of the first sub-segment, the second sub-segment and the third sub-segment increases sequentially.

[0015] In the preferred embodiment of the above-mentioned embedded air conditioner indoor unit, the leading edge is an arc shape with a gradually increasing tangent slope from the top end to the bottom end of the leading edge.

[0016] In the preferred embodiment of the above-mentioned embedded air conditioner indoor unit, the leading edge is inclined toward the leeward side of the blade.

[0017] In a second aspect, the present invention provides an embedded air conditioner, including an outdoor unit and an embedded air conditioner indoor unit as described in any of the above claims, wherein the outdoor unit is connected to the embedded air conditioner indoor unit.

[0018] Those skilled in the art will understand that the technical solution of the present invention provides an embedded air conditioning indoor unit, including a housing, a heat exchanger installed in the housing, and a centrifugal fan. The heat exchanger is arranged around the centrifugal fan and opposite to the air outlet of the centrifugal fan. The centrifugal fan includes a wheel cover and a fan disc arranged opposite each other in the vertical direction. Multiple blades are arranged between the wheel cover and the fan disc, and the multiple blades are distributed circumferentially around the fan disc. The height of the heat exchanger is H1, and the vertical height between the outer surface of the wheel cover and the outer surface of the fan disc is H2, where 0.67H1≤H2≤0.71H1. By adopting the above technical solution, the present invention can solve the problems of uneven airflow, high operating noise, and low efficiency caused by the mismatch between the height of the heat exchanger and the size of the fan blades. Specifically, by precisely controlling the fan blade height H2 to be between 0.67 and 0.71 times the heat exchanger height H1, the vertical distribution range of the airflow generated by the fan is highly matched with the area that the heat exchanger needs to cover. The airflow can cover the entire vertical height of the heat exchanger more evenly, thereby improving the heat exchange efficiency. In addition, it can also reduce the stripping, eddy currents and turbulence of the airflow at the upper and lower edges of the heat exchanger, and avoid the impact noise generated by the high-speed airflow directly hitting the structure outside the heat exchanger range.

[0019] Furthermore, in this invention, the wheel cover includes an annular base and an air guide portion disposed circumferentially along the edge of the annular base. The annular base has an air inlet in the middle. The air guide portion overlaps with the blades in the vertical direction. Along the radial direction of the annular base, the line connecting the two ends of the air guide portion forms a predetermined angle with the horizontal plane containing the annular base. The vertical height between the end of the air guide portion away from the annular base and the fan disc is the outlet height H3, where 0.71H2≤H3≤0.75H2. This arrangement further ensures that the airflow can smoothly and efficiently transition into the outlet chamber between the heat exchanger and the centrifugal fan, minimizing airflow loss and noise generation in the outlet chamber.

[0020] Furthermore, in this invention, the air guide section is curved towards one side of the blade along the radial direction of the annular base. This design makes the airflow entering the outlet chamber more evenly and smoothly distributed in both the circumferential and axial directions, thereby further increasing the airflow volume and reducing noise. Attached Figure Description

[0021] The preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

[0022] Figure 1 This is a schematic diagram of the structure of the embedded air conditioner indoor unit of the present invention;

[0023] Figure 2 This is a cross-sectional view of the embedded air conditioner indoor unit of the present invention;

[0024] Figure 3 This is a schematic diagram of the centrifugal fan of the present invention;

[0025] Figure 4 This is a front view of the centrifugal fan of the present invention;

[0026] Figure 5 This is a schematic diagram showing the positional relationship between the trailing edge and the exit feature line of the present invention.

[0027] List of reference numerals in the attached diagram:

[0028] 1. Shell;

[0029] 2. Heat exchanger;

[0030] 3. Centrifugal fan; 31. Wheel cover; 311. Annular base; 312. Air guide; 313. Air inlet; 32. Fan wheel; 33. Blade; 331. Leading edge; 332. Trailing edge; 3321. First section; 3322. Second section; 333. Outlet feature line; 34. Air outlet. Detailed Implementation

[0031] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the invention and are not intended to limit the scope of protection of the invention. For example, although the following embodiments are described in conjunction with an embedded air conditioning unit, the embedded air conditioning unit provided by the present invention is also applicable to other products that need to solve the problems of uneven airflow, high operating noise, and low efficiency caused by the mismatch between the heat exchanger height and the fan blade size.

[0032] It should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly, for example, they can refer to a fixed connection, a detachable connection, or an integral connection. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] Based on the background art, existing embedded air conditioners suffer from uneven airflow, high operating noise, and low efficiency due to the mismatch between the heat exchanger height and fan blade size. This invention provides an embedded air conditioner indoor unit, aiming to effectively solve these problems by rationally setting the distance between the centrifugal fan and the heat exchanger.

[0034] like Figures 1 to 3 As shown, the present invention provides an embedded air conditioner indoor unit, including a housing 1, a heat exchanger 2 and a centrifugal fan 3 installed in the housing 1. The heat exchanger 2 is arranged around the centrifugal fan 3 and is arranged opposite to the air outlet 34 of the centrifugal fan 3. The centrifugal fan 3 includes a wheel cover 31 and a fan disc 32 arranged opposite each other in the vertical direction. A plurality of blades 33 are arranged between the wheel cover 31 and the fan disc 32. The plurality of blades 33 are distributed at intervals along the circumference of the fan disc 32. The height of the heat exchanger 2 is H1, and the vertical height between the outer surface of the wheel cover 31 and the outer surface of the fan disc 32 is H2, where 0.67H1≤H2≤0.71H1.

[0035] In traditional designs, if H2 is much smaller than H1, the airflow generated by the fan can only cover the central area of ​​heat exchanger 2. The airflow velocity in the upper and lower parts of heat exchanger 2 (near the wheel cover 31 and fan wheel 32) is very low or even forms a dead zone, causing the heat exchange capacity in these areas to be ineffective. Conversely, if H2 is much larger than H1, part of the airflow generated by the fan will directly blow onto the shell 1 or cavity outside the range of heat exchanger 2, resulting in energy waste and ineffective flow. At the same time, it will also make the actual airflow distribution through heat exchanger 2 uneven, reducing the effective heat exchange area.

[0036] Furthermore, when H2 and H1 are mismatched, the airflow is prone to sudden flow separation at the upper / lower edge of the heat exchanger 2 after leaving the fan blade 33. This results in extremely uneven velocity distribution of the airflow on the surface of the heat exchanger 2, generating strong eddies and turbulence, and causing a lot of noise.

[0037] This invention precisely controls the height H2 of the fan blade zone 33 to be between 0.67 and 0.71 times the height H1 of the heat exchanger 2. The vertical distribution range of the airflow generated by the fan is highly adapted to the area that the heat exchanger 2 needs to cover. The airflow can cover the entire vertical height of the heat exchanger 2 more evenly, avoiding serious low-speed airflow zones or dead zones in the upper and lower parts of the heat exchanger 2. At the same time, it also avoids a large amount of airflow impacting structures outside the range of the heat exchanger 2, thereby making the wind speed distribution on the entire fin surface of the heat exchanger 2 more uniform.

[0038] Uniform airflow coverage means that almost all the fin surface area of ​​heat exchanger 2 can effectively participate in heat exchange, making full use of the capacity of heat exchanger 2. The design of 0.67H1≤H2≤0.71H1 ensures that most of the airflow generated by the fan can effectively flow through heat exchanger 2, thereby improving heat exchange efficiency.

[0039] In addition, the uniform airflow distribution and suitable size relationship greatly reduce the stripping, eddy currents and turbulence of airflow at the upper and lower edges of heat exchanger 2, and avoid the impact noise generated by high-speed airflow directly hitting the structure outside the range of heat exchanger 2, so that the aerodynamic noise generated by the indoor unit of the air conditioner during operation is significantly reduced.

[0040] Preferably, such as Figures 2 to 4 As shown, the wheel cover 31 includes an annular base 311 and an air guide 312 disposed circumferentially on the edge of the annular base 311. The annular base 311 has an air inlet 313 in the middle. The air guide 312 overlaps with the blade 33 in the vertical direction. Along the radial direction of the annular base 311, the line connecting the two ends of the air guide 312 forms a preset angle with the horizontal plane where the annular base 311 is located. The vertical height between the end of the air guide 312 away from the annular base 311 and the fan wheel 32 is the air outlet height H3 of the air outlet 34, where 0.71H2≤H3≤0.75H2.

[0041] In this invention, the air guide 312 overlaps with the blade 33 below in the vertical direction (axial direction). This means that the air guide 312 extends above the rotation trajectory of the blade 33, covering a portion of the height of the blade 33. Furthermore, along the radial direction of the annular base 311, a line connecting the two ends of the air guide 312 forms a predetermined angle with the horizontal plane where the annular base 311 is located. Thus, the air guide 312 in this invention is inclined, which allows the airflow to turn more gently and guides the radial airflow more smoothly. This avoids sudden changes in direction and airflow separation when high-speed airflow hits the edge of the wheel cover 31, thus preventing the formation of strong vortices and further reducing noise.

[0042] In this invention, the vertical distance between the outermost end of the air guide section 312 (the end furthest from the annular base 311) and the outer surface of the fan impeller 32 is defined as the outlet height H3 of the air outlet 34. That is, H3 is the axial height at which the airflow actually flows out effectively from the fan impeller. 0.71H2≤H3≤0.75H2 ensures that the airflow can smoothly and efficiently transition into the outlet chamber between the heat exchanger 2 and the centrifugal fan 3, minimizing airflow loss and noise generation in the outlet chamber.

[0043] Preferably, the preset included angle is 30° to 40°.

[0044] The tilt angle range of 30° to 40° provides the optimal curvature, allowing high-speed radial airflow to change direction smoothly and gradually, significantly reducing airflow impact losses, flow separation losses, and vortex dissipation. This converts more of the fan's input energy into useful air pressure and air volume, improving the fan's aerodynamic efficiency, reducing airflow instability and potential backflow, and helping to maintain a more stable airflow output and more uniform airflow.

[0045] In addition, the 30° to 40° angle range ensures that the airflow enters the oral cavity smoothly in a more uniform and design-compliant direction, reducing turbulent noise caused by sudden speed changes, directional disturbances, and local eddies at the oral cavity, thus improving user comfort.

[0046] Preferably, such as Figure 2 and Figure 4 As shown, along the radial direction of the annular base 311, the air guide 312 is in the shape of an arc that bends toward the blade 33.

[0047] Understandably, the arc-shaped air guide 312 is essentially a streamlined design. It conforms to the inherent and natural flow trajectory of the high-speed airflow ejected from the tip of the centrifugal fan 3 blades 33, allowing the airflow to flow extremely smoothly and without separation along the surface of the air guide 312 and turn into the outlet chamber between the heat exchanger 2 and the centrifugal fan 3, making the airflow entering the outlet chamber more evenly distributed in both the circumferential and axial directions.

[0048] Furthermore, a smoother, non-separating airflow means lower turbulence intensity in the airflow, and the noise generated when the smoother airflow enters the oral cavity and rubs against the air will also be reduced accordingly.

[0049] Preferably, such as Figures 3 to 5As shown, the blade 33 includes a leading edge 331 and a trailing edge 332. The leading edge 331 is used to introduce outside air into the space between the multiple blades 33, and the trailing edge 332 is used to exhaust the air between the multiple blades 33. In two adjacent blades 33, one blade 33 has an outlet feature line 333 from top to bottom on its windward surface. The outlet feature line 333 is formed by connecting the points on the windward surface of the blade 33 that are closest to the trailing edge 332 of the adjacent blade 33. The trailing edge 332 of the blade 33 corresponds to the outlet feature line 333 of the adjacent blade 33, and the two form the air outlet 34 of the centrifugal fan. The width of the air outlet 34 decreases and then increases from top to bottom.

[0050] For example, for each blade 33, a "virtual line" is found on its pressure surface (windward side). Each point on this line is the closest point to the trailing edge 332 of the adjacent blade 33. Connecting these "closest points" yields the outlet feature line 333. Compared to the prior art, the outlet 34 is no longer a simple "trailing edge 332-trailing edge 332" channel, but a three-dimensional slit formed by the trailing edge 332 and the outlet feature line 333.

[0051] During operation, the centrifugal fan 3 of this invention draws gas in through the inlet 313, and after the blades 33 perform work, it flows radially out. Because the width of the outlet 34 is non-uniformly distributed along the vertical direction (the height direction of the blades 33) in a "contraction-expansion" pattern (similar to an hourglass shape), the contraction section increases the airflow velocity, reduces the boundary layer displacement thickness, and lowers blockage; the expansion section avoids flow separation caused by excessive expansion. Therefore, at the same rotational speed and power consumption, the effective flow area is increased, and the airflow is improved.

[0052] In addition, in traditional fans, the air outlet area of ​​each layer at the same blade height 33 is the same, but due to the influence of boundary layer and radial pressure gradient, the flow rate at the top and bottom is different, resulting in discrete noise. This design makes the width of the air outlet 34 "decreases first and then increases" from top to bottom, so that the outlet area at each axial position matches the actual flow rate, thereby "flattening" the flow peak and balancing the flow rate in each area, thus significantly reducing discrete frequency noise.

[0053] Preferably, such as Figure 5 As shown, in two adjacent blades 33, the trailing edge 332 of one blade 33 includes a first segment 3321 and a second segment 3322 distributed vertically. The first segment 3321 is inclined from top to bottom toward the windward side of the blade 33, and the second segment 3322 is inclined from top to bottom toward the leeward side of the blade 33. The outlet feature line 333 of the other blade 33 is curved into an arc from top to bottom toward the windward side. The first segment 3321 has a first feature point P1. The width of the air outlet 34 is the smallest at the first feature point P1, and the width of the top of the air outlet 34 is smaller than the width of the bottom of the air outlet 34.

[0054] Understandably, in two adjacent blades 33, the first segment 3321 of one blade 33 tilts downwards towards the windward side (the pressure side of the blade 33), while the second segment 3322 tilts downwards towards the leeward side (the suction side of the blade 33). Overall, the trailing edge 332 is shaped like an "S" or an inverted "S," resulting in different angles and distances between the trailing edge 332 and the exit feature line 333 at different axial heights. The exit feature line 333 on the other blade 33 is an arc curving downwards towards the windward side, which dynamically matches the segmented structure of the trailing edge 332 of the adjacent blade 33. This arc design coordinates the tilt angle of the exit feature line 333 with that of the first segment 3321, guiding the airflow along a specific path.

[0055] The first section 3321 is tilted towards the windward side, allowing the airflow to transition along a smoother path when leaving the blade 33, reducing airflow separation at the trailing edge 332; the second section 3322 is tilted towards the leeward side, forming an expansion channel that allows the airflow to fully diffuse after leaving the blade 33, suppressing the formation of wake vortices. This significantly reduces the intensity of the vortex at the trailing edge 332, thereby significantly reducing energy loss.

[0056] The arc-shaped structure of the outlet feature line 333 matches the inclination angle of the first segment 3321 of the trailing edge 332, forming a "contraction-expansion" flow channel structure. The airflow accelerates when passing through the narrowest point (P1), and then decelerates and pressurizes in the expansion section, conforming to the Venturi effect principle. This makes the pressure distribution at the outlet 34 more uniform, avoiding backflow caused by local high-pressure areas or airflow adsorption caused by low-pressure areas.

[0057] Furthermore, the width of the air outlet 34 is smallest at P1, forming a "throat" structure that accelerates airflow and enhances centrifugal projection capability; the narrower width at the top maintains high-speed airflow, while the wider width at the bottom allows more gas to be discharged, resulting in an overall increase in air volume. Compared to a traditional air outlet 34 with a uniform width, this design can significantly increase air volume.

[0058] Preferably, such as Figure 5 As shown, the first segment 3321 also has a second feature point P2, which is located above the first feature point P1. The second feature point P2 and the first feature point P1 divide the first segment 3321 into a first sub-segment, a second sub-segment, and a third sub-segment from top to bottom, and the inclination of the first sub-segment, the second sub-segment, and the third sub-segment increases sequentially.

[0059] This invention divides the first segment 3321 into three sub-segments with progressively increasing inclination, allowing the airflow to undergo a gradual process as it passes through each segment. This design conforms to the principle of "laminar acceleration" in fluid dynamics, preventing separation or vortices caused by sudden contraction or expansion of the airflow. This makes the contraction and expansion gradient of the air outlet 34 from top to bottom smoother, avoiding uneven flow caused by excessively rapid contraction and expansion in local areas, thereby improving acceleration efficiency.

[0060] Preferably, both the first segment 3321 and the second segment 3322 are Bézier curves or B-spline curves.

[0061] By using Bézier curves or B-spline curves for both the first segment 3321 and the second segment 3322, high-order continuity within the curve and between segments is ensured, providing an extremely smooth flow guiding surface, significantly improving flow stability, suppressing turbulence and separation, and effectively reducing high-frequency noise induced by geometric factors.

[0062] It should be noted that in other embodiments, the first segment 3321 and the second segment 3322 can also be straight segments. The present invention does not limit the specific shape of the first segment 3321 and the second segment 3322, as long as it can satisfy the requirements of reducing the noise of the centrifugal fan 3 during operation and improving the uniformity of the air volume and air flow.

[0063] Preferably, such as Figure 3 As shown, from the top of the leading edge 331 to the bottom of the leading edge 331, the leading edge 331 is an arc with a gradually increasing tangent slope.

[0064] From the top to the bottom of the leading edge 331, the leading edge 331 is an arc with a gradually increasing tangential slope. In this embodiment, it means that along the height direction of the blade 33, from the top near the wheel cover 31 to the bottom near the fan disc 32, the tangential slope of the leading edge 331 gradually increases. That is, near the wheel cover 31 (top), the leading edge 331 is relatively gentle, and near the fan disc 32 (bottom), the leading edge 331 is relatively steep. From the top to the bottom, the curvature of the leading edge 331 gradually becomes steeper in a continuous and smooth manner.

[0065] This invention designs a steeper leading edge 331 near the bottom of the fan disc 32, better matching the relative velocity direction when the airflow relative velocity is low at that point. This significantly reduces the angle of attack when the airflow enters the blade 33 flow channel, bringing it closer to the ideal small or zero angle of attack state. As a result, the airflow can adhere more smoothly to the suction surface of the blade 33, eliminating separation vortices and allowing airflow to effectively pass through the bottom area of ​​the flow channel. The increased effective flow area and reduced flow losses improve the fan's volumetric efficiency, effectively eliminating intake noise and significantly increasing the intake and exhaust airflow.

[0066] Near the top of the wheel cover 31, the leading edge 331 is designed to be relatively gentle (with a small tangential slope). This is more suitable for the relative velocity direction when the relative airflow velocity is relatively high at this location. As a result, the airflow impact and possible minor separation in the blade tip area are reduced. The gentle leading edge 331 at the top helps the airflow enter smoothly, avoids the noise caused by the sudden impact of air on the blade 33, and makes the airflow intake more reasonable and uniform along the entire height direction of the blade 33 (from the wheel cover 31 to the fan disc 32).

[0067] Preferably, the leading edge 331 is tilted toward the leeward side of the blade 33.

[0068] When airflow rushes toward the leading edge 331 of a stationary or rotating blade 33 at a certain angle, if the airflow direction does not match the tangential direction of the leading edge 331, a strong airflow impact will be generated. This impact not only consumes energy, but is also the main source of high-frequency noise (hissing, whistling).

[0069] By tilting the leading edge 331 toward the leeward side, this invention can significantly reduce the angle of attack of the airflow impacting the leading edge 331 of the blade 33, allowing the airflow to flow more smoothly and closely into the flow channel between the blades 33, giving the air a more suitable direction and speed when entering the area of ​​the blade 33, further optimizing the air introduction process and helping to improve the fan's suction capacity.

[0070] Furthermore, the tilt of the leading edge 331 towards the leeward side allows for a smoother transition when air enters the blade 33 area from the outside. The air is not suddenly obstructed by the leading edge 331 of the blade 33, preventing strong impacts and pressure changes. This smooth transition reduces noise caused by sudden pressure changes, making the fan quieter during operation.

[0071] In addition, the present invention provides an embedded air conditioner, including an outdoor unit and the aforementioned embedded air conditioner indoor unit, wherein the outdoor unit is connected to the embedded air conditioner indoor unit.

[0072] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. An embedded air conditioner indoor unit, characterized in that, The device includes a housing (1), a heat exchanger (2) installed in the housing (1), and a centrifugal fan (3). The heat exchanger (2) is arranged around the centrifugal fan (3) and is opposite to the air outlet (34) of the centrifugal fan (3). The centrifugal fan (3) includes a wheel cover (31) and a fan disc (32) arranged opposite each other in the vertical direction. A plurality of blades (33) are arranged between the wheel cover (31) and the fan disc (32). The plurality of blades (33) are distributed circumferentially along the fan disc (32). The height of the heat exchanger (2) is H1, and the vertical height between the outer surface of the wheel cover (31) and the outer surface of the fan disc (32) is H2, where 0.67H1≤H2≤0.71H1.

2. The embedded air conditioner indoor unit according to claim 1, characterized in that, The wheel cover (31) includes an annular base (311) and a guide section (312) arranged circumferentially around the edge of the annular base (311). The annular base (311) has an air inlet (313) in the middle. The guide section (312) overlaps with the blade (33) in the vertical direction. Along the radial direction of the annular base (311), the line connecting the two ends of the guide section (312) forms a preset angle with the horizontal plane where the annular base (311) is located. The vertical height between the end of the guide section (312) away from the annular base (311) and the fan wheel (32) is the air outlet height H3 of the air outlet (34), where 0.71H2≤H3≤0.75H2.

3. The embedded air conditioner indoor unit according to claim 2, characterized in that, The preset included angle is 30° to 40°.

4. The embedded air conditioner indoor unit according to claim 2, characterized in that, Along the radial direction of the annular base (311), the air guide (312) is curved toward the side of the blade (33).

5. The embedded air conditioner indoor unit according to claim 1, characterized in that, The blade (33) includes a leading edge (331) and a trailing edge (332). The leading edge (331) is used to introduce outside air between the multiple blades (33), and the trailing edge (332) is used to expel air between the multiple blades (33). In two adjacent blades (33), one of the blades (33) has an outlet feature line (333) from top to bottom on its windward surface. The outlet feature line (333) is formed by connecting the points on the windward surface of the blade (33) that are closest to the trailing edge (332) of the adjacent blade (33). The trailing edge (332) of the blade (33) corresponds to the outlet feature line (333) of the adjacent blade (33), and the two form the air outlet (34) of the centrifugal fan (3). The width of the air outlet (34) decreases first and then increases from top to bottom.

6. The embedded air conditioner indoor unit according to claim 5, characterized in that, In two adjacent blades (33), the trailing edge (332) of one blade (33) includes a first segment (3321) and a second segment (3322) distributed vertically. The first segment (3321) is inclined from top to bottom toward the windward side of the blade (33), and the second segment (3322) is inclined from top to bottom toward the leeward side of the blade (33). The outlet feature line (333) of the other blade (33) is curved into an arc from top to bottom toward the windward side. The first segment (3321) has a first feature point P1. The width of the air outlet (34) is the smallest at the first feature point P1, and the width of the top of the air outlet (34) is smaller than the width of the bottom of the air outlet (34).

7. The embedded air conditioner indoor unit according to claim 6, characterized in that, The first segment (3321) also has a second feature point P2, which is located above the first feature point P1. The second feature point P2 and the first feature point P1 divide the first segment (3321) into a first sub-segment, a second sub-segment and a third sub-segment from top to bottom, and the inclination of the first sub-segment, the second sub-segment and the third sub-segment increases sequentially.

8. The embedded air conditioner indoor unit according to claim 5, characterized in that, From the top end of the leading edge (331) to the bottom end of the leading edge (331), the leading edge (331) is an arc with a gradually increasing tangent slope.

9. The embedded air conditioner indoor unit according to claim 8, characterized in that, The leading edge (331) is inclined toward the leeward side of the blade (33).

10. An embedded air conditioner, characterized in that, It includes an outdoor unit and an embedded air conditioning indoor unit as described in any one of claims 1 to 9, wherein the outdoor unit is connected to the embedded air conditioning indoor unit.

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