Novel low-noise cross-flow fan

Abstract

The invention discloses a novel low-noise cross-flow fan, and relates to the technical field of electromechanics. The centrifugal fan comprises a motor 1, an impeller, an impeller shaft 10, a bearing assembly and a machine shell assembly 3. The bearing assembly comprises a sliding bearing seat 12 and a sliding bearing 11 embedded in the sliding bearing seat 12, and an impeller shaft 10 at the left end of the impeller is installed in the sliding bearing 11 of the bearing assembly in a penetrating mode. The diameter of the left part of the impeller shaft 10 arranged in the sliding bearing 11 in a penetrating manner is 2.0-3.5 mm, the aperture of the sliding bearing 11 is 2.0-3.5 mm, and the fit clearance between the left part of the impeller shaft 10 and the sliding bearing 11 is 2-7 microns; the cross-flow fan has the advantages of being small in vibration, low in noise, high in efficiency, low in cost and the like, is suitable for the cross-flow fan with the impeller outer diameter ranging from 30 mm to 60 mm, and is used in cooperation with household appliances such as a refrigerator, a display cabinet, a cold air fan, a warm air blower, an electric fireplace, an air curtain machine and an embedded oven.

Description

Technical Field

[0001] The invention relates to the field of electromechanical technology, in particular to a novel low-noise crossflow fan. Background Art

[0002] Crossflow fan, also known as crossflow fan, is a type of fan designed based on centrifugal force and fan impeller. Its working principle is to push air to the exhaust port of the fan through the centrifugal force generated by the rotation of the impeller, so as to realize the delivery of air flow and the adjustment of air volume. Because of its characteristics of high pressure and small air volume, it is widely used in air conditioning systems, ventilation equipment, air circulation in industrial production processes and other fields.

[0003] The impeller of the crossflow fan is multi-blade, long cylindrical, with forward multi-wing blades. When the impeller rotates, the airflow enters the blade grid from the opening of the impeller, passes through the inside of the impeller, and is discharged into the volute from the other side of the blade grid to form the working airflow.

[0004] The impeller outer diameter of the existing cross-flow fans used in home appliances such as heaters, fireplaces, and air conditioners is mostly 30-60mm, and the main geometric parameters of the impeller are: the inner blade angle β1 is 90-97°, the outer blade angle β2 is 22-30°, the diameter ratio D1 / D2=0.8-0.86, and the relative pitch t / b=0.94-1.0. At the same time, the shaft diameter of the impeller shaft is mostly 4.0 (-0.01 / -0.02) mm, and it is matched with a sliding bearing with an aperture of 4.0 (+0.01 / +0.004) mm. The theoretical contact area between the impeller shaft and the inner hole of the bearing is 67.86 mm. 2 The fit clearance is 7μm to 15μm, which makes the fit system of the impeller and the bearing seat unstable and easily generates harmful noise.

[0005] The Chinese patent (patent application number 201110091068.1) discloses a "crossflow fan with a composite profile blade impeller", which is composed of a motor 1, a coupling 2, an impeller, a casing assembly 7 and a bearing seat 8; the impeller is composed of a left wheel disc 6, a middle wheel disc 4, a right wheel disc 3 and an impeller shaft 9 and more than two blades 5, and the inner profile of the cross-section of the blade 5 is a composite profile in which a section of an arc is tangent to an outer peripheral straight line section or a section of an arc is tangent to an inner peripheral straight line section; it has the characteristics of greatly improved total pressure efficiency of the fan and significantly reduced noise compared to A sound level, and is suitable for cooling and heat dissipation of various equipment, ventilation and air exchange in rooms, public places, and vehicles, constant temperature and drying machinery, heating and cooling equipment, and household appliances such as freezers and display cabinets, air conditioners, heaters, electric fireplaces, air curtain machines, and built-in ovens.

[0006] Another Chinese patent (patent application number 201220366829.X) discloses a "crossflow impeller, crossflow fan and wall-mounted air conditioner", in which the crossflow impeller includes a plurality of blades arranged at intervals in the circumferential direction, the blades having a pressure surface and a suction surface, and the profile of the pressure surface is a concave curve, the profile of the suction surface is a convex curve, and the radius of curvature of the profile of the pressure surface and / or the middle of the profile of the suction surface is smaller than the radius of curvature of the two ends. Since the pressure surface and / or the suction surface of the fan blade adopts a curve design with different curvature radii, the conventional single arc arc design of the existing fan blade is changed, the airflow separation in the fan blade flow channel is reduced, and the aerodynamic noise caused by separation and secondary flow is effectively reduced. In this way, on the basis of ensuring the work capacity, the airflow can flow through the blade more smoothly, avoiding the shedding of the vortex in the blade, reducing the aerodynamic noise, and improving the comfort of air conditioning use.

[0007] There is also a "crossflow fan impeller center disk" disclosed in a Chinese patent (patent application number 200920117579.4), wherein the crossflow fan impeller center disk has a disk body (1) in a circular shape, and is provided with a shaft bearing rubber mounting port and a plurality of blade insertion holes (2) on the disk body (1), and the blade insertion holes (2) are regularly arranged along the circumferential direction of the disk body (1), and the blade insertion holes (2) are composed of an upper end insertion hole (21), a middle end insertion hole (22) and a lower end insertion hole (23), and the shapes of the upper end insertion hole (21) and the lower end insertion hole (23) are symmetrical along the center of the blade insertion hole (2), and the aperture distance (L1) of the upper end insertion hole (21) and the lower end insertion hole (23) is greater than the aperture distance (L2) at the upper and lower ends of the middle end insertion hole (22). The crossflow fan impeller center disk has the advantages of convenient and rapid blade insertion into the blade insertion hole, the center disk is not easy to deform, and the impeller made of the center disk has low noise and high torque.

[0008] There is also a Chinese patent (patent application number 201120465704.8) that discloses "an impeller for a crossflow fan", which includes an impeller composed of a single-section wheel, the single-section wheel includes two circular chassis and blades arranged in parallel, the blades are arranged between the two chassis along the circumferential direction of the chassis, the impeller includes one or more double-section wheels, the double-section wheels are composed of an upper single-section wheel and a lower single-section wheel, the blades of the upper single-section wheel are spirally arranged between the upper chassis and the middle chassis in a clockwise direction, and the blades of the lower single-section wheel are spirally arranged between the middle chassis and the lower chassis in a counterclockwise direction. This impeller is composed of two single-section wheels spirally arranged in opposite directions, which effectively reduces the axial wind flow in the impeller, thereby reducing energy consumption. The axial twisting of two adjacent sections of the blades in opposite directions is used to offset the axial airflow caused by the crossflow fan blades due to the unequal distribution and / or oblique crossflow, thereby effectively reducing the noise level.

[0009] There is also a "cross-flow fan, fan and air conditioner" disclosed in a Chinese patent (patent application number is 202010763659.8), which includes an impeller, a volute and a volute tongue, and is characterized in that the cross-flow fan also includes a guide device, which includes a guide member with a blowing end and a suction end located inside the impeller. When the impeller rotates around the axis, the guide member does not rotate with the impeller, and, on a cross section perpendicular to the axis, the angle between the first straight line passing through the axis center of the axis and the end point of the blowing end and the second straight line passing through the axis center of the axis and the end point of the front end of the volute tongue is between 0° and 25°; this type of cross-flow fan can prevent the airflow from forming eccentric vortices and ensure efficient output of the airflow, which is beneficial to reducing its noise and improving its efficiency; at the same time, the present invention also provides a fan and an air conditioner having such a cross-flow fan. Summary of the invention

[0010] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a cross-flow fan with small vibration, low noise, high efficiency and low cost.

[0011] In order to solve the above technical problems, the technical solution adopted by the present invention is to invent a new type of low-noise crossflow fan: including a motor 1, an impeller, an impeller shaft 10, a bearing assembly and a casing assembly 3; the bearing assembly includes a sliding bearing seat 12 and a sliding bearing 11 embedded therein, the impeller shaft 10 is arranged in the middle of the left end of the impeller, and the motor 1 and the bearing assembly are respectively arranged in the right part and the middle of the left end of the casing assembly 3; the impeller is arranged in the casing assembly 3, and the impeller shaft 10 at its left end is inserted into the sliding bearing 11 of the bearing assembly, and the right end is connected to the motor output shaft 2 of the motor 1; the diameter of the left part of the impeller shaft 10 inserted into the sliding bearing 11 is 2.0-3.5mm, the aperture of the sliding bearing 11 is 2.0-3.5mm, and the fitting clearance between the two is 2μm~7μm.

[0012] The diameter of the left portion of the impeller shaft 10 is 2.0-3.0 mm, the aperture of the sliding bearing 11 is 2.0-3.0 mm, and the matching clearance between the two is 2 μm to 7 μm.

[0013] The diameter of the left portion of the impeller shaft 10 is 2.5 mm, the aperture of the sliding bearing 11 is 2.5 mm, and the matching clearance between the two is 2 μm to 7 μm.

[0014] The impeller includes an impeller left disk 8, an impeller middle disk 7, an impeller right disk 5, an impeller sleeve 9, a coupling 4, an impeller shaft 10 and more than two blades 6, the blades 6 are sequentially inserted into the blade grooves around the impeller left disk 8, the impeller middle disk 7 and the impeller right disk 5, the impeller sleeve 9 with the impeller shaft 10 and the coupling 4 are respectively arranged in the middle of the impeller left disk 8 and the impeller right disk 5; the left end of the motor output shaft 2 is connected to the coupling 4.

[0015] The blade 6 is arc-shaped, and its outer circumference angle β is 60-90°.

[0016] Optimally, the outer circumferential angle β of the blade 6 is 78°.

[0017] The diameter ratio D1 / D2 of the impeller is 0.68-0.85, and the relative pitch t / c of ​​the impeller is 0.87-1.13.

[0018] Optimally, the diameter ratio D1 / D2 of the impeller is 0.728, and the relative pitch t / c of ​​the impeller is 1.0.

[0019] The impeller blades 6 are relative to the impeller center disk 7, and the angle γ of the blade chord length direction relative to the line connecting the intersection of the blade inner circle and the center of the impeller center disk 7 is 20-35°.

[0020] Optimally, the angle γ between the blade chord length direction and the line connecting the intersection of the blade inner circle and the center of the impeller center disk 7 is 31°.

[0021] The novel low-noise crossflow fan of the present invention reduces the diameter of the impeller shaft from the existing φ4.0mm to φ2.5, and also reduces the inner hole diameter of the sliding bearing matched therewith from the existing φ4.0mm to φ2.5, so that the contact area between the impeller shaft and the inner hole of the sliding bearing is reduced from the original 67.86mm 2 , the fit clearance is reduced from 7μm to 15μm to 42.41mm 2 and 2μm~7μm, thereby reducing the radial movement of the impeller shaft relative to the inner hole of the sliding bearing, thereby reducing the outer circle runout during the movement of the impeller and reducing the vibration of the whole machine. At the same time, according to the linear velocity calculation formula V=ω×r, at the same angular velocity, the linear velocity of the impeller shaft relative to the outer circumference of the inner hole of the sliding bearing will drop to 0.625 times the original. In addition, due to the increase in the deflection angle of the blades in the impeller relative to the impeller center disk, the internal pressure of the impeller is less at the same speed, thus significantly reducing the noise of the fan. In addition, due to the reduction in the diameter of the impeller shaft, the friction resistance is also reduced, and the required power is also reduced, which increases the efficiency of the motor by 10%, and then reduces the copper consumption of the motor by about 15%, thereby reducing the production cost. The following table is a test comparison table of the main parameters of cross-flow fans using impellers with different impeller shaft diameters:

[0022]

[0023] BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is an exploded schematic diagram of the present invention;

[0025] Figure 2 It is a main cross-sectional schematic diagram of the present invention;

[0026] Figure 3 It is an enlarged schematic cross-sectional view along the AA axis of the present invention.

[0027] In the figure:

[0028] 1 is the motor, 2 is the motor output shaft, 3 is the housing assembly, 4 is the coupling, 5 is the right disk of the impeller, 6 is the blade, 7 is the middle disk of the impeller, 8 is the left disk of the impeller, 9 is the impeller sleeve, 10 is the impeller shaft, 11 is the sliding bearing, and 12 is the sliding bearing seat;

[0029] c is the total chord length of the blade pressure surface profile, t is the blade pitch on the outer periphery of the impeller, β is the blade outer circumferential angle (i.e. the arc angle of the blade), γ is the included angle (i.e. the angle between the blade chord length direction and the line connecting the intersection of the blade inner circle and the center of the impeller disk), D1 is the impeller inner diameter, and D2 is the impeller outer diameter. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and embodiments. The following description is in the form of examples, but the protection scope of the present invention should not be limited thereto.

[0031] In this manual and the attached Figure 2 The directions in the table are as follows:

[0032] Figure 2 The left and right are the actual left and right directions, the top and bottom are the actual top and bottom, and the front and inside are the actual front and back directions.

[0033] The novel low-noise crossflow fan of this embodiment is composed of a motor 1, an impeller, an impeller shaft 10, a bearing assembly and a casing assembly 3.

[0034] The casing assembly 3 is formed by riveting the volute plate, the volute tongue plate and the side plates at both ends. The sliding bearing seat 12 of the bearing assembly is arranged in the middle hole of the left side plate of the casing assembly 3, and the sliding bearing 11 is embedded in the sliding bearing seat 12. The motor 1 is arranged at the right part of the casing assembly 3 and connected to it as a whole. The motor output shaft 2 of the motor 1 extends from the left end of the motor 1 and passes through the middle hole of the right side plate of the casing assembly 3.

[0035] The impeller is composed of an impeller left disk 8, an impeller middle disk 7, an impeller right disk 5, an impeller sleeve 9, a coupling 4, an impeller shaft 10 and two or more (20 in this example) blades 6.

[0036] The blade 6 is an elongated circular arc-shaped piece, and its outer circumferential angle β is 60-90° (its optimized outer circumferential angle β is 78°). All blades 6 are evenly distributed in a circumferential shape and are successively installed in the blade grooves around the impeller left disk 8, the impeller middle disk 7 and the impeller right disk 5, so that the impeller diameter ratio (i.e.: the ratio of the impeller inner diameter D1 to the impeller outer diameter D2) D1 / D2 is 0.68-0.85 (its optimized diameter ratio is 0.72 8); at the same time, the relative pitch of the impeller (i.e., the ratio of the pitch t of the impeller outer periphery blades to the total chord length c of the blade pressure surface profile) t / c should be 0.87-1.13 (the optimized relative pitch is 1.0); and, the angle γ between the blade 6 of the impeller and the impeller center disk 7 and the line connecting the intersection of the blade inner circle and the center of the impeller center disk 7 should be 20-35° (the optimized angle γ is 31°).

[0037] The impeller sleeve 9 and the coupling 4 are respectively arranged in the middle of the impeller left disk 8 and the impeller right disk 5. The left end of the motor output shaft 2 passes through the middle hole of the coupling 4 and is integrated with it; the right end of the impeller shaft 10 passes through the shaft hole of the impeller sleeve 9 (let the impeller shaft 10 and the impeller sleeve 9 be riveted together), and its left end passes through the shaft hole of the sliding bearing 11.

[0038] The diameter of the left part of the impeller shaft 10 is 2.5 mm, and the aperture of the sliding bearing 11 is mm, so that the fitting clearance between the left part of the impeller shaft 10 (ie, the journal) and the shaft hole of the sliding bearing 11 is maintained between 2 μm and 7 μm.

[0039] When in use, after starting the motor 1, air is sucked in from the air inlet on the upper part of the housing assembly 3, and after the blades 6 on the impeller work twice, it is blown out from the air outlet on the side (i.e., the front lower part) of the housing assembly 3.

[0040] The novel low-noise crossflow fan of the present invention is suitable for crossflow fans with an impeller outer diameter of 30-60 mm, and is used in conjunction with household appliances such as refrigerators, display cabinets, air conditioners, heaters, electric fireplaces, air curtains, and built-in ovens.

Claims

1. A novel low-noise crossflow fan, comprising a motor (1), an impeller, an impeller shaft (10), a bearing assembly and a casing assembly (3); the bearing assembly comprises a sliding bearing seat (12) and a sliding bearing (11) embedded therein, the impeller shaft (10) is arranged in the middle of the left end of the impeller, the motor (1) and the bearing assembly are respectively arranged in the middle of the right part and the left end of the casing assembly (3); the impeller is arranged in the casing assembly (3), the impeller shaft (10) at the left end thereof is inserted into the sliding bearing (11) of the bearing assembly, and the right end thereof is connected to the motor output shaft (2) of the motor (1); the characteristics are: The diameter of the left part of the impeller shaft (10) inserted into the sliding bearing (11) is 2.0-3.5 mm, the hole diameter of the sliding bearing (11) is 2.0-3.5 mm, and the matching clearance between the two is 2 μm to 7 μm.

2. The novel low noise cross flow fan according to claim 1 is characterized in that: The diameter of the left portion of the impeller shaft (10) is 2.0-3.0 mm, the aperture of the sliding bearing (11) is 2.0-3.0 mm, and the matching clearance between the two is 2 μm to 7 μm.

3. The novel low noise cross flow fan according to claim 2 is characterized in that: The diameter of the left portion of the impeller shaft (10) is 2.5 mm, the aperture of the sliding bearing (11) is 2.5 mm, and the matching clearance between the two is 2 μm to 7 μm.

4. The novel low noise cross flow fan according to any one of claims 1 to 3, characterized in that: The impeller comprises an impeller left disc (8), an impeller middle disc (7), an impeller right disc (5), an impeller shaft sleeve (9), a coupling (4), an impeller shaft (10) and more than two blades (6); the blades (6) are sequentially inserted into blade grooves around the impeller left disc (8), the impeller middle disc (7) and the impeller right disc (5); the impeller shaft sleeve (9) and the coupling (4) which are mounted with the impeller shaft (10) are respectively arranged in the middle of the impeller left disc (8) and the impeller right disc (5); and the left end of the motor output shaft (2) is connected to the coupling (4).

5. The novel low noise cross flow fan according to claim 4 is characterized in that: The blade (6) is arc-shaped, and its outer circumference angle β is 60-90°.

6. The novel low noise cross flow fan according to claim 5 is characterized in that: The outer circumference angle β of the blade (6) is 78°.

7. The novel low noise cross flow fan according to claim 4 is characterized in that: The diameter ratio D1 / D2 of the impeller is 0.68-0.85, and the relative pitch t / c of ​​the impeller is 0.87-1.

13.

8. The novel low noise cross flow fan according to claim 7 is characterized in that: The diameter ratio D1 / D2 of the impeller is 0.728, and the relative pitch t / c of ​​the impeller is 1.

0.

9. The novel low noise cross flow fan according to claim 7 is characterized in that: The impeller blades (6) are relative to the impeller center disk (7), and the angle γ between the blade chord length direction and the line connecting the intersection of the blade inner circle and the center of the impeller center disk (7) is 20-35 degrees.

10. The novel low noise cross flow fan according to claim 9 is characterized in that: The angle γ of the blade chord length direction relative to the line connecting the intersection of the blade inner circle and the center of the impeller center disk (7) is 31°.

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