Centrifugal fan

Abstract

The present invention relates to a centrifugal fan capable of minimizing impact applied to an upper bearing during a drop impact by floating the upper bearing. According to the present invention, the centrifugal fan comprises: a fan cover; a lower case to which a lower end portion of the fan cover is coupled and fixed and which has a bearing housing protruding from a central portion thereof; upper and lower bearings inserted into a hollow portion of the bearing housing; a rotary shaft rotatably supported by the upper and lower bearings; a rotor in which an uppermost part of the rotary shaft is coupled and fixed to a shaft support portion of a rotor support body; a stator for rotating the rotor; an impeller rotating inside the fan cover together with the rotor; a first spring inserted between the shaft support portion and the upper bearing to elastically support the rotor; and a second spring inserted between the upper bearing and a first stepped portion to elastically support the upper bearing.

Description

centrifugal fan

[0001] The present invention relates to a centrifugal fan, and more particularly, to a centrifugal fan capable of minimizing the impact applied to an upper bearing when subjected to a falling impact by inserting first and second springs into the upper and lower portions of the upper bearing to float the upper bearing.

[0002] In general, blower fans used in various industrial machines, air conditioning devices, etc. can be classified into axial fans (FAN) that are used primarily for air volume, transverse fans (FAN) that provide uniform airflow, and centrifugal fans (FAN) that are used primarily for static pressure.

[0003] The above axial fan (FAN) is a fan that generates wind in the direction of the rotation axis by pressurizing air with a propeller (PROPELLER) located in a circular path between a cylindrical hub (HUB) and casting (CASTING), and has a compact structure in which the wind flow follows the rotation axis, and can also obtain a large wind volume, making it suitable for ventilation cooling purposes that cool the entire inside of a device.

[0004] The above crossflow fan has a runner similar to a centrifugal fan, but since both sides are covered with side plates, there is no inflow of gas from the axial direction, and instead, a flow occurs through the runner. In addition, since the air is blown using a long cylindrical runner, the width of the wind can be wide, so the wind is discharged horizontally along the circumference of the runner, making the wind uniform.

[0005] The centrifugal fan above creates a rotational flow almost perpendicular to the rotation axis by the centrifugal force of a cylindrically arranged runner, and the generated rotational flow is rectified in one direction by a scroll, and the pressure also increases, and the discharge port is tightened to concentrate the wind in a certain direction, so it is used for local cooling, and is also suitable for cooling equipment with poor ventilation due to high static pressure or for ventilation using a duct.

[0006] The centrifugal fan has the highest air volume per unit area in the medium pressure range and can be used for various purposes due to its low noise and quiet operation. It includes an impeller within a motor-driven hub that draws air into the housing and then discharges the air through an outlet perpendicular (90 degrees) to the intake.

[0007] A typical axial fan features multiple blades mounted on a rotating shaft (or axle) driven by a motor, drawing air in from one end and exhausting it out the other, parallel to the shaft. Accordingly, axial fans use a single sleeve bearing to support the rotating shaft formed by the impeller, which is integrally formed with the rotor.

[0008] A fan motor equipped with a flow prevention spring to prevent noise or vibration by minimizing the flow of the rotating shaft caused by the micro-gap between the outer surface of the sleeve bearing and the rotating shaft in the above-described axial fan is disclosed in Korean Patent Publication No. 10-2117786 (Patent Document 1). In the case of having a sleeve bearing as in Patent Document 1, when applied as a headlamp cooling fan, there is a problem that the lifespan is shortened because it can be used in a high-temperature environment of 105℃ or higher, causing oil leakage.

[0009] In addition, in a blower fan having an impeller with a plurality of blades formed radially around a fan housing, upper and lower bearings are installed at the upper and lower portions of a rotational shaft to rotatably support the rotational shaft, but a technology for providing elasticity in the up-and-down direction so that the rotational body can rotate smoothly by automatically adjusting the stroke between the upper and lower bearings by providing a ring-shaped spring between the lower bearing and the base bracket is disclosed in Korean Patent Publication No. 10-1309689 (Patent Document 2).

[0010] The sirocco fan, a type of centrifugal fan, has a large impeller that is assembled integrally with the rotor, so it supports a large load by using upper and lower bearings positioned at the top and bottom of the rotation shaft, and uses ball bearings to ensure low noise and long life durability.

[0011] However, when a conventional sirocco fan supports a rotating shaft by two ball bearings consisting of an upper and lower bearing, if a spring for reducing preload is not used, the load of the impeller of the upper bearing, which comes into contact with the lower part of the impeller during an upper and lower impact, may be transmitted to the inner ring, causing the rotating shaft to shake.

[0012] To suppress the occurrence of such shaking of the rotating shaft, a spring is conventionally installed between the lower part of the bearing housing and the upper part of the lower bearing or between the lower part of the impeller and the upper part of the upper bearing to reduce the preload applied to the bearing.

[0013] In this case, the sirocco fan has a structure in which the load of the large impeller applies a large preload to the upper bearing, so a countermeasure is required to reduce the preload on the upper bearing in particular.

[0014] Korean Patent Laid-Open Publication No. 10-2022-0125609 (Patent Document 1) discloses a fan motor in which a rotary shaft having a front end embedded in a disk-shaped base is supported by the outer rings of upper and lower bearings on the upper and lower sides of a guide, respectively, and the inner ring is supported by a pair of ball bearings installed on the rotary shaft, a first spring is installed between a first bearing and a disk-shaped base, and a second spring is installed between the inner rings of the upper and lower bearings, so that the second spring elastically supports the upper and lower bearings in a direction opposite to the direction in which the upper and lower bearings are pressed by the first spring.

[0015] As in Patent Document 1, a second spring is installed between the inner rings of the upper and lower bearings, and the contact point of the second spring supports only the inner rings of the upper and lower bearings, so the forces applied to the upper and lower bearings are elastically balanced.

[0016] As a result, in the fan motor of Patent Document 1, the first spring applies pressure to the inner ring of the impeller and the upper bearing, so that the rotation shaft and the inner ring of the upper bearing rotate together when the impeller rotates, and the second spring applies pressure to the inner ring of the upper bearing and the inner ring of the lower bearing, but when the impeller rotates, the inner ring of the upper bearing and the inner ring of the lower bearing also rotate together with the rotation shaft.

[0017] Accordingly, in the fan motor of Patent Document 1, the second spring has a weak preload applied to the inner ring of the upper bearing and the inner ring of the lower bearing, and the first and second springs are not fixed, so noise may be generated due to a slip phenomenon. In addition, the outer ring of the upper bearing and the outer ring of the lower bearing are also weakly fixed, so noise may be generated due to a slip phenomenon.

[0018] Additionally, in conventional fan motors, the magnets forming the rotor and the back yoke forming the magnetic circuit are generally installed in layers inside the rotor support with the same size.

[0019] Accordingly, the present invention has been proposed to solve the problems of the above-mentioned prior art, and its purpose is to provide a centrifugal fan in which the impact applied to the upper bearing when dropped is minimized by inserting first and second springs into the upper and lower portions of the upper bearing to float the upper bearing, thereby enabling the inner ring of the upper bearing to rotate smoothly along with the rotational axis when the rotor and impeller rotate, and the outer ring of the upper bearing is fixed by the second spring, thereby suppressing noise generation due to the slip phenomenon of the second spring.

[0020] Another object of the present invention is to provide a centrifugal fan capable of minimizing electromagnetic waves emitted from the fan and reducing the weight and thickness of the rotor support by forming one side of the back yoke to be extended close to the rotation axis, thereby serving as a magnetic circuit for the magnet of the rotor.

[0021] In order to achieve the above object, a centrifugal fan according to one feature of the present invention comprises: a fan cover having an air inlet formed in the center of the upper portion through which air is introduced, and an air outlet formed on the side through which air is discharged; a lower case having a bearing housing having a lower portion of the fan cover fixedly coupled to an upper surface of an outer circumference thereof and having first and second stepped portions formed inside a hollow portion in the center thereof, the lower portion of the fan cover protrudingly formed; upper and lower bearings each formed of a ball bearing having a ball inserted between an inner ring and an outer ring, the upper and lower bearings being inserted into the hollow portions of the bearing housings; a rotating shaft having an upper portion and a lower portion rotatably supported by the upper and lower bearings, respectively; a rotor having an uppermost portion of the rotating shaft fixedly coupled to an axial support portion of a rotor support; a stator fixed to an outer circumference of the bearing housing and positioned with a predetermined air gap between the rotor to rotate the rotor; an impeller integrally formed with the rotor at a gap from the outer circumference of the rotor to rotate within the fan cover together with the rotor; a first spring inserted between the axial support portion of the rotor support and the inner ring of the upper bearing to elastically support the rotor; And it is characterized by including a second spring inserted between the outer ring of the upper bearing and the first step portion to elastically support the outer ring of the upper bearing.

[0022] The above first spring may be set to have a relatively smaller preload than the second spring.

[0023] In addition, the upper and lower bearings each include an inner ring that is fixedly joined to the outer periphery of the rotation shaft and rotates together with the rotation shaft; an outer ring that is press-fitted and fixed into the hollow portion of the bearing housing; and a plurality of balls inserted between the inner ring and the outer ring; and the second spring is installed to apply pressure to the outer ring of the upper bearing and the inner side of the first step portion of the bearing housing, so that when the rotor rotates, the inner ring of the upper bearing can rotate, but the outer ring can remain fixed.

[0024] Moreover, the rotor comprises a magnet which is arranged on the outer surface of the stator with a certain gap and is formed in a cylindrical shape and has a structure in which N and S poles are alternately arranged or N and S poles are alternately split-magnetized; a back yoke which is arranged on the outer surface of the magnet to form a magnetic circuit; and a rotor support body in which the magnet and the back yoke are fixed and the impeller is integrally formed; wherein the back yoke is formed in an inverted cup shape extending from a magnetic circuit forming portion surrounding the magnet so that the other side approaches the rotation axis, and can serve as a magnetic circuit for the magnet of the rotor and absorb leakage electromagnetic waves emitted from the centrifugal fan while reinforcing the strength of the rotor support body.

[0025] In this case, the back yoke may include a magnetic circuit forming portion facing the magnet; a vertical extension portion that is bent once along the upper end of the magnet from the magnetic circuit forming portion and then bent again to extend upward from the bent portion; and a disc portion that is bent 90 degrees from the upper end of the vertical extension portion to form a disc shape.

[0026] In addition, the rotor support may be formed such that a rotation axis is connected to a shaft support extending downwardly from the center of the upper plate in the shape of a disk, and extends downwardly along the back yoke so as to surround the back yoke from the outer periphery of the upper plate.

[0027] Furthermore, a plurality of through holes are perforated at intervals in the center and outer periphery of the above-mentioned disc portion, and the rotor support and the shaft support, which are respectively arranged on the upper and lower portions of the above-mentioned disc portion, can be integrated through the plurality of through holes.

[0028] A centrifugal fan according to the present invention further includes a printed circuit board (PCB) mounted on a lower side of the stator and having various circuit components of a motor drive circuit mounted thereon to supply a motor drive signal to the stator, wherein the stator includes: a stator core having an inner circumference of a back yoke fixed to an outer circumference of the bearing housing and having a plurality of teeth extending therefrom on which coils are wound; a bobbin having a plurality of protrusions surrounding the plurality of teeth of the stator core and the back yoke and having a through hole formed in the center between the plurality of teeth; a coil wound in a coil winding region of the bobbin and to which the motor drive signal is applied; and a pair of connecting pins each inserted into the through hole of the protrusion and electrically connecting a start terminal and an end terminal of the coil and the printed circuit board (PCB); wherein the rotor and the stator can form a fan motor driven in a single-phase drive manner.

[0029] The above centrifugal fan may have a sirocco fan structure.

[0030] As described above, conventionally, a structure has been proposed that makes it difficult to reduce a large preload applied to the upper bearing by the load of a large impeller and rotor by arranging springs only on the upper part of the upper bearing or only on the upper part of the lower bearing, but in the present invention, the first spring supports the inner ring of the upper bearing, and the second spring supports the outer ring of the upper bearing. As a result, when the rotor and impeller rotate, the inner ring of the upper bearing can rotate smoothly together with the rotational axis, and the outer ring of the upper bearing is fixed by the second spring, so that noise generation due to a slip phenomenon of the second spring can be suppressed.

[0031] In the present invention, the impact applied to the upper bearing when subjected to a falling impact can be minimized by inserting the first and second springs into the upper and lower portions of the upper bearing to make the upper bearing float.

[0032] In addition, the present invention employs a centrifugal blower that satisfies low speed, low pressure, and high air volume to reduce noise and power consumption, for example, a multi-blade blower having a sirocco fan structure, thereby increasing the suction volume while lowering the fan driving speed, thereby enabling it to be effectively used for cooling a vehicle headlamp used in a limited space of 100°C or higher.

[0033] Moreover, in the present invention, by extending one side of the back yoke of the rotor so as to be close to the rotation axis, it is possible to minimize electromagnetic waves emitted from the centrifugal fan while also serving as a magnetic circuit for the magnet of the rotor, and to achieve weight reduction and thinning of the rotor support.

[0034] FIGS. 1A to 1C are a plan perspective view, a top view, and a rear view, respectively, showing a centrifugal fan according to a preferred embodiment of the present invention.

[0035] Figures 2 and 3 are cross-sectional views taken along line AA of Figure 1b and line BB of Figure 1c, respectively.

[0036] FIGS. 4A to 4D are a plan perspective view, a bottom perspective view, an axial cross-sectional view, and a diametrical cross-sectional view, respectively, showing a fan motor used in a centrifugal fan according to a preferred embodiment of the present invention.

[0037] FIGS. 5A and 5B are a perspective view and an axial cross-sectional view, respectively, showing a state in which a printed circuit board (PCB) and a connector are coupled to a fan motor according to a preferred embodiment of the present invention.

[0038] Figure 6 is a fully exploded perspective view of a centrifugal fan according to a preferred embodiment of the present invention.

[0039] Figure 7 is an exploded perspective view of a centrifugal fan module according to a preferred embodiment of the present invention.

[0040] Fig. 8 is an enlarged cross-sectional view showing the rotation shaft and bearing portion of a centrifugal fan according to the present invention.

[0041] Hereinafter, a preferred embodiment according to the present invention will be described with reference to the attached drawings.

[0042] In this process, the sizes and shapes of components depicted in the drawings may be exaggerated for clarity and convenience. Furthermore, terms specifically defined in consideration of the structure and operation of the present invention may vary depending on the intent or custom of the user or operator. Definitions of these terms should be based on the content throughout this specification.

[0043] The centrifugal fan according to the present invention includes an impeller within a motor-driven hub that draws in outside air from an air intake in the center of the housing and then discharges the air through an exhaust port perpendicular (90 degrees) to the air intake port, and has the largest air volume per unit area and can be used for various purposes due to its low noise and quiet operation.

[0044] The sirocco fan, a type of centrifugal fan according to the present invention, is a multi-blade fan with a large volume of impeller (runner) assembled integrally with the rotor, and thus supports a large load by using upper and lower bearings positioned at the upper and lower portions of the rotation shaft, and applies ball bearings in consideration of low noise, long life, and durability.

[0045] The centrifugal fan according to the present invention creates a rotational flow almost perpendicular to the rotation axis by the centrifugal force of the impeller arranged in a cylindrical shape, and the generated rotational flow is rectified in one direction by the scroll, and the pressure is also increased, and the discharge port is tightened to concentrate the wind in a certain direction, so it is used for local cooling, and is also suitable for cooling equipment that does not pass wind well due to high static pressure or for blowing air using a duct.

[0046] Referring to FIGS. 1A to 7, a centrifugal fan (100) according to one embodiment of the present invention comprises: a fan cover (10) having an air inlet (11) formed in the center of the upper portion through which air is introduced, and an air outlet (12) formed on the side through which air is discharged; a lower case (20) in which the lower portion of the fan cover (10) is fixedly coupled to the upper surface of the outer circumference and a bearing housing (61) protruding from the center portion is integrally formed; upper and lower bearings (62, 63) inserted into the hollow portion (61d) of the bearing housing (61); a rotational shaft (60) in which the upper and lower portions are rotatably supported by the upper and lower bearings (62, 63), respectively; a rotor (30) in which a rotor support (33) is fixed to the uppermost portion of the rotational shaft (60); a stator (40) fixed to the outer circumference of the bearing housing (61) and arranged with a predetermined air gap from the rotor (30); and a rotor (30) It includes an impeller (20) that is formed integrally on the outer periphery and rotates inside the fan cover (10) together with the rotor (30), and a printed circuit board (PCB) (50) that is fixed to the upper portion of the lower case (20) and is positioned on the lower side of the stator (40) so as to supply a motor drive signal to the stator (40) and on which various circuit components of the motor drive circuit are mounted.

[0047] The centrifugal fan (100) above creates a rotational flow in a direction almost perpendicular to the rotation axis (60) by the centrifugal force of the cylindrical impeller (70), and the generated rotational flow is rectified in one direction by the impeller (70), the pressure also increases, and the air outlet (12) is tightened to concentrate the wind in a certain direction.

[0048] To this end, the fan cover (10) and the lower case (20) have an external shape in the form of a logarithmic spiral or an Archimedean spiral, as shown in Fig. 1a, and the four sides of the outlet are formed in a flat shape to form a rectangular air outlet (12).

[0049] As a result, the inner surface formed by the combination of the fan cover (10) and the lower case (20) has a curved surface in the shape of a logarithmic spiral or an Archimedean spiral, and a vortex chamber (16) that guides and swirls air in the circumferential direction is formed between the impeller (70) and the inner surface of the fan cover (10).

[0050] The above fan cover (10) is composed of a top plate (15a) having an air inlet (11) formed in the center through which air is introduced, and a side portion (15b) extending perpendicularly to the outer periphery of the top plate (15a) to form an air outlet (12) through which air is discharged on one side.

[0051] The side surface (15b) of the fan cover (10) has a plurality of connecting holes (13) formed through the lower portion, and a plurality of fixing protrusions (25) that are snap-coupled to the plurality of connecting holes (13) protrude from the outer periphery of the lower case (20). Accordingly, when assembling the fan cover (10) to the lower case (20), the plurality of fixing protrusions (25) are snap-coupled to the plurality of connecting holes (13) to thereby secure the fan cover.

[0052] On the side of the fan cover (10) and the lower case (20), a plurality of protrusions (14) (24) are formed with through holes for fastening fixing screws or bolts to fix the centrifugal fan (100) to the main body.

[0053] A joining groove (23) is formed on the side of the lower case (20) to which a connector (55) is joined, and when the connector (55) is inserted into the joining groove (23), it can be fixed by snap-joining with the lower case (20).

[0054] In addition, various circuit components (52) of a motor drive circuit that controls a centrifugal fan (100) are mounted on the upper part of the lower case (20), and a printed circuit board (PCB; 50) that is electrically connected to the motor drive circuit through two connection pins (46) from the coil (44) of the stator (40) is installed.

[0055] The above connector (55) is fixed by snap-fitting to the lower case (20), and then electrically connected to a printed circuit board (PCB; 50) through a plurality of pin terminals (53). In this case, the plurality of pin terminals (53) may be configured as, for example, four, and Vcc, GND, PWM control signals, and FG signals may be transmitted.

[0056] The upper surface of the lower case (20) is divided into a central area (26) where a circular printed circuit board (PCB; 50) having a through hole (50a) formed in the center is placed, and a vortex area (21) that forms the bottom of a vortex chamber (16) through which vortex air passes.

[0057] In this case, a plurality of guide protrusions (27) are protruded from the outer surface of the central area (26) of the lower case (20) to support and leave a space between the printed circuit board (PCB; 50) and the lower case (20).

[0058] In the center of the lower case (20), a bearing housing (61) having a hollow portion (61d) inside is integrally formed to protrude, and upper and lower bearings (62, 63) are inserted into the hollow portion (61d).

[0059] The upper and lower bearings (62, 63) that are coupled to the upper and lower portions of the above-described rotary shaft (60) and rotatably support the rotary shaft (60) are each made of ball bearings. In this case, the inner rings (62a, 63a) of the upper and lower bearings (62, 63) are fixedly installed to the upper and lower portions of the rotary shaft (60), respectively, and the outer rings (62b, 63b) are supported by first and second stepped portions (61a, 61b) formed inside the hollow portion (61d) after the outer periphery is press-fitted into the hollow portion (61d) of the bearing housing (61).

[0060] The lower part of the above-mentioned rotary shaft (60) has an annular coupling groove formed therein, and a slit washer (64) is coupled to the coupling groove to prevent the rotary shaft (60) from being separated from the lower bearing (63) due to the lifting force generated when the impeller (70) rotates.

[0061] The upper part of the above rotation shaft (60) is embedded in the shaft support (34) of the rotor support (33) and connected to the rotor (30).

[0062] In the centrifugal fan (100) according to the present invention, the fan motor (150) that drives the impeller (70) to rotate can be configured as a BLDC motor with an outer rotor structure of a radial gap type, and the drive control can be performed, for example, in a single-phase drive method or a three-phase drive method.

[0063] The fan motor (150) of the illustrated embodiment is exemplified as having a 4-slot-4-pole structure with a single-phase drive method, but the present invention is not limited thereto and may be configured in various ways.

[0064] The rotor (30) is formed in a cylindrical shape and is arranged with a certain gap on the outer surface of the stator (40), and includes a magnet (31) having a structure in which N and S poles are alternately arranged or N and S poles are alternately divided and magnetized, a back yoke (32) arranged on the outer surface of the magnet (31) to form a magnetic circuit, and a rotor support (33) to which the magnet (31) and the back yoke (32) are fixed and an impeller (70) is integrally formed.

[0065] The above back yoke (32) includes a magnetic circuit forming portion (32a) facing the magnet (31), a vertical extension portion (32c) that is bent once along the upper end of the magnet (31) from the magnetic circuit forming portion (32a) and then bent again to extend upward from the bend portion (32b), and a circular portion (32d) that is bent 90 degrees from the upper end of the vertical extension portion (32c) to form a circular shape.

[0066] A plurality of through holes (32f, 32e) are perforated at intervals in the center and outer periphery of the above-mentioned disc portion (32d), and these plurality of through holes (32f, 32e) enable the rotor support (33) and the shaft support (34) respectively disposed at the upper and lower portions of the above-mentioned disc portion (32d) to be integrated. That is, the rotor support (33), the shaft support (34), and the rotational shaft (60) can be integrally formed by an insert molding method using BMC.

[0067] The above back yoke (32) is formed by extending from the magnetic circuit forming portion (32a) in an inverted cup shape so that the other side approaches the rotation axis (60), thereby acting as a magnetic circuit for the magnet (31) of the rotor (30) and absorbing electromagnetic waves emitted from the centrifugal fan (100), thereby minimizing leakage electromagnetic waves and promoting weight reduction and thinning of the rotor support (33).

[0068] The above rotor support (33) has a rotating shaft (60) connected to a shaft support (34) extending downward from the center of the upper plate in the shape of a disk, and is formed to extend downward along the back yoke (32) so as to surround the back yoke (32) from the outer periphery of the upper plate.

[0069] The impeller (70) is connected at the lower end through an annular lower connection portion (35) extending radially from the lower end of the rotor support (33), and a plurality of blades (72) are arranged vertically upward from the outer circumference of the lower connection portion (35) at a predetermined angle of inclination at a constant interval, and the upper portions of the plurality of blades (72) are interconnected by an annular ring (71).

[0070] Accordingly, the impeller (70) is formed in an overall cylindrical shape and is vertically arranged with a gap around the rotor (30) to surround the rotor (30), and when the rotor (30) rotates, the impeller (70) also rotates and creates a rotational flow in a direction almost perpendicular to the rotational axis (60) by the centrifugal force of the impeller (70) due to the inclination angle of the plurality of blades (72), and the generated rotational flow is rectified in one direction by a scroll casing formed by a fan cover (10) and a lower case (20) and having a spiral shape, and the pressure also increases and is discharged through the air discharge port (12).

[0071] The rotary shaft (60) formed integrally in the center of the rotor support (33) by insert injection has a plurality of annular grooves to prevent separation while increasing the mutual coupling area with the rotor support (33).

[0072] The above stator (40) is press-fitted into the outer circumference of the bearing housing (61) and supported by a stepped portion (61c) formed on the outer circumference of the bearing housing (61).

[0073] The above stator (40), as shown in FIGS. 4a to 5b, includes a stator core (45), a bobbin (43) surrounding the coil winding area of ​​the stator core (45) and the back yoke (42), and a coil (44) wound on the coil winding area of ​​the bobbin (43) and to which a motor driving signal is applied.

[0074] The above stator core (45) includes a plurality of teeth (41) formed in a 'T' shape and extending radially to form a coil winding area on the outer side of the annular yoke (42) and an annular yoke (42).

[0075] In this case, a plurality of protrusions (45) are protruded between the teeth on the bobbin (43) surrounding the outer side of the annular yoke (42), and two connecting pins (46) and one support pin are press-fitted into a through hole (47a) formed in the center of the protrusions (47), and an electrical / physical connection is made with the PCB (50) arranged on the lower side of the stator (40) using the two connecting pins (46) to connect the coil (44) of the stator (40) and the PCB (50).

[0076] The above stator (40) has a 4-slot structure as it is driven in a single phase driving method suitable for a small motor, for example, and one end of two connecting pins (46) is connected to the start terminal and the end terminal of one coil (44) wound on a bobbin (43), and the lower end of the connecting pin (46) is connected to a PCB (50) equipped with a motor driving circuit so that a motor driving signal can be transmitted from the PCB (50).

[0077] Referring to FIG. 2, FIG. 4c and FIG. 8, the centrifugal fan (100) according to the present invention has upper and lower bearings (62, 63) coupled to the upper and lower portions of the rotation shaft (60) so as to rotatably support the rotation shaft (60).

[0078] The upper and lower bearings (62, 63) are inserted into and fixed in the hollow portion (61d) of the bearing housing (61).

[0079] The upper and lower bearings (62, 63) are each made of ball bearings and have a structure in which a plurality of balls (62c, 63c) are inserted between an inner ring (62a, 63a) that is fixedly joined to the outer periphery of the rotation shaft (60) and rotates together with the rotation shaft (60) and an outer ring (62b, 63b) that is press-fitted and fixed into the hollow portion (61d) of the bearing housing (61).

[0080] The hollow portion (61d) of the above bearing housing (61) has first and second stepped portions (61a, 61b) for supporting a spring and a bearing therein. In this case, the upper bearing (62) is assembled on the upper portion of the first stepped portion (61a), and the lower bearing (63) has its outer ring (63b) supported on the second stepped portion (61b).

[0081] In the present invention, a first spring (81) is inserted between the shaft support part (34) of the rotor (30) and the inner ring (62a) of the upper bearing (62) to protect the impact applied to the upper and lower bearings (62, 63) when the centrifugal fan (100) is dropped, and to absorb noise and vibration when the rotor (30) and the rotation shaft (60) rotate, and a second spring (82) is inserted between the outer ring (62b) of the upper bearing (62) and the first step part (61a).

[0082] Accordingly, the first spring (81) applies the same preload to the shaft support (34) and the upper bearing (62) of the rotor (30), respectively, and the second spring (82) acts to apply the same preload to the upper bearing (62) and the lower bearing (63).

[0083] In this case, the first spring (81) may be set to have a relatively smaller preload than the second spring (82). For example, the first spring (81) may be configured to have a preload of 120 g, and the second spring (82) may be configured to have a preload of 150 g.

[0084] When the preload of the first spring (81) and the second spring (82) is set in this way, the preload of 120g of the first spring (81) and the preload of 150g of the second spring (82) are offset, and the preload applied to the upper bearing (62) is greatly reduced to 30g, so that even if an impact is applied by the combined large load of the rotor (30) and the impeller (70) during a drop test of the centrifugal fan (100), the upper bearing (62) is elastically supported in a floating state by the first spring (81) and the second spring (82) at the upper and lower portions, so that the impact applied to the upper bearing (62) during the drop impact can be minimized.

[0085] In addition, the first spring (81) applies pressure to the shaft support (34) and the upper bearing (62) of the rotor (30), respectively, so that the rotation shaft (60) and the inner ring (62a) of the upper bearing (62) can rotate together when the rotor (30) and the impeller (70) rotate, and the second spring (82) is fixedly installed so as to apply pressure to the outer ring (62b) of the upper bearing (62) and the inner side of the first step (61a) of the bearing housing (61), so that the outer ring (62b) of the upper bearing (62) is fixed so as not to rotate when the rotor (30) and the impeller (70) rotate.

[0086] As a result, when the rotor (30) and impeller (70) rotate, the inner ring (62a) of the upper bearing (62) rotates, but the outer ring (62b) remains fixed.

[0087] Accordingly, the rotation shaft (60) and the inner ring (62a) of the upper bearing (62) rotate smoothly in accordance with the rotation of the rotor (30) and the impeller (70), and the second spring (82) is maintained in a fixed state, so that the slip phenomenon of the second spring (82) does not occur, which is advantageous for noise suppression.

[0088]

[0089] (Noise measurement test after drop test)

[0090] Below, a drop test was performed on the samples of Comparative Examples 1 and 2 and the present invention, and the noise value (dB) was measured, and the results are shown in Table 1 below.

[0091] The sample of Comparative Example 1 has a structure in which one spring is inserted between the outer ring of the lower bearing of a worm-core fan and the second step, and the sample of Comparative Example 2 has a structure in which one spring is inserted between the inner ring of the upper bearing of a worm-core fan and the shaft support of the rotor.

[0092] As shown in Fig. 9, a sample of the present invention uses a worm-core fan (100) in which a first spring (81) is inserted between the shaft support portion (34) of the rotor (30) and the inner ring (62a) of the upper bearing (62), and a second spring (82) is inserted between the outer ring (62b) of the upper bearing (62) and the first step portion (61a).

[0093] (Drop test method)

[0094] Each of the samples of Comparative Examples 1 and 2 and the present invention was freely dropped onto concrete from a height of 1 m. This was performed twice for each sample, and the second drop direction of the sample was opposite to the first drop direction.

[0095] (Noise value (dB) measurement method)

[0096] The noise values ​​(dB) of the samples of Comparative Examples 1 and 2 and the present invention were measured in an anechoic chamber with a dark noise level of 23 dB or less. After mounting the samples on a noise measurement jig specifically for centrifugal fans, noise was measured using a microphone at a point 1000 mm from the jig. The measurement direction was set horizontally from the tip of the microphone to the end of the fan housing. The direction of the sample's air outlet was set in the opposite direction of the microphone.

[0097] (Noise value (dB) measurement results)

[0098] Falling direction No. Comparative example 1 Comparative example 2 Invention prediction Upward drop 149.3 47.0 42.0 2 47.6 48.6 43.6 Side drop 146.7 44.0 45.7 2 47.5 46.2 44.7 Average value 47.8 46.5 44.0

[0099] As shown in Table 1 above, according to the results of the noise measurement test after the drop test, the inspection standard for the noise test value of the automobile manufacturer using the worm core fan is Max. 47.0 dB, so the sample of Comparative Example 1 did not satisfy the inspection standard, and the samples of Comparative Example 2 and the example of the present invention satisfied the inspection standard for the noise value, but it was found that the example of the present invention had a noise characteristic that was significantly lower than that of Comparative Example 2. As described above, the centrifugal fan according to the present invention minimizes the impact applied to the upper bearing when dropped by inserting the first and second springs at the upper and lower portions of the upper bearing to float the upper bearing, so that the inner ring of the upper bearing can rotate smoothly together with the rotation shaft when the rotor and impeller rotate, and the outer ring of the upper bearing is fixed by the second spring, so that noise generation due to the slip phenomenon of the second spring can be suppressed.

[0100] Although the present invention has been described and illustrated with specific preferred embodiments as examples, the present invention is not limited to the above embodiments, and various changes and modifications may be made by a person having ordinary skill in the art to which the invention pertains within a scope that does not depart from the spirit of the present invention.

[0101] The present invention is a centrifugal fan capable of minimizing the impact applied to the upper bearing when it is dropped by inserting first and second springs into the upper and lower portions of the upper bearing to float the upper bearing, and can be effectively used for cooling a vehicle headlamp.

Claims

1. A fan cover having an air inlet formed in the center of the upper part through which air flows in, and an air outlet formed on the side through which air is discharged; A lower case in which the lower part of the fan cover is fixedly joined to the upper surface of the outer periphery, and a bearing housing having first and second step portions protruding inside the hollow portion in the central portion is formed; Upper and lower bearings each consisting of a ball bearing inserted into the hollow portion of the bearing housing and having a ball inserted between the inner and outer rings; A rotary shaft, the upper and lower parts of which are rotatably supported on the upper and lower bearings, respectively; A rotor in which the uppermost part of the above-mentioned rotational axis is fixedly connected to the shaft support of the rotor support body; A stator fixed to the outer periphery of the bearing housing and positioned with a certain air gap between the rotor and the stator to rotate the rotor; An impeller formed integrally with the outer periphery of the rotor at intervals and rotated inside the fan cover together with the rotor; A first spring inserted between the shaft support of the rotor support body and the inner ring of the upper bearing to elastically support the rotor; and A centrifugal fan including a second spring inserted between the outer ring of the upper bearing and the first step portion to elastically support the outer ring of the upper bearing.

2. In paragraph 1, A centrifugal fan in which the first spring is set to have a relatively smaller preload than the second spring.

3. In paragraph 1, The upper and lower bearings are respectively An inner ring fixedly joined to the outer periphery of the above-mentioned rotary shaft and rotated together with the above-mentioned rotary shaft; An outer ring press-fitted into the hollow portion of the bearing housing; and It includes a plurality of balls inserted between the inner and outer rings; A centrifugal fan in which the second spring is installed to apply pressure to the outer ring of the upper bearing and the inner side of the first step of the bearing housing, so that when the rotor rotates, the inner ring of the upper bearing rotates, but the outer ring remains fixed.

4. In paragraph 1 The above rotor A magnet having a structure in which the N pole and the S pole are alternately arranged or the N pole and the S pole are alternately divided and magnetized, and is formed in a cylindrical shape with a certain gap placed on the outer surface of the stator; A back yoke arranged on the outer surface of the magnet to form a magnetic circuit; and A rotor support body in which the magnet and back yoke are fixed and the impeller is formed integrally; The above back yoke is formed in an inverted cup shape extending from a magnetic circuit forming part surrounding the magnet so that the other side is closer to the rotation axis, and serves as a magnetic circuit for the magnet of the rotor, while absorbing leakage electromagnetic waves emitted from the centrifugal fan and reinforcing the strength of the rotor support.

5. In paragraph 4, The above white yoke A magnetic circuit forming portion facing the above magnet; A vertical extension portion that is bent once along the top of the magnet from the magnetic circuit forming portion and then bent again and extends upward from the bent portion; and A centrifugal fan including a disc portion formed into a disc shape by bending 90 degrees at the upper end of the vertical extension portion.

6. In paragraph 4, The above rotor support is a centrifugal fan in which a rotation axis is connected to a shaft support extending downwardly from the center of a disc-shaped upper plate, and is formed to extend downwardly along the back yoke so as to surround the back yoke from the outer periphery of the upper plate.

7. In paragraph 5, A centrifugal fan in which a plurality of through holes are perforated at intervals in the center and outer periphery of the above-mentioned disc portion, and a rotor support and a shaft support, which are respectively arranged on the upper and lower portions of the above-mentioned disc portion, are integrated through the plurality of through holes.

8. In paragraph 1, It further includes a printed circuit board (PCB) on which various circuit components of a motor drive circuit are mounted to supply a motor drive signal to the stator and are arranged on the lower side of the stator. The above stator A stator core having a plurality of teeth formed extending from the outer surface of the bearing housing and having the inner surface of the back yoke fixed thereto, and on which a coil is wound; A bobbin having a plurality of protrusions formed in the center between the plurality of teeth and the back yoke of the stator core, the protrusions having a through hole formed in the center between the plurality of teeth; A coil wound in the coil winding area of ​​the above bobbin and to which the motor driving signal is applied; and Each of the above-described connecting pins is inserted into a through-hole of the protrusion and electrically connects the start terminal and end terminal of the coil and the printed circuit board (PCB); A centrifugal fan in which the rotor and stator form a fan motor driven by a single-phase drive method.

9. In paragraph 1, The above centrifugal fan is a centrifugal fan having a sirocco fan structure.

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