Fan rotational balance adjustment method, and fan

Abstract

This fan rotational balance adjustment method is a method for using an unbalance measurement device that detects the rotation of a rotating body by means of a laser and measures the unbalance of the rotating body, and adjusting the rotational balance of a resin fan serving as the rotating body. In a rotation reference position detection step, the rotation reference position of a rotating fan is detected as a result of emitting receiving light from the laser of the unbalance measurement device. In an unbalance measurement step, the phase angle of the eccentric position of the fan from the rotation reference position and the unbalance amount are obtained as measurement results measured by the unbalance measurement device. In an unbalance adjustment step, the unbalance amount is, in light of the measurement results, adjusted so as to be reduced by adding mass to a portion of the fan or by removing a portion of the fan. The fan has, as a reference display section indicating the rotation reference position, a first region that is on the surface of the fan and that is different from a second region which is not the reference display section. The reflectance of the laser in the first region is different from the reflectance of the laser in the second region.

Description

Method for Adjusting Rotational Balance of Fan and Fan

[0001] The present disclosure relates to a method for adjusting the rotational balance of a fan and a fan.

[0002] Patent Document 1 discloses a method for adjusting the dynamic balance of a rotating body when the rotating body rotates. In this method for adjusting dynamic balance, the rotating body is rotated, and the position in the rotational direction of the rotating body where the imbalance of the rotating body needs to be adjusted and the amount of the adhering material required to adjust the imbalance of the rotating body are measured. Next, based on the position regarding the imbalance of the rotating body and the measurement result of the amount of the adhering material, the adhering material is ejected and adhered non-contact from the adhering material delivery unit to the position where the imbalance of the rotating body is adjusted. Specifically, the rotating body is the rotating drum of a rotary magnetic head device or the rotor part of a motor that rotates the rotating drum relative to a fixed drum. The adhering material is solder.

[0003] In this method for adjusting dynamic balance, an imbalance measuring machine is used. The imbalance measuring machine measures the phase (position) in the rotational direction regarding the imbalance of each rotating body to be measured and the amount of solder, which is the adhering material required to adjust the imbalance. Patent Document 1 does not specifically describe the measurement of the phase (position) of the rotating body.

[0004] Patent Document 2 discloses a method for forming a rotational reference mark in a rotational balancing device. As its background art, it is disclosed that the rotational reference mark previously applied to the workpiece was obtained by coloring with oil-based ink or the like, which requires manual work and impairs productivity. Patent Document 3 discloses a method and a measuring device for measuring the mass imbalance of a rotating body, in which a sensor using a visible light semiconductor laser is used as a rotation sensor for detecting the rotational position of the rotating body non-contact.

[0005] When adjusting the rotational balance of a rotating body, if an unbalance measuring device is used that detects the rotation of the rotating body using a laser to measure its unbalance, the reference indicator section that shows the rotational reference position does not require coloring, but it does require some kind of change in the laser's light emission and reception. If work such as attaching a separate component after the rotating body is formed is performed to form the reference indicator section, the number of work steps increases, making it difficult to measure the unbalance.

[0006] Japanese Patent Publication No. 9-138901, Japanese Patent Publication No. 58-096232, Japanese Patent Publication No. 2008-180548

[0007] The purpose of this disclosure is to provide a fan rotation balance adjustment method and fan that facilitates the measurement and adjustment of unbalance using an unbalance measuring device.

[0008] A method for adjusting the rotational balance of a fan according to one aspect of the present disclosure is a method for adjusting the rotational balance of a resin fan, which is a rotating body, using an unbalance measuring device that detects the rotation of the rotating body with a laser and measures the unbalance of the rotating body. The rotational balance adjustment method comprises a rotation reference position detection step, an unbalance measurement step, and an unbalance adjustment step. The rotation reference position detection step is a step of detecting the rotation reference position of the rotating fan by transmitting and receiving light from the laser of the unbalance measuring device. The unbalance measurement step is a step of obtaining the phase angle of the eccentric position of the fan from the rotation reference position and the amount of unbalance as measurement results from the unbalance measuring device. The unbalance adjustment step is a step of adjusting the fan to reduce the amount of unbalance by adding mass to a part of the fan or removing a part of the fan, based on the measurement results. The fan has a first region on the surface of the fan that is different from a second region other than the reference display portion, as a reference display portion indicating the rotation reference position. The reflectivity of the laser in the first region is different from the reflectivity of the laser in the second region.

[0009] A method for adjusting the rotational balance of a fan according to another aspect of the present disclosure is a method for adjusting the rotational balance of a resin fan, which is a rotating body, using an unbalance measuring device that detects the rotation of the rotating body with a laser and measures the unbalance of the rotating body. The rotational balance adjustment method comprises a rotation reference position detection step, an unbalance measurement step, and an unbalance adjustment step. The rotation reference position detection step is a step of detecting the rotation reference position of the rotating fan by transmitting and receiving light from the laser of the unbalance measuring device. The unbalance measurement step is a step of obtaining the phase angle of the eccentric position of the fan from the rotation reference position and the amount of unbalance as measurement results from the unbalance measuring device. The unbalance adjustment step is a step of adjusting the fan to reduce the amount of unbalance by adding mass to a part of the fan or removing a part of the fan, based on the measurement results. The fan has a first region on the surface of the fan that is different from a second region other than the reference display portion, as a reference display portion indicating the rotation reference position. The first region protrudes from the second region.

[0010] A fan according to one aspect of the present disclosure is a resin fan whose rotational balance is adjusted by a method for adjusting the rotational balance of the fan. The fan has a bottom wall, a plurality of blades, a frame, and a balance adjustment section. The bottom wall has a bottom surface that intersects with the axis which is the rotation center of the fan. The plurality of blades are arranged around the axis and protrude from the bottom surface in a direction along the axis. The frame is annular in shape, connecting the plurality of blades at the ends of the plurality of blades opposite the bottom wall in the axial direction. The balance adjustment section is provided around the entire circumference of the axis, and mass is added or removed in the unbalance adjustment step.

[0011] The fan rotation balance adjustment method and fan according to this disclosure make it easier to measure and adjust the unbalance using an unbalance measuring device.

[0012] Figure 1 is a flowchart illustrating a method for adjusting the rotational balance of a fan according to an embodiment of this disclosure. Figure 2 is a plan view of a blower according to the first embodiment of this disclosure. Figure 3 is a longitudinal cross-sectional view of the same blower. Figure 4 is an exploded perspective view illustrating the assembly of the fan case of the same blower. Figure 5 is a schematic configuration diagram of a mobile body on which the same blower is installed. Figure 6 is an explanatory diagram of a rotation detection device in an unbalance measuring device. Figure 7 is a plan view of the centrifugal fan provided in the same blower. Figure 8 is a cross-sectional view of the main part of the same centrifugal fan. Figure 9 is a cross-sectional view of the main part of the centrifugal fan of the second embodiment. Figure 10 is a cross-sectional view of the main part of the centrifugal fan of the third embodiment. Figure 11 is a cross-sectional view of the main part of the centrifugal fan of the fourth embodiment. Figure 12 is a cross-sectional view of the main part of the centrifugal fan of the fifth embodiment. Figure 13 is a cross-sectional view of the main part of the centrifugal fan of the sixth embodiment. Figure 14 is a plan view of the centrifugal fan of the sixth embodiment. Figure 15 is a perspective view of the main part of the centrifugal fan of the sixth embodiment. Figure 16 is a cross-sectional view of the main part of the centrifugal fan according to the seventh embodiment.

[0013] The fan rotation balance adjustment method and fan according to this disclosure will be described below with reference to the drawings based on embodiments. The figures described in the following embodiments are schematic diagrams. The ratios of the size and thickness of each component do not necessarily reflect the actual dimensional ratios. The configuration described in the following embodiments is merely one example of this disclosure. This disclosure is not limited to the following embodiments, and various modifications are possible depending on the design, etc., as long as the effects of this disclosure can be achieved.

[0014] (Overview) Figure 1 is a flowchart showing a fan rotation balance adjustment method according to an embodiment of the present disclosure. Figure 7 is a plan view of a centrifugal fan 3 (fan) provided in a blower according to the first embodiment of the present disclosure. The fan rotation balance adjustment method according to an embodiment of the present disclosure is a method for adjusting the rotation balance of a resin fan (centrifugal fan 3) as a rotating body using an unbalance measuring device 4 (see Figure 6) that detects the rotation of a rotating body with a laser and measures the unbalance of the rotating body. As shown in Figure 1, the rotation balance adjustment method comprises a rotation reference position detection step (S10), an unbalance measurement step (S20), and an unbalance adjustment step (S30). The rotation reference position detection step (S10) is a step in which the rotation reference position of the rotating fan (centrifugal fan 3) is detected by the transmission and reception of light from the laser of the unbalance measuring device 4. The unbalance measurement step (S20) is a step in which the phase angle of the eccentric position of the fan (centrifugal fan 3) from the rotation reference position and the amount of unbalance are obtained as measurement results from the unbalance measuring device 4. The unbalance adjustment step (S30) is a step in which the amount of unbalance is reduced by adding mass to a part of the fan (centrifugal fan 3) or removing a part of the fan (centrifugal fan 3) based on the measurement results. As shown in Figure 7, the fan (centrifugal fan 3) has a first region 34 on the surface of the fan (centrifugal fan 3) that is different from the second region 35 other than the reference display portion 5, which serves as a reference display portion 5 that indicates the rotation reference position.

[0015] The reflectivity of the laser in the first region 34 is different from the reflectivity of the laser in the second region 35. Alternatively, the first region 34 protrudes from the surface of the second region 35.

[0016] The fan (centrifugal fan 3) according to this disclosure is a resin fan (centrifugal fan 3) whose rotational balance is adjusted by the rotational balance adjustment method for the fan (centrifugal fan 3) according to this disclosure. As shown in Figure 7, the fan (centrifugal fan 3) has a bottom wall 31, a plurality of blades 32, a frame 33, and a balance adjustment section 36. The bottom wall 31 has a bottom surface that intersects with the axis X1, which is the rotation center of the fan (centrifugal fan 3). The plurality of blades 32 are arranged around the axis X1 and protrude from the bottom surface in a direction that is along the axial direction A1 (upward in Figure 3). The frame 33 is annular in shape, connecting the plurality of blades 32 at the ends of the plurality of blades 32 opposite the bottom wall 31 in the axial direction A1. The balance adjustment section 36 is provided around the entire circumference of the axis X1, and mass is added or removed in the unbalance adjustment step.

[0017] The fan rotation balance adjustment method and fan according to this disclosure facilitate the measurement and adjustment of unbalance using an unbalance measuring device. In particular, when adjusting the unbalance, it is possible to correct the balance at the point furthest from the center of gravity (axis X1) of the fan (centrifugal fan 3). Therefore, unbalance adjustment is easy.

[0018] (First Embodiment) The method for adjusting the rotational balance of a fan and the fan according to the first embodiment will be described. First, the fan, which is a rotating body, will be described. The fan is a resin centrifugal fan 3 used in a blower.

[0019] (1) Basic configuration and operation of the blower The basic configuration and operation of the blower 1 will be explained using Figures 1 to 4. Figure 2 is a plan view of the blower 1 according to the first embodiment of the present disclosure. Figure 3 is a longitudinal cross-sectional view of the same blower 1. Figure 4 is an exploded perspective view illustrating the assembly of the fan case 2 of the same blower 1. The blower 1 is, for example, a blower for cooling a battery inside a vehicle. Specifically, the blower 1 is a centrifugal fan blower.

[0020] As shown in Figure 3, the blower 1 mainly consists of a fan case 2, a motor 10, and a centrifugal fan 3. The motor 10 and centrifugal fan 3 are housed inside the fan case 2. As shown in Figure 2, the fan case 2 has an intake port 15 for drawing in outside air, an exhaust port 16 for discharging air towards the outside space, and a circumferential passage 13 and an exhaust passage 14 that connect the intake port 15 and the exhaust port 16. The intake port 15 is circular. The exhaust port 16 is rectangular. Air is drawn into the fan case 2 from the intake port 15, flows through the circumferential passage 13 and the exhaust passage 14 in that order, and is discharged from the exhaust port 16.

[0021] Motor 10 is, for example, an inner rotor type brushless motor. Motor 10 is not limited to a brushless motor, but may be other types of DC motors or AC motors. In this embodiment, as shown in Figure 3, the direction in which the axis X1 of the rotation shaft 100 of motor 10 extends is defined as the axial direction A1. In a plane perpendicular to the axial direction A1, the direction perpendicular to the axis X1 is defined as the radial direction, and the direction that circles the axis X1 is defined as the circumferential direction.

[0022] As shown in Figures 2, 3, and 7, the centrifugal fan 3 has a bottom wall 31, a plurality of blades 32, a frame 33, and a balance adjustment section 36. The bottom wall 31 has a bottom surface 30 that intersects with the axis X1, which is the rotation center of the centrifugal fan 3. The plurality of blades 32 are arranged around the axis X1 and erected from the bottom surface 30 along the axial direction A1. The frame 33 is annular in shape, connecting the plurality of blades 32 at the ends of the plurality of blades 32 opposite the bottom wall 31 in the axial direction A1. The balance adjustment section 36 will be described later.

[0023] The centrifugal fan 3 is connected to the rotating shaft 100 of the motor 10 so as to rotate together with it. The blade members are made of metal or resin. The centrifugal fan 3 rotates at a predetermined speed in the circumferential direction in response to the rotation of the motor 10, thereby drawing in outside air from the intake port 15 and pumping it under pressure.

[0024] (1.1) Fan Case The fan case 2 is a hollow component made by molding resin. The fan case 2 has an air intake port 15 on its upper surface. The fan case 2 is substantially cylindrical in shape and houses the motor 10 and the centrifugal fan 3.

[0025] Specifically, as shown in Figure 2, the fan case 2 has an upper wall, side walls, and a lower wall that form a circumferential passage 13 and an exhaust passage 14. The fan case 2 is configured to cover the centrifugal fan 3. With this configuration, the circumferential passage 13 and the exhaust passage 14 are formed inside the fan case 2 along the outer circumference of the centrifugal fan 3. In plan view, the circumferential passage 13 extends in a circumferential shape so as to surround the outer circumference of the centrifugal fan 3. The exhaust passage 14 extends linearly in the exhaust direction B1 (one direction). The circumferential passage 13 is an internal space for guiding the air drawn in from the intake port 15 to the exhaust passage 14 when the centrifugal fan 3 rotates due to the rotational motion transmitted from the motor 10. The area of ​​the cross-section including the axis X1 in the circumferential passage 13 gradually increases as it approaches the exhaust passage 14.

[0026] The air intake port 15 is, for example, an intake for air from inside the vehicle. Of the substantially cylindrical fan case 2, the air intake port 15 is formed on the axial end face (upper end face in the figure) facing the vehicle interior. The air intake port 15 is an opening with an inner diameter that is approximately the same as or slightly smaller than that of the centrifugal fan 3. The air intake port 15 communicates with the vehicle interior via a duct (not shown).

[0027] The exhaust port 16 opens in a direction that is torsion relative to the axial direction. In other words, the air drawn in from the direction along the axis X1 of the centrifugal fan 3 toward the fan case 2 is exhausted in a direction that is torsion relative to the axis X1.

[0028] The fan case 2 is made of a resin such as polypropylene. As shown in Figures 3 and 4, the fan case 2 is divided into a lower first case 24 and an upper second case 25. As shown in Figure 4, the outer side surface of the first case 24 is provided with a plurality of protrusions 21 at predetermined intervals in the circumferential direction. The side surface of the second case 25 is provided with a plurality of hooks 22 at predetermined intervals in the circumferential direction. The first case 24 and the second case 25 are connected by the hooks 22 being engaged with the plurality of protrusions 21.

[0029] The intake port 15 is formed by the second case 25. The exhaust port 16 is formed by fitting the second case 25 and the first case 24 together.

[0030] As shown in Figure 3, the centrifugal fan 3 is fixed to the motor 10. The motor 10 is fixed to the first case 24.

[0031] As shown in Figures 2 and 4, the fan case 2 has a sealing sponge 19 for the exhaust port 16. More specifically, the first case 24 has the sealing sponge 19. The exhaust port 16 has an opening surface whose normal is a direction perpendicular to the axial direction A1. The fan case 2 has a flange 23 to which the sealing sponge 19 is attached. The flange 23 and the sealing sponge 19 are portions to which, for example, a duct (not shown) is fitted.

[0032] (1.1.1) First Case As shown in Figures 3 and 4, the first case 24 is a member that constitutes the lower part of the circumferential passage 13 and the exhaust passage 14. The first case 24 is cylindrical. The first case 24 has an annular planar portion 241 and a side portion 242. The side portion 242 is a portion that constitutes a generally cylindrical passage extending in the axial direction A1 from the outer peripheral edge of the annular planar portion 241.

[0033] As shown in Figure 2, a bracket 17 is formed near the inflection point Y1 (described later) of the side portion 242 of the first case 24 that corresponds to the exhaust passage 14.

[0034] (1.1.2) Second Case As shown in Figures 3 and 4, the second case 25 is a component that constitutes the upper part of the circumferential passage 13 and the exhaust passage 14. The second case 25 mainly has an annular planar portion 251 and a side portion 252. The annular planar portion 251 is a generally flat annular portion that constitutes the intake port 15. The side portion 252 is a portion that constitutes a generally cylindrical passage extending in the axial direction A1 from the outer peripheral edge of the annular planar portion 251. The side portion 252 is shorter than the side portion 242 of the first case 24 in the axial direction A1.

[0035] (1.2) Circular passage and exhaust passage In the circular passage 13, as shown in Figure 2, the side portion 242 of the first case 24 and the side portion 252 of the second case 25 constitute the circular passage side wall 11.

[0036] In the exhaust passage 14, the side portion 242 of the first case 24 and the side portion 252 of the second case 25 (see Figure 3) constitute the exhaust passage side wall 12, which is continuous with the circumferential passage side wall 11. Viewed from the axial direction A1, the circumferential passage side wall 11 is a combination of multiple curves with different curvatures. The exhaust passage side wall 12 is generally straight. The inflection point Y1 indicates the boundary between the circumferential passage side wall 11 and the exhaust passage side wall 12. The straight line Z1 extending from the inflection point Y1 and crossing the passage indicates the boundary between the circumferential passage 13 and the exhaust passage 14.

[0037] (1.3) Bracket blower 1 is fitted with brackets 17 and 18. Brackets 17 and 18 are components for fixing blower 1 to the vehicle frame. Brackets 17 and 18 are made of resin, for example, polypropylene. Brackets 17 and 18 are integrally formed with the first case 24.

[0038] (1.4) The mobile body 91 to which the mobile blower 1 is attached will be described with reference to Figure 5. Figure 5 is a schematic configuration diagram of a mobile body 91 to which the blower 1 is provided according to the first embodiment of the present disclosure. The mobile body 91 comprises the blower 1, a battery 92 (for the object to be cooled), a control device 93, a cable 94, a cable 96, and a vehicle body 95 (the main body of the mobile body).

[0039] The mobile vehicle 91 is a four-wheeled hybrid vehicle in which an engine (not shown) and a drive battery 92 are mounted on the vehicle body 95. The mobile vehicle 91 is not limited to a hybrid vehicle; it may also be an electric vehicle. The mobile vehicle 91 on which the blower 1 is mounted is not limited to a four-wheeled vehicle; it may also be a mobile vehicle (automobile) such as a two-wheeled vehicle or a three-wheeled vehicle. The object to be cooled may be a part other than the battery 92. The position on which the blower 1 is mounted on the mobile vehicle 91 may be any position.

[0040] The vehicle body 95 is equipped with a blower 1, a battery 92, a control device 93, a cable 94, and a cable 96.

[0041] The battery 92 is composed of, for example, a lithium-ion battery or a nickel-metal hydride battery. The battery 92 supplies power to the drive motor and other components used to propel the mobile unit 91.

[0042] The control device 93 is electrically connected to the blower 1 via cable 94. The control device 93 controls the blower 1. More specifically, the control device 93 is electrically connected to the motor drive circuit of the blower 1 via cable 94. The control device 93 controls the battery 92 via cable 96. More specifically, the control device 93 controls the power supply from other batteries to the blower 1 and the drive motor, etc.

[0043] The blower 1 used in the mobile unit 91 functions as a cooling fan system to suppress the temperature rise of the battery 92. When air is blown from the blower 1 towards the battery 92, the air is supplied to the battery 92. This cools the battery 92 by air, suppressing the temperature rise of the battery 92.

[0044] (2) Method for adjusting the rotational balance of the fan The method for adjusting the rotational balance of the fan according to this embodiment is a method for measuring the unbalance of the rotating body using an unbalance measuring device 4 and adjusting the rotational balance of the resin centrifugal fan 3 as the rotating body. As shown in Figure 1, the rotational balance adjustment method comprises a rotational reference position detection step (S10), an unbalance measurement step (S20), and an unbalance adjustment step (S30).

[0045] (2.1) Unbalance measuring device The unbalance measuring device 4 will be described. FIG. 6 is an explanatory view of the rotation detection device 40 in the unbalance measuring device 4. As shown in FIG. 6, the unbalance measuring device 4 is a device that measures the unbalance of a rotating body by detecting the rotation of the rotating body with a laser. The unbalance measuring device 4 can appropriately use various similar devices, including the device for measuring the mass unbalance of the rotating body described in Patent Document 3.

[0046] The unbalance measuring device 4 has a rotation detection device 40 that detects the rotation of the rotating body with a laser. The rotation detection device 40 has a light projecting unit 41 that projects a laser and a light receiving unit 42 that receives the laser. The rotation detection device 40 projects a laser from the light projecting unit 41 onto the bottom surface 30 of the bottom wall 31 of the centrifugal fan 3, which is a rotating body, and receives the laser reflected by the bottom surface 30 with the light receiving unit 42, and can detect the light amount and reflectivity of the received laser (the ratio of the light amount of the laser received by the light receiving unit 42 to the light amount of the laser projected from the light projecting unit 41).

[0047] When there are two regions with different surface roughness on the surface irradiated with the laser from the light projecting unit 41, that is, on the bottom surface 30 as the surface of the rotating body, the rotation detection device 40 can distinguish these two regions because the reflectivities of the laser in these two regions are different.

[0048] (2.2) Rotation reference position, reference display unit The rotation reference position is a position that serves as a reference for detecting the phase angle in the rotation about the axis X1 in the centrifugal fan 3. The phase angle of an arbitrary point in the centrifugal fan 3 is represented by an angle of 0 degrees or more and less than 360 degrees from the rotation reference position.

[0049] Figure 7 is a plan view of the centrifugal fan 3 included in the blower 1 according to the first embodiment of the present disclosure. As shown in Figure 7, the centrifugal fan 3 has a first region 34 on its surface that is different from the second region 35 other than the reference display section 5, as a reference display section 5 indicating the rotation reference position. The reflectivity of the laser in the first region 34 is configured to be different from the reflectivity of the laser in the second region 35. With this configuration, the rotation detection device 40 can distinguish the reference display section 5 (first region 34) on the bottom surface 30 of the rotating body (centrifugal fan 3) from other parts (second region 35). Details of the reference display section 5 will be described later.

[0050] The method for adjusting the rotational balance of a fan will be explained based on the flowchart shown in Figure 1. In step (S00), the execution of the fan rotational balance adjustment method is started.

[0051] (2.3) Rotation Reference Position Detection Step The rotation reference position detection step (S10) is a step in which the rotation reference position of the rotating centrifugal fan 3 is detected by transmitting and receiving light from the laser of the unbalance measuring device 4. The operator sets the centrifugal fan 3, which has a reference display unit 5 (first region 34), in the unbalance measuring device 4 as the rotating body to be measured for unbalance. The rotation detection device 40 of the unbalance measuring device 4 detects the reference display unit 5 on the rotating centrifugal fan 3 that has been set in the unbalance measuring device 4.

[0052] (2.4) Unbalance Measurement Step The unbalance measurement step (S20) is a step in which the phase angle of the eccentric position of the centrifugal fan 3 from the rotational reference position and the amount of unbalance are obtained as measurement results by the unbalance measuring device 4. The eccentric position (unbalance position) of the centrifugal fan 3 is the position of the center of gravity of the centrifugal fan 3 when viewed from the axial direction A1. The eccentric position (unbalance position) of the centrifugal fan 3 is expressed by the angle (phase angle) in the circumferential direction with the rotational reference position (reference display unit 5) as the starting point, with the axis X1 as the center. The amount of unbalance is expressed as the position of the center of gravity in the radial direction, that is, the distance of the center of gravity from the axis X1, or as a physical quantity such as gcm (gram-centimeter). The unbalance measuring device 4 has a minimum unit of measurable unbalance. For this reason, unbalance amounts less than the minimum unit cannot be effectively measured.

[0053] The unbalance measurement step (S20) is performed simultaneously with the rotation reference position detection step (S10). That is, while the centrifugal fan 3 set in the unbalance measuring device 4 is rotating, the rotation reference position detection and unbalance measurement are performed in parallel for each rotation. Naturally, the rotation reference position detected in the rotation reference position detection step (S10) is used to determine the eccentric position for each rotation.

[0054] (2.5) Unbalance adjustment step The rotation reference position detection step (S10) and the unbalance measurement step (S20) provide the phase angle of the eccentric position of the centrifugal fan 3 from the rotation reference position and the amount of unbalance as measurement results. After this, the unbalance adjustment step (S30) is performed.

[0055] The unbalance adjustment step (S30) is a step in which the amount of unbalance is reduced by adding mass to or removing a portion of the centrifugal fan 3 based on the measurement results. Details of the unbalance adjustment will be described later.

[0056] (3) Details of the Reference Display Unit The details of the reference display unit 5 will be explained. The first region 34, which will be the reference display unit 5, is provided on a part of the bottom surface 30. The bottom surface 30 is easy to form as the surface of the bottom wall 31, and is flat, with few irregularities or curves. The reference display unit 5 can easily maintain the direction that the bottom surface 30 faces (the normal vector of the bottom surface 30) even when the centrifugal fan 3 is rotating. For this reason, the bottom surface 30 of the bottom wall 31 is suitably selected as the part of the centrifugal fan 3 that can stably reflect the laser from the light-emitting unit 41 of the rotation detection device 40.

[0057] The reflectivity of the laser in the first region 34 is configured to be different from that of the laser in the second region 35. For example, by making the surface roughness of the first region 34 and the surface roughness of the second region 35 different from each other, the reflectivity of the laser in the first region 34 and the reflectivity of the laser in the second region 35 are made different from each other. With this configuration, the rotation detection device 40 can identify the reference display unit 5 (first region 34) on the bottom surface 30 of the rotating body (centrifugal fan 3) from other parts (second region 35). As a result, the unbalance measuring device 4 can recognize the reference display unit 5 without the operator performing the unbalance measurement having to attach the reference display unit 5 to the fan. This makes it easier to measure the unbalance of the fan.

[0058] The reflectance in the first region 34 is greater than the reflectance in the second region 35. If there is dirt or other debris on the reflective surface of the laser from the rotation detection device 40, the reflectance in this area will be detected as lower. Therefore, if the reflectance of the first region 34, which serves as the reference display unit 5, is set to be lower than the reflectance of the second region 35, the first region 34 will be falsely detected due to the detection of dirt or other debris. By setting the reflectance in the first region 34 to be greater than the reflectance in the second region 35, the false detection described above can be suppressed.

[0059] The first region 34 and the second region 35 are formed by resin molding of the main body 300 of the centrifugal fan 3. That is, when the centrifugal fan 3 (before unbalance adjustment) is molded using a mold by injection of molten resin and solidification by cooling, the first region 34 and the second region 35 are also molded with predetermined properties such as surface roughness. In this case, the surface roughness of the part of the mold cavity surface where the first region 34 is molded and the part where the second region 35 is molded are different.

[0060] When the first region 34 and the second region 35, which have predetermined properties, are formed simultaneously with the molding of the fan, there is absolutely no need for work to attach the reference display section 5.

[0061] (4) Details of unbalance adjustment Details of unbalance adjustment will be explained based on Figure 8. Figure 8 is a cross-sectional view of the main part of the centrifugal fan 3 according to the first embodiment of the present disclosure. The centrifugal fan 3 has a balance adjustment section 36. The balance adjustment section 36 is provided in the centrifugal fan 3 around the entire circumference of the axis X1. The balance adjustment section 36 is the part in which mass is added or removed in the unbalance adjustment step (S30).

[0062] The balance adjustment section 36 has an adjustment groove 36A that extends around the axis X1. The adjustment groove 36A is provided at the outermost diameter portion (frame portion 33) of the centrifugal fan 3, which is the furthest radially from the axis X1. The adjustment groove 36A is provided continuously around the entire circumference of the frame portion 33 of the centrifugal fan 3. The adjustment groove 36A is formed in an L-shape in cross-section, opening in a protruding direction (upward in Figure 8) and radially inward. The surface of the adjustment groove 36A that intersects the axial direction A1 faces the protruding direction. That is, the normal vector of the surface of the adjustment groove 36A that intersects the axial direction A1 is parallel to the axial direction A1.

[0063] The surface roughness of at least a portion of the inner surface of the adjustment groove 36A is greater than the surface roughness of the centrifugal fan 3 adjacent to the adjustment groove 36A. This makes it easier for mass, such as adhesive, to adhere to the adjustment groove 36A.

[0064] In the unbalance adjustment step (S30), the portion of the centrifugal fan 3 to which mass is added or removed is the portion of the centrifugal fan 3 other than the bottom wall 31. In other words, of the surface of the centrifugal fan 3, the surface on which rotation is detected by the rotation detection device 40 and the surface on which the balance adjustment unit 36 ​​is provided are different surfaces from each other.

[0065] In the unbalance adjustment step (S30), the operator adds mass such as adhesive to the adjustment groove 36A at a position in the adjustment groove 36A that is at a phase angle opposite to the eccentric position with respect to the axis X1, based on the measurement results obtained in the unbalance measurement step (S20). At this time, the adjustment groove 36A is formed continuously over the entire circumference in the circumferential direction. This allows mass to be added at any phase angle position, enabling high-precision unbalance adjustment. The adjustment groove 36A is formed in an L-shape in cross-section that opens in a protruding direction and inward in diameter. This makes it easy to insert mass into the adjustment groove 36A, and the adjustment groove 36A does not open outward in diameter. Therefore, the mass added by centrifugal force due to the rotation of the centrifugal fan 3 is less likely to detach from the centrifugal fan 3.

[0066] The balance adjustment section 36 is provided on the frame portion 33 at the tip of the multiple blades 32 that protrude cantilevered from the bottom wall 31. Therefore, a greater balance adjustment effect can be obtained compared to the case where the balance adjustment section 36 is provided on the bottom wall 31. The reason for this is that as the centrifugal fan 3 rotates, the added mass moves slightly outward due to centrifugal force, increasing the radius of rotation of the added mass from the axis X1, resulting in a larger moment and a greater balance adjustment effect.

[0067] (Second Embodiment) The second embodiment will be described using Figure 9. Figure 9 is a cross-sectional view of the main part of the centrifugal fan 3 of the second embodiment. The basic configuration of the second embodiment is the same as that of the first embodiment, so the differences will be explained in detail.

[0068] The adjustment groove 36B is formed in an L-shape in cross-section, opening in a protruding direction (upward in Figure 9) and radially inward. The surface of the adjustment groove 36B that intersects the axial direction A1 is oriented in a direction that is inclined radially outward from the protruding direction. That is, the normal vector of the surface of the adjustment groove 36B that intersects the axial direction A1 is not parallel to the axial direction A1. In the second embodiment, the mass added to the adjustment groove 36B is less likely to fall out of the adjustment groove 36B.

[0069] (Third Embodiment) The third embodiment will be described using Figure 10. Figure 10 is a cross-sectional view of the main part of the centrifugal fan 3 of the third embodiment. The basic configuration of the third embodiment is the same as that of the first embodiment, so the differences will be explained in detail.

[0070] The adjustment groove 36C is formed in a U-shape with a cross-section that opens in a protruding direction (upward in Figure 10). In the third embodiment, the mass added to the adjustment groove 36C is less likely to fall out of the adjustment groove 36C.

[0071] (Fourth Embodiment) The fourth embodiment will be described using Figure 11. Figure 11 is a cross-sectional view of the main part of the centrifugal fan 3 of the fourth embodiment. The basic configuration of the fourth embodiment is the same as that of the first embodiment, so the differences will be explained in detail.

[0072] The adjustment groove 36D is formed in a rectangular cross-section with a roughly U-shaped cross-section that opens in a protruding direction (upward in Figure 11). In the fourth embodiment, the mass attached to the adjustment groove 36D is less likely to fall out of the adjustment groove 36D.

[0073] (Fifth Embodiment) The fifth embodiment will be described using Figure 12. Figure 12 is a cross-sectional view of the main part of the centrifugal fan 3 of the fifth embodiment. The basic configuration of the fifth embodiment is the same as that of the first embodiment, so the differences will be explained in detail.

[0074] The balance adjustment unit 36 ​​has a removal unit 37 that protrudes radially outward from the main body 300 of the centrifugal fan 3. The removal unit 37 is provided at the outermost diameter portion (frame portion 33) of the centrifugal fan 3, which is furthest radially from the axis X1. Furthermore, the removal unit 37 is provided continuously around the entire circumference of the frame portion 33 of the centrifugal fan 3.

[0075] In the unbalance adjustment step (S30), the operator removes a portion of the removal section 37 using a cutting means such as a cutter, at a point in the removal section 37 that has the same phase angle as the eccentric position with respect to the axis X1, based on the measurement results obtained in the unbalance measurement step (S20). At this time, the removal section 37 is formed continuously over the entire circumference in the circumferential direction. This makes it possible to remove mass at any phase angle position, enabling high-precision unbalance adjustment.

[0076] (Sixth Embodiment) The sixth embodiment will be described using Figures 13 to 15. Figure 13 is a cross-sectional view of the main part of the centrifugal fan 3 of the sixth embodiment. Figure 14 is a plan view of the same centrifugal fan 3. Figure 15 is a perspective view of the main part of the same centrifugal fan 3. The basic configuration of the sixth embodiment is the same as that of the first embodiment, so the differences will be explained in detail.

[0077] The removal section 37 is provided with a plurality of removal blocks 37A arranged at intervals around the axis X1. The removal blocks 37A are configured such that when one block is removed, the smallest unit of unbalance (gcm) that can be measured by the unbalance measuring device 4 decreases. This enables high-precision unbalance adjustment.

[0078] The centrifugal fan 3 further includes a connecting portion 38 that connects a plurality of removal blocks 37A to the main body portion 300 of the centrifugal fan 3. The connecting portion 38 is annular in shape around the axis X1. That is, while the removal blocks 37A are provided discretely in the circumferential direction, the connecting portion 38 is provided continuously in the circumferential direction. This makes it easier to manufacture the centrifugal fan 3 compared to the case where the connecting portion 38 is provided discretely, and also makes it easier for the centrifugal fan 3 to rotate stably.

[0079] The length of the connecting portion 38 in the axial direction A1 is smaller than the length of the multiple removal blocks 37A in the axial direction A1. When removing the removal blocks 37A, the connecting portion 38 can be cut to remove the removal portion 37, making it easier to remove the removal portion 37.

[0080] The length of the multiple removal blocks 37A in the axial direction A1 is smaller than the length of the multiple removal blocks 37A around the axis X1. In other words, the shape of the removal blocks 37A in a side view is formed to be elongated in the direction along the rotation direction. As a result, vibration caused by the removal blocks 37A is less likely to occur when the centrifugal fan 3 rotates.

[0081] Each of the multiple removal blocks 37A has a fillet 391 at at least one end in the axial direction A1. The fillet 391 is formed at the end of the removal block 37A facing forward in the direction of travel due to the rotation of the centrifugal fan 3. As a result, even if air collides with the end of the removal block 37A facing forward in the direction of travel due to the rotation of the centrifugal fan 3, the fillet 391 suppresses turbulence in the airflow.

[0082] Multiple removal blocks 37A may have fillets at both ends in the axial direction A1. This suppresses turbulence as the air flowing along the removal blocks 37A moves away from the removal blocks 37A. Thus, turbulence in the airflow is further suppressed.

[0083] Each of the multiple removal blocks 37A has a fillet 392 at its radially outward-facing end and protruding end. A portion of the air that flows radially outward through the blades 32 returns to the inside of the centrifugal fan 3 through the upper side (protruding side) of the frame 33. At this time, the turbulent airflow caused by the removal blocks 37A is mitigated by the fillet 392, thereby suppressing turbulence in the airflow.

[0084] (Seventh Embodiment) The seventh embodiment will be described using Figure 16. Figure 16 is a cross-sectional view of the main part of the centrifugal fan 3 of the seventh embodiment. The basic configuration of the seventh embodiment is the same as that of the first embodiment, so the differences will be explained in detail.

[0085] In the first embodiment, the surface roughness of the first region 34 and the surface roughness of the second region 35 are made different from each other, thereby making the laser reflectance in the first region 34 and the laser reflectance in the second region 35 different from each other.

[0086] In contrast, in the seventh embodiment, the first region 34 is made to protrude from the second region 35, thereby making the reflectivity of the laser in the first region 34 and the reflectivity of the laser in the second region 35 different from each other.

[0087] (Modification) In the above embodiment, the rotating body is a centrifugal fan 3. The centrifugal fan 3 as the rotating body is, for example, a turbo fan or a sirocco fan. The rotating body may be an axial fan instead of a centrifugal fan 3.

[0088] The first region 34 and the second region 35 may be formed by surface treatment of the fan body after resin molding of the fan body. In this case, it is not necessary to create the first region 34 and the second region 35 with predetermined properties at the same time as molding the fan. Therefore, the degree of design freedom, including the design of the mold, is improved.

[0089] The reflectance in the first region 34 may be less than the reflectance in the second region 35.

[0090] The first region 34 may be provided in a portion of the bottom wall 31 of the centrifugal fan 3 other than the bottom surface 30.

[0091] The rotation reference position detection step (S10) and the unbalance measurement step (S20) do not necessarily have to be performed at the same time.

[0092] The surface roughness in the first region 34 may be the same as the surface roughness in the second region 35. That is, instead of making the surface shapes of the first region 34 and the second region 35 different, the laser reflectance in the first region 34 and the laser reflectance in the second region 35 may be made different, for example, by making the colors of the first region 34 and the second region 35 different.

[0093] (Aspects) The following aspects are disclosed in this specification.

[0094] The first embodiment of the fan rotation balance adjustment method is a method for adjusting the rotation balance of a resin fan as a rotating body using an unbalance measuring device (4) that detects the rotation of a rotating body with a laser and measures the unbalance of the rotating body. The rotation balance adjustment method comprises a rotation reference position detection step (S10), an unbalance measurement step (S20), and an unbalance adjustment step (S30). The rotation reference position detection step (S10) is a step of detecting the rotation reference position of the rotating fan by transmitting and receiving light from the laser of the unbalance measuring device (4). The unbalance measurement step (S20) is a step of obtaining the phase angle of the eccentric position of the fan from the rotation reference position and the amount of unbalance as measurement results from the unbalance measuring device (4). The unbalance adjustment step (S30) is a step of adjusting the amount of unbalance by adding mass to a part of the fan or removing a part of the fan based on the measurement results. The fan has a first region (34) on its surface that is different from the second region (35) other than the reference region (5), which serves as a reference indicator (5) for indicating the rotational reference position. The reflectivity of the laser in the first region (34) is different from the reflectivity of the laser in the second region (35).

[0095] In this embodiment, the unbalance measuring device (4) can recognize the reference display unit (5) without the operator performing the unbalance measurement having to attach the reference display unit (5) to the fan. This makes it easier to measure the unbalance of the fan.

[0096] The second embodiment of the fan rotation balance adjustment method is a method for adjusting the rotation balance of a resin fan as a rotating body using an unbalance measuring device (4) that detects the rotation of a rotating body with a laser and measures the unbalance of the rotating body. The rotation balance adjustment method comprises a rotation reference position detection step (S10), an unbalance measurement step (S20), and an unbalance adjustment step (S30). The rotation reference position detection step (S10) is a step of detecting the rotation reference position of the rotating fan by transmitting and receiving light from the laser of the unbalance measuring device (4). The unbalance measurement step (S20) is a step of obtaining the phase angle of the eccentric position of the fan from the rotation reference position and the amount of unbalance as measurement results from the unbalance measuring device (4). The unbalance adjustment step (S30) is a step of adjusting the amount of unbalance by adding mass to a part of the fan or removing a part of the fan based on the measurement results. The fan has a first region (34) on its surface that is different from the second region (35) other than the reference region (5), which serves as a reference indicator (5) for indicating the rotation reference position. The first region (34) protrudes from the second region (35).

[0097] In this embodiment, the unbalance measuring device (4) can recognize the reference display unit (5) without the operator performing the unbalance measurement having to attach the reference display unit (5) to the fan. This makes it easier to measure the unbalance of the fan.

[0098] A fan rotation balance adjustment method according to the third embodiment can be realized by combining it with the first embodiment. In the third embodiment, the surface roughness in the first region (34) is different from the surface roughness in the second region (35).

[0099] According to this embodiment, the unbalance measuring device (4) can recognize the reference display unit (5) without the operator performing the unbalance measurement having to attach the reference display unit (5) to the fan.

[0100] A fan rotation balance adjustment method according to the fourth embodiment can be realized by combining it with the first or third embodiment. In the fourth embodiment, the reflectance in the first region (34) is greater than the reflectance in the second region (35).

[0101] According to this embodiment, it is possible to suppress false detections by the unbalance measuring device (4) in the reference display unit (5).

[0102] The fifth embodiment of the fan rotation balance adjustment method can be realized by combining it with any of the first, third, or fourth embodiments. In the fifth embodiment, the first region (34) and the second region (35) are formed by resin molding of the fan body.

[0103] According to this embodiment, a first region (34) and a second region (35) having predetermined properties are formed simultaneously with the molding of the fan. Therefore, there is no need to perform any work to attach the reference indicator section (5).

[0104] The fan rotation balance adjustment method according to the sixth embodiment can be realized by combining it with any of the first, third, or fourth embodiments. In the sixth embodiment, the first region (34) and the second region (35) are formed by surface processing of the fan body after resin molding of the fan body.

[0105] According to this embodiment, it is not necessary to create the first region (34) and the second region (35) having predetermined properties at the same time as molding the fan. Therefore, the degree of design freedom, including the design of the mold, is improved.

[0106] A method for adjusting the rotational balance of a fan according to the seventh embodiment can be realized by combining it with any of the first to sixth embodiments. In the seventh embodiment, the fan has a bottom wall (31), a plurality of blades (32), and a frame (33). The bottom wall (31) has a bottom surface (30) that intersects with the axis (X1) which is the rotation center of the fan. The plurality of blades (32) are arranged around the axis (X1) and erected from the bottom surface (30) along the axial direction (A1). The frame (33) is annular in shape, connecting the plurality of blades (32) at the ends of the plurality of blades (32) opposite the bottom wall (31) in the axial direction (A1). A first region (34) is provided on a part of the bottom surface (30).

[0107] According to this embodiment, the reflection of the laser by the unbalance measuring device (4) can be performed stably.

[0108] The fan rotation balance adjustment method according to the eighth embodiment can be realized by combining it with the seventh embodiment. In the eighth embodiment, the part of the fan to which mass is added or removed in the unbalance adjustment step (S30) is a part other than the bottom wall (31) of the fan.

[0109] A fan according to the ninth embodiment can be realized by combining it with any of the first to eighth embodiments. The fan according to the ninth embodiment is a resin fan whose rotational balance is adjusted by the fan rotational balance adjustment method described in any of the first to eighth embodiments. The fan has a bottom wall (31), a plurality of blades (32), a frame (33), and a balance adjustment part (36). The bottom wall (31) has a bottom surface (30) that intersects with the axis (X1) which is the rotation center of the fan. The plurality of blades (32) are arranged around the axis (X1) and protrude from the bottom surface (30) in a direction along the axial direction (A1). The frame (33) is annular in shape, connecting the plurality of blades (32) at the ends of the plurality of blades (32) opposite the bottom wall (31) in the axial direction (A1). The balance adjustment section (36) is provided around the entire circumference of the axis (X1), and mass is added or removed in the unbalance adjustment step (S30).

[0110] In this embodiment, the unbalance measuring device (4) can recognize the reference display unit (5) without the operator performing the unbalance measurement having to attach the reference display unit (5) to the fan. This makes it easier to measure the unbalance of the fan.

[0111] A fan according to the tenth embodiment can be realized by combining it with the ninth embodiment. In the tenth embodiment, the balance adjustment unit (36) is provided on the outermost diameter portion of the fan that is radially furthest from the axis (X1).

[0112] In this embodiment, the added mass moves slightly outward due to centrifugal force, increasing the radius of rotation of the added mass from its axis (X1). This results in a larger moment and a greater effect on balancing.

[0113] The fan according to the eleventh embodiment can be realized by combining it with the ninth embodiment. In the eleventh embodiment, the balance adjustment unit (36) is provided on the frame (33).

[0114] According to this embodiment, the effect of balance adjustment can be greatly enhanced compared to the case where the balance adjustment unit (36) is provided on the bottom wall (31).

[0115] A fan according to the twelfth embodiment can be realized by combining it with any of the ninth to eleventh embodiments. In the twelfth embodiment, the balance adjustment section (36) has adjustment grooves (36A, 36B, 36C, 36D) that extend around the axis (X1).

[0116] According to this embodiment, mass can be added at any phase angle position. This enables high-precision unbalance adjustment.

[0117] A fan according to the 13th embodiment can be realized by combining it with the 12th embodiment. In the 13th embodiment, the surface roughness of at least a portion of the inner surface of the adjustment grooves (36A, 36B, 36C, 36D) is greater than the surface roughness of the fan surface adjacent to the adjustment grooves (36A, 36B, 36C, 36D).

[0118] According to this embodiment, the mass consisting of adhesive or the like is more likely to adhere to the adjustment groove (36A).

[0119] A fan according to the 14th embodiment can be realized by combining it with the 12th or 13th embodiment. In the 14th embodiment, the adjustment grooves (36C, 36D) are formed in a U-shape in cross-section that opens in a protruding direction.

[0120] In this embodiment, the adjustment grooves (36C, 36D) do not open radially outward. Therefore, the mass added by centrifugal force due to the rotation of the centrifugal fan (3) is less likely to detach from the centrifugal fan (3).

[0121] A fan according to the 15th embodiment can be realized by combining it with the 12th or 13th embodiment. In the 15th embodiment, the adjustment grooves (36A, 36B) are formed in an L-shape in cross-section, opening in a protruding direction and in a radially inward direction.

[0122] In this embodiment, the mass is easily inserted into the adjustment grooves (36A, 36B), and the adjustment grooves (36A, 36B) do not open radially outward. Therefore, the mass added by centrifugal force due to the rotation of the centrifugal fan (3) is less likely to detach from the centrifugal fan (3).

[0123] The fan according to the 16th embodiment can be realized by combining it with any of the 9th to 11th embodiments. In the 16th embodiment, the balance adjustment unit (36) has a removal unit (37) that protrudes radially outward from the main body of the fan.

[0124] According to this embodiment, the imbalance can be adjusted simply by cutting off a portion of the centrifugal fan (3).

[0125] A fan according to the 17th embodiment can be realized by combining it with the 16th embodiment. In the 17th embodiment, a plurality of removal blocks (37A) are provided as the removal section (37), which are arranged at intervals around the axis (X1).

[0126] According to this embodiment, high-precision unbalance adjustment becomes possible.

[0127] A fan according to the 18th embodiment can be realized by combining it with the 17th embodiment. In the 18th embodiment, the fan further has a connecting portion (38) that connects a plurality of removal blocks (37A) to the main body. The length of the connecting portion (38) in the axial direction (A1) is smaller than the length of the plurality of removal blocks (37A) in the axial direction (A1).

[0128] According to this embodiment, when removing the removal block (37A), the connecting portion (38) can be cut and the removal portion (37) can be removed. Therefore, the removal portion (37) is easier to remove.

[0129] A fan according to the 19th embodiment can be realized by combining it with the 18th embodiment. In the 19th embodiment, the connecting portion (38) is annular around the axis (X1).

[0130] According to this embodiment, the manufacturing of the centrifugal fan (3) becomes easier, and when the centrifugal fan (3) rotates, the rotation becomes more stable.

[0131] The fan according to the 20th embodiment can be realized in combination with any of the 17th to 19th embodiments. In the 20th embodiment, the length of the plurality of removal blocks (37A) in the axial direction (A1) is smaller than the length of the plurality of removal blocks (37A) around the axis (X1).

[0132] According to this embodiment, vibrations caused by the removal block (37A) are less likely to occur when the centrifugal fan (3) rotates.

[0133] A fan according to the 21st embodiment can be realized in combination with any of the 17th to 20th embodiments. In the 21st embodiment, a plurality of removal blocks (37A) have a fillet (391) at at least one end in the axial direction (A1).

[0134] According to this embodiment, turbulence in the airflow is suppressed.

[0135] A fan according to the 22nd embodiment can be realized by combining it with the 21st embodiment. In the 22nd embodiment, the plurality of removal blocks (37A) have fillets at both ends in the axial direction (A1).

[0136] According to this embodiment, turbulence is suppressed when the air flowing along the removal block (37A) moves away from the removal block (37A). This further suppresses turbulence in the airflow.

[0137] A fan according to the 23rd embodiment can be realized in combination with any of the 17th to 22nd embodiments. In the 23rd embodiment, the plurality of removal blocks (37A) have fillets (392) at their radially outward-facing ends and protruding ends.

[0138] In this embodiment, a portion of the air that flows radially outward through the blades (32) returns to the inside of the centrifugal fan (3) through the protruding side of the frame (33). At this time, the turbulent airflow caused by the removal block (37A) is mitigated by the fillet (392). This suppresses turbulence in the airflow.

[0139] 3 Centrifugal fan (fan) 30 Bottom surface 31 Bottom wall 32 Blades 33 Frame 34 First area 35 Second area 36 Balance adjustment section 36A Adjustment groove 36B Adjustment groove 36C Adjustment groove 36D Adjustment groove 37 Removal section 37A Removal block 38 Connecting section 300 Main body 391 Fillet 392 Fillet 4 Unbalance measuring device 5 Reference display section A1 Axial direction X1 Axial

Claims

1. A method for adjusting the rotational balance of a fan, which is a resin fan, by using an unbalance measuring device that detects the rotation of a rotating body using a laser and measures the unbalance of the rotating body, comprising: a rotation reference position detection step of detecting the rotation reference position of the rotating fan by transmitting and receiving light from the laser of the unbalance measuring device; an unbalance measurement step of obtaining the phase angle of the eccentric position of the fan from the rotation reference position and the amount of unbalance as measurement results from the unbalance measuring device; and an unbalance adjustment step of adjusting the amount of unbalance by adding mass to a part of the fan or removing a part of the fan based on the measurement results, wherein the fan has a first region on the surface of the fan that is different from a second region other than the reference display portion, as a reference display portion indicating the rotation reference position, and the reflectivity of the laser in the first region is different from the reflectivity of the laser in the second region.

2. A method for adjusting the rotational balance of a fan, which is a resin fan, by using an unbalance measuring device that detects the rotation of a rotating body using a laser and measures the unbalance of the rotating body, comprising: a rotation reference position detection step of detecting the rotation reference position of the rotating fan by transmitting and receiving light from the laser of the unbalance measuring device; an unbalance measurement step of obtaining the phase angle of the eccentric position of the fan from the rotation reference position and the amount of unbalance as measurement results from the unbalance measuring device; and an unbalance adjustment step of adjusting the amount of unbalance by adding mass to a part of the fan or removing a part of the fan based on the measurement results, wherein the fan has a first region on the surface of the fan that is different from a second region other than the reference display portion, as a reference display portion indicating the rotation reference position, and the first region protrudes from the second region.

3. The method for adjusting the rotational balance of a fan according to claim 1, wherein the surface roughness in the first region is different from the surface roughness in the second region.

4. The method for adjusting the rotational balance of a fan according to claim 1 or 3, wherein the reflectance in the first region is greater than the reflectance in the second region.

5. The method for adjusting the rotational balance of a fan according to claim 1, 3, or 4, wherein the first region and the second region are formed by resin molding of the main body of the fan.

6. The method for adjusting the rotational balance of a fan according to claim 1, 3, or 4, wherein the first region and the second region are formed by surface processing of the main body after resin molding of the main body of the fan.

7. The fan comprises a bottom wall having a bottom surface intersecting the axis which is the rotation center of the fan, a plurality of blades arranged around the axis and erected from the bottom surface along the axial direction, and an annular frame portion connecting the plurality of blades at the ends of the plurality of blades opposite the bottom wall in the axial direction, wherein the first region is provided on a part of the bottom surface, the method for adjusting the rotational balance of a fan according to any one of claims 1 to 6.

8. The method for adjusting the rotational balance of a fan according to claim 7, wherein the part of the fan to which mass is added or removed in the unbalance adjustment step is a part of the fan other than the bottom wall.

9. A resin fan whose rotational balance is adjusted by the fan rotational balance adjustment method described in claim 1 or 2, comprising: a bottom wall having a bottom surface intersecting the axis which is the rotation center of the fan; a plurality of blades arranged around the axis and protruding from the bottom surface in a direction along the axis; an annular frame portion connecting the plurality of blades at the ends of the plurality of blades opposite the bottom wall in the axial direction; and a balance adjustment portion provided around the entire circumference of the axis, in which mass is added or removed in the unbalance adjustment step.

10. The fan according to claim 9, wherein the balance adjustment section is provided at the outermost diameter portion of the fan, which is radially furthest from the axis.

11. The fan according to claim 9, wherein the balance adjustment unit is provided on the frame.

12. The fan according to claim 9, wherein the balance adjustment section has an adjustment groove extending around the axis.

13. The fan according to claim 12, wherein the surface roughness of at least a portion of the inner surface of the adjustment groove is greater than the surface roughness of the fan surface adjacent to the adjustment groove.

14. The fan according to claim 12 or 13, wherein the adjustment groove is formed in a U-shaped cross-section that opens in the direction of the protrusion.

15. The fan according to claim 12 or 13, wherein the adjustment groove is formed in an L-shape in cross-section that opens in the direction of protrusion and inward in diameter.

16. The fan according to any one of claims 9 to 11, wherein the balance adjustment section has a removal section that protrudes radially outward from the main body of the fan.

17. The fan according to claim 16, wherein the removal section is provided with a plurality of removal blocks arranged at intervals around the axis.

18. The fan according to claim 17, further comprising a connecting portion that connects the plurality of removal blocks and the main body, wherein the length of the connecting portion in the axial direction is smaller than the length of the plurality of removal blocks in the axial direction.

19. The fan according to claim 18, wherein the connecting portion is annular around the axis.

20. The fan according to any one of claims 17 to 19, wherein the length of the plurality of removal blocks in the axial direction is smaller than the length of the plurality of removal blocks around the axis.

21. The fan according to any one of claims 17 to 20, wherein the plurality of removal blocks each have a fillet at at least one end in the axial direction.

22. The fan according to claim 21, wherein the plurality of removal blocks have the fillets at both ends in the axial direction.

23. The fan according to any one of claims 17 to 22, wherein the plurality of removal blocks have fillets at the radially outward end and the protruding end.

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