Cooling fans and electronic devices

Abstract

According to the present invention, the amount of ingredients and dust in the air that adhere to components on a circuit board provided to a cooling fan is reduced. A cooling fan (10) comprises a base plate (40), which comprises an annular outer circumferential base portion (41) and a central base portion (42) positioned inside of the outer circumferential base portion (41). The cooling fan (10) has an electric motor (60) that is positioned below the central base portion (42), a circuit board (70) that is positioned between the electric motor (60) and the central base portion (42) and that is for driving the electric motor (60), and a peripheral wall portion (55) that encloses the outer peripheral edge of the circuit board (70).

Description

[Technical Field]

[0001] The present disclosure relates to a cooling fan and an electronic device. [Background technology]

[0002] Cooling fans are installed inside electronic devices such as game consoles, personal computers, and server computers to cool heat-generating components such as CPUs (Central Processing Units) and GPUs (Graphics Processing Units) mounted on circuit boards. An air intake port is formed in the exterior member of the electronic device to introduce outside air. Patent Document 1 listed below discloses an example of such an electronic device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 193879 Summary of the Invention [Problem to be solved by the invention]

[0004] A cooling fan has a circuit board on which various electronic components are mounted, such as a switching element (FET) that controls the current supplied to the motor and a control IC that controls the switching element in response to an externally input signal. Depending on the relative position of the cooling fan and the air intake port formed in the exterior material of the electronic device, and the environment in which the electronic device is used, components and dust contained in the air drawn in through the air intake port may adhere to the electronic components on the circuit board. [Means for solving the problem]

[0005] The cooling fan proposed in this disclosure includes a base plate having an annular outer base portion and a central base portion located inside the outer base portion, an electric motor having a rotating shaft and located on a first axial side of the central base portion, an impeller located radially outward of the electric motor and rotated by driving the electric motor, a circuit board for driving the electric motor located between the electric motor and the central base portion, and a peripheral wall portion surrounding the outer peripheral edge of the circuit board.

[0006] The electronic device proposed in the present disclosure includes the cooling fan and a housing that houses the cooling fan.

[0007] In this cooling fan and electronic device, the amount of airborne components and dust that adheres to components on the circuit board can be reduced by the peripheral wall portion. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a perspective view showing an example of a cooling fan proposed in the present disclosure. [Figure 2A] This is a cross-sectional view of the cooling fan taken along the axial direction, showing the cooling fan mounted in an electronic device, with the upper and lower sides of the cooling fan covered by exterior panels of the electronic device. [Figure 2B] FIG. 2B is an enlarged view of FIG. 2A. [Figure 3A] 10A and 10B are diagrams illustrating an example of the positional relationship between a circuit board, components arranged on the circuit board, and a peripheral wall portion, and show the circuit board and the like as viewed in the axial direction. [Figure 3B] 10 is a diagram showing another example of the positional relationship between the circuit board, components arranged on the circuit board, and the peripheral wall portion, and the circuit board etc. is shown as viewed in the axial direction. [Figure 3C] 10 is a diagram showing yet another example of the positional relationship between the circuit board, components arranged on the circuit board, and the peripheral wall portion, and shows the circuit board and the like as viewed in the axial direction. [Figure 4A]1 is a perspective view showing an example of an electronic device equipped with the cooling fan shown in FIG. 1 etc.; [Figure 4B] FIG. 4B is an exploded perspective view of the electronic device shown in FIG. 4A. DETAILED DESCRIPTION OF THE INVENTION

[0009] The cooling fan and electronic device proposed in this disclosure will be described below with reference to the drawings. In this disclosure, as an example, a cooling fan 10 (see FIG. 1) and an electronic device 90 (see FIG. 4A) will be described.

[0010] Hereinafter, the Z1 and Z2 directions shown in Figure 1 and other figures will be referred to as the upward and downward directions, respectively. Furthermore, in Figure 4A showing the electronic device 90, the X1 and X2 directions will be referred to as the right and left directions, respectively, and the Y1 and Y2 directions will be referred to as the forward and backward directions, respectively. These directions are defined to explain the shapes of the elements (components, members, and parts) of the cooling fan 10 and the electronic device 90 and their relative positional relationships. Therefore, the directions shown in the figures do not limit the orientation of the cooling fan 10 and the electronic device 90 during use.

[0011] [Impeller and motor housing] 1, cooling fan 10 has an impeller 20. Impeller 20 is rotatable about an axis C1 that runs along the vertical direction. Impeller 20 has a plurality of fins 21 that are aligned in the rotational direction.

[0012] As shown in FIG. 2A, the cooling fan 10 has an electric motor 60. The electric motor 60 has a rotating shaft 63, a stator 62, and a rotor 61 arranged on the outer periphery of the stator 62. The cooling fan 10 also has a motor housing 30 at its center that houses the electric motor 60. The motor housing 30 has a cylindrical portion 30a and a bottom portion 30b located at the lower end of the cylindrical portion 30a. The rotor 61 is fixed to the inner circumferential surface of the cylindrical portion 30a. The impeller 20 is fixed to the motor housing 30 and rotates together with the motor housing 30 when driven by the electric motor 60. The impeller 20 and the motor housing 30 may be integrally molded from resin.

[0013] The electric motor 60 and the impeller 20 may be circular in plan view. As shown in FIG. 2A , the impeller 20 may be located radially outward of the electric motor 60 and / or the rotary shaft 63 relative to the electric motor 60. The fins 21 of the impeller 20 extend from the outer circumferential surface of the motor housing 30 toward the radially outward side of the impeller 20. As shown in FIG. 2A , when the impeller 20 rotates, air F1, F2, F3, and F4 are introduced into the impeller 20 from the upper and lower sides of the impeller 20 and are discharged radially outward of the impeller 20.

[0014] [Base plate] As shown in FIG. 1 , the cooling fan 10 has a base plate 40. The base plate 40 may be formed of, for example, a metal plate. The base plate 40 is disposed on one side of the impeller 20 in the direction in which the rotation shaft 63 of the electric motor 60 extends (for example, the vertical direction; hereinafter, referred to as the axial direction). When the cooling fan 10 is mounted in the electronic device 90, the base plate 40 may be disposed in a position where it is located above the impeller 20, or conversely, the base plate 40 may be disposed in a position where it is located below the impeller 20.

[0015] 1, the base plate 40 has an annular outer peripheral base portion 41. A plurality of mounting portions 41a are formed on the outer peripheral base portion 41. The mounting portions 41a protrude from the outer peripheral edge of the outer peripheral base portion 41 in the radial direction of the outer peripheral base portion 41. The mounting portions 41a are fixed to the electronic device 90 by fasteners such as screws or bolts. The mounting portions 41a are fixed to the housing or frame of the electronic device 90, for example.

[0016] As shown in FIG. 1 , the base plate 40 has a central base portion 42 located inside the outer periphery base portion 41. A gap is formed between the inner peripheral edge of the outer periphery base portion 41 and the outer peripheral edge of the central base portion 42. The base plate 40 also has multiple connecting portions 43 connecting the outer periphery base portion 41 and the central base portion 42. The multiple connecting portions 43 are aligned in the rotational direction of the impeller 20. Each connecting portion 43 may extend in a direction oblique to both the radial direction and the rotational direction of the impeller 20. The base plate 40 may also have an annular guard portion 44 located between the outer periphery base portion 41 and the central base portion 42. The connecting portions 43 and the guard portion 44 allow the gap (intake port) formed between the outer periphery base portion 41 and the central base portion 42 to be divided into multiple regions. Unlike the example shown in FIG. 1 , the base plate 40 does not necessarily have to have the guard portion 44.

[0017] [Electric motor support structure] As shown in FIG. 2A, the electric motor 60 is located on one axial side (first side, the lower side in FIG. 2A) of the central base portion 42 of the base plate 40. A support portion 50 is also formed on the base plate 40. The support portion 50 has a fixed portion 51 and a motor support portion 52. The fixed portion 51 is formed on, for example, the upper surface of the central base portion 42. The motor support portion 52 extends from the central base portion 42 toward one axial side (the lower side in the example shown in the figure) and is located inside the motor housing 30. The stator 62 is supported by the motor support portion 52. For example, the stator 62 is attached to the outer peripheral surface of the motor support portion 52. The rotor 61 is attached to the inner peripheral surface of the cylindrical portion 30a of the motor housing 30 and surrounds the outer peripheral surface of the stator 62.

[0018] The support portion 50 may be made of, for example, resin. The fixed portion 51 and the motor support portion 52 may be connected to each other, for example, via one or more holes that penetrate the central base portion 42 of the base plate 40. The support portion 50 may be formed by insert molding with the base plate 40. That is, the base plate 40 may be placed inside a mold for forming the support portion 50, and resin may be supplied into the mold to form the support portion 50 using the resin.

[0019] The motor support portion 52 may be formed in a cylindrical shape. As shown in Fig. 2A, a rotating shaft 63 of the electric motor 60 may be disposed inside the motor support portion 52. The rotating shaft 63 may be supported inside the motor support portion 52 via a bearing. The rotating shaft 63 is coupled to the motor housing 30 and is rotatable integrally with the motor housing 30.

[0020] [Circuit board] 2A, the cooling fan 10 has a circuit board 70. A plurality of components 71 for driving the electric motor 60 are mounted on the circuit board 70. The components 71 include, for example, a switching element that controls the current supplied to the electric motor 60 and a control IC (Integrated Circuit) that controls the switching element. For example, a MOSFET (metal-oxide-semiconductor field-effect transistor) can be used as the switching element.

[0021] The control IC outputs an on / off signal for the switching element. That is, the control IC outputs a PWM (Pulse Width Modulation) signal to the switching element. The control IC drives the switching element and controls the current supplied to the electric motor 60 based on instructions from the outside (for example, a processor mounted on a circuit board mounted on the electronic device 90) or the output of a rotation sensor provided in the electric motor 60.

[0022] 2A, the circuit board 70 is located between the central base portion 42 of the base plate 40 and the electric motor 60. The circuit board 70 has an opening 70a in its center. The motor support portion 52 and the rotation shaft 63 are disposed inside the opening 70a. The circuit board 70 may be attached to the motor support portion 52.

[0023] The component 71 mounted on the circuit board 70 may include, in addition to the control IC, a protection element for stabilizing the power supply voltage of the electric motor 60. An example of the protection element of the component 71 may be a protection diode disposed between the power supply and ground and connected in series therewith. For example, the protection diode may be connected in parallel with the control IC and the electric motor 60 to prevent excessive voltage from being applied to them. Another example of the protection element of the component 71 may be a protection capacitor disposed between the power supply and ground and connected in series therewith. For example, the protection capacitor may be connected in parallel with the control IC and the electric motor to maintain a constant voltage applied to them. The component 71 may also include a resistor, i.e., a shunt resistor, for measuring the current supplied to the electric motor 60. For example, the shunt resistor may be connected between the switching element and ground.

[0024] [Peripheral wall] 2A, air F1 and F2 pass between the central base portion 42 and the peripheral base portion 41 of the base plate 40 and are introduced toward the impeller 20. When the cooling fan 10 is mounted on the electronic device 90, the upper side of the cooling fan 10 may be covered with an exterior member (an exterior panel 92, described below) of the electronic device 90. In this case, the air passes through a gap G1 between the underside of the exterior panel 92 and a housing 91a (see FIG. 2A) that houses the cooling fan 10, and further passes through the gap between the central base portion 42 and the peripheral base portion 41, and is introduced toward the impeller 20.

[0025] With conventional cooling fans, components and dust contained in the air can adhere to components 71 on the circuit board. In contrast, cooling fan 10 has a peripheral wall 55 that surrounds circuit board 70, as shown in Figures 2A and 2B. Peripheral wall 55 stands along the outer periphery of circuit board 70. Peripheral wall 55 reduces the amount of components and the like in the air that adhere to components 71 on circuit board 70.

[0026] 2B, the peripheral wall portion 55 has a lower end 55a and an upper end 55b. The position of the circuit board 70 in the axial direction (vertical direction) may be below (on the first side) the central base portion 42 and above (on the second side) the lower end 55a of the peripheral wall portion 55. This makes it possible to more effectively reduce the amount of components in the air that adhere to the components 71 on the circuit board 70.

[0027] The central base portion 42 has a flange portion 42a on the outer periphery base portion 41 side and an inner portion 42b of the flange portion 42a. The flange portion 42a forms the outer periphery of the central base portion 42 and is adjacent to the gap between the central base portion 42 and the outer periphery base portion 41. A peripheral wall portion 55 is provided on the outer periphery of the central base portion 42. An upper end 55b of the peripheral wall portion 55 is located below the flange portion 42a and surrounds the inner portion 42b of the flange portion 42a of the central base portion 42. This structure effectively prevents air from passing between the central base portion 42 and the upper end 55b.

[0028] [Fixing the peripheral wall] An upper end 55b of the peripheral wall portion 55 may be in contact with the central base portion 42. The upper end 55b may or may not be fixed to the central base portion 42.

[0029] The peripheral wall portion 55 may be molded integrally with the support portion 50. The peripheral wall portion 55 may be connected to the fixing portion 51 through a plurality of through holes formed in the central base portion 42. In this case, the peripheral wall portion 55 is molded from resin.

[0030] Alternatively, the peripheral wall portion 55 may be a component formed separately from the support portion 50. In this case, the peripheral wall portion 55 may be attached to the central base portion 42 with fasteners such as screws or with an adhesive, for example. The peripheral wall portion 55 may be attached to the outer periphery of the circuit board 70 instead of the central base portion 42. For example, the peripheral wall portion 55 may be bonded to the outer periphery of the circuit board 70. The peripheral wall portion 55 may be a component molded from resin, or may be a component formed from metal.

[0031] [Shape and layout of the surrounding wall] 3A, the peripheral wall 55 may surround the entire outer periphery of the circuit board 70. This more effectively prevents components contained in the air from adhering to components on the circuit board. The peripheral wall 55 may have a shape that matches the outer periphery of the circuit board 70. For example, the circuit board 70 may be circular, and the peripheral wall 55 may be annular.

[0032] Alternatively, the peripheral wall 55 may surround only a portion of the outer periphery of the circuit board 70, as shown in Figures 3B and 3C. For example, as shown in Figure 3B, the peripheral wall 55 may surround more than half of the outer periphery of the circuit board 70 (a range of less than 360 degrees and more than 180 degrees). 3 As shown by C, the peripheral wall portion 55 may surround less than half the outer periphery of the circuit board 70 and more than one-quarter of the outer periphery (more than 90 degrees and less than 180 degrees).

[0033] figure 3 B and Fig. 3 When peripheral wall portion 55 surrounds only a portion of the outer periphery of circuit board 70 as shown by C, peripheral wall portion 55 may be formed on the side of the outer periphery of circuit board 70 that faces the intake ports Sa and Sb (see FIG. 4A) of electronic device 90. In other words, peripheral wall portion 55 is preferably located between the intake ports Sa and Sb of electronic device 90 and circuit board 70.

[0034] As shown in FIG. 2B , the central base portion 42 is located higher than the outer peripheral base portion 41. That is, the position of the central base portion 42 in the axial direction is shifted toward the opposite side of the impeller 20 (the second side, or upper side in FIG. 2B ) from the position of the outer peripheral base portion 41. This shape of the base plate 40 allows the size of the air intake between the outer peripheral edge of the central base portion 42 and the inner peripheral edge of the outer peripheral base portion 41 to be increased. As a result, the amount of air introduced toward the impeller 20 by driving the cooling fan 10 can be increased. Furthermore, because the positions of the motor housing 30 and the electric motor 60 can be shifted upward in the axial direction, the amount of air introduced from below the impeller 20 can also be increased. Furthermore, because the central base portion 42 is located higher than the outer peripheral base portion 41, it is easy to increase the size of the peripheral wall portion 55 in the axial direction.

[0035] The peripheral wall portion 55 extends downward (toward the first side in the axial direction) from the central base portion 42. As shown in FIG. 2B , the axial position of at least a portion of the peripheral wall portion 55 is between the central base portion 42 and the outer peripheral base portion 41. The axial position of at least the upper portion of the peripheral wall portion 55 corresponds to the axial gap G3 between the central base portion 42 and the outer peripheral base portion 41. This makes it possible to more effectively reduce the amount of airborne components adhering to the components 71 on the circuit board 70.

[0036] As shown in FIG. 2B , the lower end 55a of the peripheral wall portion 55 may be located below the peripheral base portion 41 (on the first side in the axial direction). This makes it possible to more effectively reduce the amount of airborne components adhering to the components 71 on the circuit board 70. In particular, in the example shown in FIG. 2B , the lower end 55a extends downward beyond the position of the lower surface 41c of the peripheral base portion 41 in the axial direction. Unlike the example shown in the figure, the lower end 55a may be located at substantially the same height as the peripheral base portion 41. On the other hand, the circuit board 70 may be located above the peripheral base portion 41 or at substantially the same height as the peripheral base portion 41.

[0037] [Component placement on the circuit board] The upper surface 70b of the circuit board 70 faces the central base portion 42. As shown in FIG. 2B , a gap is provided between the upper surface 70b and the central base portion 42. A plurality of components 71 for driving the electric motor 60 may be disposed on the upper surface 70b. This makes it possible to more effectively reduce the amount of components in the air that adhere to the components 71 on the circuit board 70.

[0038] 2B, the position of the circuit board 70 in the axial direction is located below the midpoint M7 between the positions of the central base portion 42 and the peripheral base portion 41. This ensures a sufficient gap between the top surface 70b and the central base portion 42, making it easy to mount large components on the top surface 70b.

[0039] The main components of the components 71 that drive the electric motor 60 may be arranged on the upper surface 70b. As described above, the components 71 that drive the electric motor 60 include a switching element that controls the current supplied to the electric motor 60, a control IC that controls the switching element, protection elements (protection diodes, protection capacitors) for stabilizing the power supply voltage, and a resistor for measuring the current supplied to the electric motor 60. All of these may be arranged on the upper surface 70b. This makes it possible to effectively suppress the effect of adhesion of components in the air on the operation of the electric motor 60.

[0040] Alternatively, the control IC or switching element, which is the most important element among the above-described multiple components 71, may be mounted on the upper surface 70b. As yet another example, the control IC and the switching element may be disposed on the upper surface 70b. This effectively reduces the effect of adhesion of components in the air on the operation of the electric motor 60.

[0041] [Positional relationship between peripheral wall and parts] When components 71 are mounted on the upper surface 70b of the circuit board 70 in this manner, the peripheral wall 55 may surround only a portion of the outer periphery of the circuit board 70, as shown in Figures 3B and 3C. This provides a vent (a portion where the peripheral wall 55 is not formed) in the space between the central base 42 and the circuit board 70, making it easier to ensure cooling performance for the components 71. Such a vent may be provided on the opposite side of the line L1 that passes through the axis C1 of the cooling fan 10 and is perpendicular to the axis C1 from the intake ports Sa and Sb of the electronic device 90 (see Figure 4A).

[0042] The arrangement of components 71 is not limited to the example described here. For example, components that generate a large amount of heat among components 71 may be arranged on the lower surface 70c of circuit board 70. For example, switching elements may be arranged on the lower surface 70c of circuit board 70. This ensures cooling performance for components 71 that need to be cooled more.

[0043] The peripheral wall portion 55 extends downward from the central base portion 42. The position of a lower end 55a of the peripheral wall portion 55 in the axial direction may be lower than a component 71 arranged on the circuit board 70. For example, if a component 71 is arranged on the lower surface 70c of the circuit board 70, the position of the lower end 55a may be lower than this component 71.

[0044] Component 71 that drives electric motor 60 may be disposed on the opposite side of straight line L1 (see FIGS. 3B and 3C) from air intakes Sa and Sb (see FIG. 4A) of electronic device 90. Such an arrangement of component 71 may be adopted when peripheral wall 55 surrounds only a portion of the outer periphery of circuit board 70 or when component 71 is disposed on bottom surface 70c of circuit board 70.

[0045] The components 71 that drive the electric motor 60 specifically include the above-mentioned switching elements, control ICs, protection elements (protection diodes, protection capacitors), and resistors for measuring the current supplied to the electric motor 60. These may be arranged on the opposite side of the line L1 (see FIGS. 3B and 3C) from the air intakes Sa and Sb of the electronic device 90. In other words, all of the main components may be arranged on the side of the line L1 that faces the air vent formed between the central base portion 42 and the circuit board 70 (the portion where the peripheral wall portion 55 is not formed).

[0046] Alternatively, the control IC and / or switching elements, which are components essential for driving the electric motor 60, may be arranged on the opposite side of the line L1 from the intake ports Sa and Sb of the electronic device 90. In other words, the control IC and / or switching elements may be arranged on the side of the line L1 that faces the ventilation port (the portion where the peripheral wall 55 is not formed) formed between the central base portion 42 and the circuit board 70. This ensures cooling performance for these components, while the peripheral wall 55 can prevent components in the air from adhering to these components.

[0047] 3A to 3C, a plurality of cables 72 are connected to the circuit board 70. A connector 73 to which the cables 72 are connected may be mounted on the circuit board 70. The cables 72 include a cable for supplying a drive current to the electric motor 60. The plurality of cables 72 also includes a cable for supplying a control signal related to the drive of the electric motor 60 to a control IC from an external device (for example, a processor mounted on the electronic device 90).

[0048] The cable 72 may extend from the circuit board 70 beyond the lower end 55a of the peripheral wall portion 55 toward the outside in the radial direction of the circular circuit board 70. In this case, the connector 73 may be disposed on the lower surface 70c (see FIG. 2B) of the circuit board 70. As shown in FIGS. 3B and 3C, if the peripheral wall portion 55 surrounds only a portion of the outer periphery of the circuit board 70, the cable 72 may pass through the portion where the peripheral wall portion 55 is not formed and extend toward the outside in the radial direction of the circuit board 70. In this case, the connector 73 may be disposed on either the upper surface 70b (see FIG. 2B) or the lower surface 70c (see FIG. 2B) of the circuit board 70.

[0049] [Electronic equipment] The electronic device 90 will now be described. The electronic device 90 is, for example, an entertainment device that functions as a game device or audio-visual device. The electronic device 90 outputs moving image data generated by executing a game program, video and audio data acquired through a network, and video and audio data acquired from a recording medium such as an optical disc to a display device such as a television. The electronic device may also be a personal computer or a server computer.

[0050] As shown in FIG. 4A, electronic device 90 has device main body 91. Device main body 91 has housing 91a. Housing 91a houses the above-mentioned cooling fan 10. Housing 91a also houses a circuit board on which various electronic components such as a CPU and a GPU are mounted. Housing 91a has a heat sink (heat pipe, etc.). The heat sink is connected to the electronic components such as the CPU. Cooling fan 10 introduces external air into housing 91a and forms an airflow that passes through the heat sink.

[0051] 4B, the electronic device 90 has an upper exterior panel 92 that covers an upper surface 91b of the device body 91 and is attached to the upper surface 91b. The electronic device 90 also has a lower exterior panel 93 that covers a lower surface of the device body 91 and is attached to the lower surface.

[0052] [Air intake system for electronic devices] An air intake 91e (see Figures 2A and 4B) is formed in the upper surface 91b of the housing 91a (hereinafter, this air intake 91e will be referred to as the "upper housing air intake"). The cooling fan 10 is arranged so that an axis C1 passing through its center of rotation faces the vertical direction of the electronic device 90. The cooling fan 10 is located below the upper housing air intake 91e. An air intake 91f (see Figure 2A) may also be formed in the lower surface of the housing 91a (hereinafter, this air intake 91f will be referred to as the "lower housing air intake").

[0053] As shown in FIG. 4A, the exterior components of the electronic device 90 (i.e., the upper exterior panel 92, the lower exterior panel 93, and the housing 91a) have air intakes Sa·Sb·Sc·Sd for introducing outside air into the interior of the electronic device 90.

[0054] The air intakes Sa and Sb are formed, for example, between an edge of the upper exterior panel 92 and an edge of the upper surface 91b of the housing 91a. The air intakes Sa and Sb open in a direction intersecting with the axis C1. For example, as shown in FIG. 4A, the air intake Sa may open toward the front side of the electronic device 90, and the air intake Sb may open toward the right side of the electronic device 90. The air intakes Sc and Sd are formed, for example, between an edge of the lower exterior panel 93 and an edge of the lower surface of the housing 91a. The air intakes Sc and Sd open in a direction intersecting with the axis C1. For example, as shown in FIG. 4A, the air intake Sc may open toward the front side of the electronic device 90, and the air intake Sd may open toward the right side of the electronic device 90.

[0055] A gap G1 (see FIG. 2A) is formed between the upper surface 91b of the housing 91a and the upper exterior panel 92. This gap G1 functions as an air flow path from the intake ports Sa and Sb to the upper housing intake port 91e (hereinafter, this gap G1 will be referred to as the upper air intake path). Furthermore, a gap G2 is formed between the lower surface of the housing 91a and the lower exterior panel 93. This gap G2 functions as an air flow path from the intake ports Sc and Sd to the lower housing intake port 91f, which is formed below the cooling fan 10 (hereinafter, this gap G2 will be referred to as the lower air intake path).

[0056] When cooling fan 10 is driven, air is introduced into upper air intake passage G1 from upper air intake ports Sa and Sb. This air flows through upper air intake passage G1 in a direction intersecting (substantially perpendicular to) axis C1 of cooling fan 10, and is introduced into housing 91a (inside cooling fan 10) through upper housing air intake port 91e. Peripheral wall 55 prevents components in this air from adhering to components 71 on circuit board 70.

[0057] Furthermore, when the cooling fan 10 is driven, air is introduced into the lower air intake passage G2 from the lower air intake ports Sc and Sd. This air flows through the lower air intake passage G2 in a direction intersecting (substantially perpendicular to) the axis C1 of the cooling fan 10, and is introduced into the housing 91a (inside the cooling fan 10) from the lower housing air intake port 91f.

[0058] [summary] (1) The cooling fan proposed in this disclosure has a base plate including an annular outer base portion having a mounting portion and a central base portion located inside the outer base portion. The cooling fan also includes an electric motor located on a first axial side (lower in FIG. 2A, etc.) of the central base portion, an impeller located radially outward of the electric motor and rotated by the electric motor, a circuit board for driving the electric motor located between the electric motor and the central base portion, and a peripheral wall portion surrounding the outer periphery of the circuit board. This cooling fan allows the peripheral wall portion to reduce the amount of airborne components and dust that adhere to components on the circuit board. (2) In the structure of (1), the position of the central base portion in the axial direction is closer to the second side in the axial direction (in the example shown in FIG. 2A, etc.) than the position of the peripheral base portion in the axial direction. Upward ) The base plate may be offset to the left or right. This shape of the base plate makes it possible to increase the amount of air introduced into the impeller side when the cooling fan is driven. (3) In the structure of (2), the axial position of at least a portion of the peripheral wall (the upper portion in the example shown in FIG. 2A etc.) may be between the positions of the central base and the peripheral base in the axial direction. With this cooling fan, the peripheral wall can more effectively reduce the amount of airborne components and dust that adhere to components on the circuit board. (4) In the structure of (2) or (3), the peripheral wall portion extends from the central base portion toward a first side in the axial direction (downward in the example shown in FIG. 2A, etc.), and the end of the peripheral wall portion may be located closer to the first side in the axial direction than the position of the outer peripheral base portion. With this cooling fan, the peripheral wall portion can more effectively reduce the amount of airborne components and dust that adhere to components on the circuit board. (5) In the structure of (4), the circuit board may be located on the second axial side (upper in the example shown in FIG. 2A, etc.) of the end of the peripheral wall (lower end 55a in the example shown in FIG. 2A, etc.). With this cooling fan, the peripheral wall can more effectively reduce the amount of airborne components and dust that adhere to the components on the circuit board. (6)(1) to (5) Any one of In the structure of (a), the circuit board may have a surface facing the central base portion, and multiple components may be arranged on the surface of the circuit board. With this cooling fan, the peripheral wall portion can further effectively reduce the amount of airborne components and dust that adhere to the multiple components on the circuit board. (7)(1) to (6) Any one of In the structure of (a), the peripheral wall is provided on the outer periphery of the central base, which prevents air from passing between the central base and the peripheral wall, while ensuring a sufficient size for the circuit board. (8)(1) to (7) Any one ofIn this structure, a gap is provided between the outer periphery of the central base portion and the inner periphery of the outer periphery base portion, ensuring an air flow path between the outer periphery of the central base portion and the inner periphery of the outer periphery base portion. (9) The electronic device proposed in this disclosure includes a cooling fan having the structure described in (1) to (8) and a housing that houses the cooling fan. The peripheral wall of this electronic device can reduce the amount of airborne components and dust that adhere to components on the circuit board.

[0059] The cooling fan proposed in this disclosure is not limited to the above-described cooling fan 10, and may be modified in various ways. Furthermore, the electronic device proposed in this disclosure is not limited to the above-described electronic device 90, and may be modified in various ways.

Claims

1. a base plate having an annular outer peripheral base portion and a central base portion located inside the outer peripheral base portion; an electric motor having a rotation shaft and located on a first side in the axial direction relative to the central base portion; an impeller positioned radially outward of the electric motor and rotated by being driven by the electric motor; a circuit board for driving the electric motor, the circuit board being located between the electric motor and the central base portion; a peripheral wall portion surrounding the outer periphery of the circuit board, a flow of air introduced toward the impeller is formed between the central base portion and the outer peripheral base portion of the base plate; The central base portion is positioned on a second side in the axial direction, which is opposite to the first side in the axial direction, relative to the outer circumferential base portion. It has a cooling fan.

2. a position of at least a portion of the peripheral wall portion in the axial direction between a position of the central base portion and a position of the outer peripheral base portion in the axial direction; The cooling fan according to claim 1 .

3. The peripheral wall portion extends from the central base portion toward the first side in the axial direction, and an end of the peripheral wall portion is located closer to the first side in the axial direction than the position of the outer peripheral base portion. The cooling fan according to claim 1 .

4. The circuit board is located closer to the second side in the axial direction than the end of the peripheral wall portion. The cooling fan according to claim 3.

5. the circuit board has a surface facing the central base portion; A plurality of components are arranged on the surface of the circuit board. The cooling fan according to claim 1 .

6. The peripheral wall portion is provided on the outer periphery of the central base portion. The cooling fan according to claim 1 .

7. A gap is provided between the outer periphery of the central base portion and the inner periphery of the outer periphery base portion. The cooling fan according to claim 1 .

8. The cooling fan according to claim 1; a housing that accommodates the cooling fan; An electronic device having:

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