Cooling fan and electronic device

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 Art

[0002] Inside electronic devices such as game devices, personal computers, and server computers, cooling fans are arranged to cool heat-generating components such as CPUs (Central Processing Units) and GPUs (Graphics Processing Units) mounted on circuit boards. An air intake for introducing external air is formed in the exterior member of the electronic device. Patent Document 1 below discloses an example of such an electronic device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The cooling fan has a circuit board on which various electronic components such as a switching element (FET) that controls the current supplied to the motor and a control IC that controls the switching element according to a signal input from the outside are mounted. Depending on the relative position between the air intake formed in the exterior member of the electronic device and the cooling fan, and the usage environment of the electronic device, components and dust contained in the air introduced from the air intake may adhere to the electronic components on the circuit board.

Means for Solving the Problems

[0005] The cooling fan proposed in the present disclosure includes a base plate having an annular outer peripheral base portion and a central base portion located inside the outer peripheral base portion, a motor having a rotation axis and located on a first side in the axial direction with respect to the central base portion, an impeller located radially outside the motor and rotated by driving of the motor, a circuit board located between the motor and the central base portion for driving the motor, and a peripheral wall portion surrounding an 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 components and dust in the air adhering to components on the circuit board can be reduced by the peripheral wall portion.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2A

Figure 2B

Figure 3A

Figure 3B

Figure 3C

Figure 4A

Figure 4B

Mode for Carrying Out the Invention

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

[0010] Hereinafter, in FIGS. 1 etc., the Z1 direction and the Z2 direction shown are referred to as the upward direction and the downward direction, respectively. Also, in FIG. 4A showing the electronic device 90, the X1 direction and the X2 direction are referred to as the rightward direction and the leftward direction, respectively, and the Y1 direction and the Y2 direction are referred to as the forward direction and the backward direction, respectively. These directions are defined to explain the shapes of the elements (parts, members, and portions) of the cooling fan 10 and the electronic device 90 and their relative positional relationships. Therefore, the directions shown in the drawings do not limit the postures of the cooling fan 10 and the electronic device 90 during use.

[0011] [Impeller and Motor Housing] As shown in FIG. 1, the cooling fan 10 has an impeller 20. The impeller 20 is rotatable about an axis C1 along the vertical direction. The impeller 20 has a plurality of fins 21 arranged in its rotation 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 disposed on the outer periphery of the stator 62. Further, the cooling fan 10 has a motor housing 30 that houses the electric motor 60 at its central portion. 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 peripheral 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 the electric motor 60 is driven. The impeller 20 and the motor housing 30 may be integrally molded by 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 outside the electric motor 60 and / or the rotating shaft 63 with respect to the electric motor 60. The fins 21 of the impeller 20 extend radially outward from the outer peripheral surface of the motor housing 30. As shown in FIG. 2A, when the impeller 20 rotates, the air F1, F2, F3, F4 is introduced into the impeller 20 from above and below the impeller 20 and is sent out radially outside 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 extending direction (for example, the vertical direction; hereinafter referred to as the axial direction) of the rotating shaft 63 of the electric motor 60. When the cooling fan 10 is mounted on the electronic device 90, it may be arranged in a posture where the base plate 40 is located above the impeller 20, or conversely, it may be arranged in a posture where the base plate 40 is located below the impeller 20.

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

[0016] As shown in FIG. 1, the base plate 40 has a central base portion 42 located inside the outer peripheral base portion 41. A gap is formed between the inner peripheral edge of the outer peripheral base portion 41 and the outer peripheral edge of the central base portion 42. Further, the base plate 40 has a plurality of connecting portions 43 that connect the outer peripheral base portion 41 and the central base portion 42. The plurality of connecting portions 43 are arranged 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. Further, the base plate 40 may have an annular guard portion 44 located between the outer peripheral base portion 41 and the central base portion 42. According to the connecting portions 43 and the guard portion 44, the gap (air inlet) formed between the outer peripheral base portion 41 and the central base portion 42 can be partitioned into a plurality of regions. Different from the example shown in FIG. 1, the base plate 40 may not have the guard portion 44.

[0017] [Support Structure of Electric Motor] As shown in FIG. 2A, the electric motor 60 is located on one side (the first side, the lower side in FIG. 2A) in the axial direction with respect to the central base portion 42 of the base plate 40. Further, a support portion 50 is formed on the base plate 40. The support portion 50 has a fixing portion 51 and a motor support portion 52. The fixing portion 51 is formed, for example, on the upper surface of the central base portion 42. The motor support portion 52 extends from the central base portion 42 toward one side in the axial direction (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 formed of, for example, resin. The fixing portion 51 and the motor support portion 52 may be connected to each other through, for example, one or a plurality of holes penetrating 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 disposed inside a mold for forming the support portion 50, resin may be supplied into the mold, and the support portion 50 may be formed by the resin.

[0019] The motor support portion 52 may be formed in a cylindrical shape. As shown in FIG. 2A, the rotation shaft 63 of the electric motor 60 may be disposed inside the motor support portion 52. And the rotation shaft 63 may be supported inside the motor support portion 52 via a bearing. This rotation shaft 63 is connected to the motor housing 30 and can rotate integrally with the motor housing 30.

[0020] [Circuit board] As shown in FIG. 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. As the switching element, for example, a MOSFET (metal-oxide-semiconductor field-effect transistor) can be used.

[0021] The control IC outputs an on / off signal of 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 based on an instruction 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, and controls the current supplied to the electric motor 60.

[0022] As shown in FIG. 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 at its central portion. Inside the opening 70a, the motor support portion 52 and the rotating shaft 63 are arranged. The circuit board 70 may be attached to the motor support portion 52.

[0023] The components 71 mounted on the circuit board 70 may include, in addition to a control IC or the like, a protection element for stabilizing the power supply voltage of the electric motor 60. The component 71 may have, as an example of the protection element, a protection diode disposed between the power supply and the ground and connected in series therewith. This protection diode is connected in parallel with, for example, the control IC and the electric motor 60 to prevent an excessive voltage from being applied thereto. Further, the component 71 may have, as an example of the protection element, a protection capacitor disposed between the power supply and the ground and connected in series therewith. The protection capacitor is connected in parallel with, for example, the control IC and the electric motor to keep the voltage applied thereto constant. Further, the component 71 may include a resistor for measuring the current supplied to the electric motor 60, that is, a shunt resistor. The shunt resistor may be connected to, for example, the switching element and the ground.

[0024] [Peripheral wall portion] As shown in FIG. 2A, the air F1 and F2 passes between the central base portion 42 and the outer peripheral base portion 41 of the base plate 40 and is 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 (exterior panel 92 described later) of the electronic device 90. In this case, the air passes through the gap G1 between the lower surface of the exterior panel 92 and the 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 outer peripheral base portion 41 and is introduced toward the impeller 20.

[0025] In a conventional cooling fan, components and dust contained in this air may adhere to the components on the circuit board. In contrast, as shown in FIGS. 2A and 2B, the cooling fan 10 has a peripheral wall portion 55 that surrounds the circuit board 70. The peripheral wall portion 55 stands along the outer peripheral edge of the circuit board 70. By this peripheral wall portion 55, the amount of components in the air adhering to the components 71 on the circuit board 70 can be reduced.

[0026] As shown in FIG. 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 the central base portion 42 (the first side) and above the lower end 55a of the peripheral wall portion 55 (the second side). According to this, the amount of components in the air adhering to the components 71 on the circuit board 70 can be more effectively reduced.

[0027] The central base portion 42 has a flange portion 42a on the outer peripheral base portion 41 side and a portion 42b inside the flange portion 42a. The flange portion 42a constitutes the outer peripheral edge of the central base portion 42 and is adjacent to the gap between the central base portion 42 and the outer peripheral base portion 41. The peripheral wall portion 55 is provided on the outer peripheral edge of the central base portion 42. The upper end 55b of the peripheral wall portion 55 is located below the flange portion 42a and surrounds the portion 42b inside the flange portion 42a of the central base portion 42. According to this structure, it is possible to effectively suppress air from passing between the central base portion 42 and the upper end 55b.

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

[0029] The peripheral wall portion 55 may be integrally formed with the support portion 50, for example. 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 formed of 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 by a fixture such as a screw or an adhesive, for example. The peripheral wall portion 55 may be attached to the outer peripheral edge of the circuit board 70 instead of the central base portion 42. For example, the peripheral wall portion 55 may be adhered to the outer peripheral edge of the circuit board 70. The peripheral wall portion 55 may be a component formed of resin or a component formed of metal.

[0031] [Shape and Arrangement of the Peripheral Wall Portion] As shown in FIG. 3A, the peripheral wall portion 55 may surround the entire outer peripheral edge of the circuit board 70. According to this, it is possible to more effectively suppress components contained in the air from adhering to the components on the circuit board. The peripheral wall portion 55 may have a shape that conforms to the outer peripheral edge of the circuit board 70. For example, the circuit board 70 may be circular, and the peripheral wall portion 55 may be annular.

[0032] In contrast, as shown in FIGS. 3B and 3C, the peripheral wall portion 55 may surround only a part of the outer peripheral edge of the circuit board 70. For example, as shown in FIG. 3B, the peripheral wall portion 55 may surround a range of more than half of the outer peripheral edge of the circuit board 70 (less than 360 degrees and more than 180 degrees). As another example, as shown in FIG. 3 C, the peripheral wall portion 55 may surround a range less than half of the outer peripheral edge of the circuit board 70 and more than 1 / 4 of the outer peripheral edge (more than 90 degrees and less than 180 degrees).

[0033] FIG. 3 B and FIG. 3 C, when the peripheral wall portion 55 surrounds only a part of the outer peripheral edge of the circuit board 70, the peripheral wall portion 55 may be formed on the side of the outer peripheral edge of the circuit board 70 facing the air inlets Sa and Sb (see FIG. 4A) of the electronic device 90. That is, it is preferable that the peripheral wall portion 55 is located between the air inlets Sa and Sb of the electronic device 90 and the circuit board 70.

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

[0035] The peripheral wall portion 55 extends downward (the first side in the axial direction) from the central base portion 42. As shown in FIG. 2B, at least a part of the peripheral wall portion 55 in the axial direction is between the central base portion 42 and the outer peripheral base portion 41 in the axial direction. At least the upper position of the peripheral wall portion 55 in the axial direction corresponds to the gap G3 in the axial direction between the central base portion 42 and the outer peripheral base portion 41. Thereby, the amount of components and the like in the air adhering to the components 71 on the circuit board 70 can be more effectively reduced.

[0036] As shown in FIG. 2B, the lower end 55a of the peripheral wall portion 55 may be located below (the first side in the axial direction) the outer peripheral base portion 41. Thereby, the amount of components and the like in the air adhering to the components 71 on the circuit board 70 can be more effectively reduced. In particular, in the example shown in FIG. 2B, the lower end 55a exceeds the position of the lower surface 41c of the outer peripheral base portion 41 in the axial direction downward. Different from the example shown in the figure, the lower end 55a may be located substantially at the same height as the outer peripheral base portion 41. On the other hand, the circuit board 70 may be located above the outer peripheral base portion 41 or substantially at the same height as the outer peripheral base portion 41.

[0037] [Arrangement of Components on 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 secured between the upper surface 70b and the central base portion 42. A plurality of components 71 for driving the electric motor 60 may be arranged on the upper surface 70b. According to this, the amount of components in the air adhering to the components 71 on the circuit board 70 can be more effectively reduced.

[0038] As shown in FIG. 2B, the position of the circuit board 70 in the axial direction is located below the intermediate position M7 between the position of the central base portion 42 and the position of the outer peripheral base portion 41 in the axial direction. According to this, a sufficient gap is secured between the upper surface 70b and the central base portion 42, and it becomes easy to mount a large-sized component on the upper surface 70b.

[0039] On the upper surface 70b, the main components among the components 71 for driving the electric motor 60 may be arranged. As the components 71 for driving the electric motor 60, as described above, there are a switching element that controls the current supplied to the electric motor 60, a control IC that controls the switching element, a protection element (protection diode, protection capacitor) 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. According to this, the influence of the adhesion of components in the air and the like on the driving of the electric motor 60 can be effectively suppressed.

[0040] Differently, the control IC or the switching element, which is the most main element among the plurality of components 71 described above, may be mounted on the upper surface 70b. As another example, the control IC and the switching element may be arranged on the upper surface 70b. According to this, the influence of the adhesion of components in the air and the like on the driving of the electric motor 60 can be effectively reduced.

[0041] [Position relationship between the peripheral wall portion and the components] When components 71 are mounted on the upper surface 70b of the circuit board 70 in this way, the peripheral wall portion 55 may surround only a part of the outer peripheral edge of the circuit board 70 as shown in FIGS. 3B and 3C. By doing so, a ventilation port (a portion where the peripheral wall portion 55 is not formed) is provided in the space between the central base portion 42 and the circuit board 70, making it easier to ensure the cooling performance for the components 71. Such a ventilation port may be secured on the side opposite to the air inlets Sa·Sb (see FIG. 4A) of the electronic device 90 across a straight line L1 passing through the axis C1 of the cooling fan 10 and orthogonal to the axis C1.

[0042] The arrangement of the components 71 is not limited to the example described here. For example, components with a large heat generation amount among the components 71 may be arranged on the lower surface 70c of the circuit board 70. For example, the switching element may be arranged on the lower surface 70c of the circuit board 70. By doing so, it is also possible to ensure the cooling performance for the 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 the lower end 55a of the peripheral wall portion 55 in the axial direction may be below the components 71 arranged on the circuit board 70. For example, when components 71 are arranged on the lower surface 70c of the circuit board 70, the position of the lower end 55a may be below these components 71.

[0044] The components 71 that drive the electric motor 60 may be arranged on the side opposite to the air inlets Sa·Sb (see FIG. 4A) of the electronic device 90 across the straight line L1 (see FIGS. 3B and 3C). Such an arrangement of the components 71 may be adopted when the peripheral wall portion 55 surrounds only a part of the outer peripheral edge of the circuit board 70 or when the components 71 are arranged on the lower surface 70c of the circuit board 70.

[0045] The components 71 for driving the electric motor 60 specifically include the above-described switching element, control IC, protection elements (protection diodes, protection capacitors), and a resistor for measuring the current supplied to the electric motor 60. These may be arranged on the side opposite to the air inlets Sa and Sb of the electronic device 90 with the straight line L1 (see FIGS. 3B and 3C) interposed therebetween. In other words, all of the main components may be arranged on the side of the ventilation opening (the portion where the peripheral wall portion 55 is not formed) formed between the central base portion 42 and the circuit board 70 with respect to the straight line L1.

[0046] In contrast, the control IC and / or the switching element, which are essential components for driving the electric motor 60, may be arranged on the side opposite to the air inlets Sa and Sb of the electronic device 90 with the straight line L1 interposed therebetween. In other words, the control IC and / or the switching element may be arranged on the side of the ventilation opening (the portion where the peripheral wall portion 55 is not formed) formed between the central base portion 42 and the circuit board 70 with respect to the straight line L1. According to this, while ensuring the cooling performance for these components, it is possible to suppress the adhesion of components in the air and the like to these components by the peripheral wall portion 55.

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

[0048] The cable 72 may extend from the circuit board 70 beyond the lower end 55a of the peripheral wall portion 55 and 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, when the peripheral wall portion 55 surrounds only a part of the outer peripheral edge 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 the upper surface 70b (see FIG. 2B) of the circuit board 70 or on the lower surface 70c (see FIG. 2B) of the circuit board 70.

[0049] [Electronic device] The electronic device 90 will be described. The electronic device 90 is, for example, an entertainment device that functions as a game device or an 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 disk to a display device such as a television. The electronic device may be a personal computer or a server computer.

[0050] As shown in FIG. 4A, the electronic device 90 has a device main body 91. The device main body 91 has a housing 91a. The housing 91a houses the cooling fan 10 described above. Further, the housing 91a houses a circuit board on which various electronic components such as a CPU and a GPU are mounted. The housing 91a has a radiator (such as a heat sink or a heat pipe). The radiator is connected to electronic components such as the CPU. The cooling fan 10 introduces external air into the housing 91a and forms an air flow passing through the radiator.

[0051] As shown in FIG. 4B, the electronic device 90 has an upper exterior panel 92 that covers the upper surface 91b of the device main body 91 and is attached to the upper surface 91b. Further, the electronic device 90 has a lower exterior panel 93 that covers the lower surface of the device main body 91 and is attached to the lower surface.

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

[0053] The exterior members of the electronic device 90 (i.e., the upper exterior panel 92, the lower exterior panel 93, and the housing 91a) have air intake ports Sa, Sb, Sc, and Sd for introducing external air into the interior of the electronic device 90 as shown in FIG. 4A.

[0054] The air intake ports Sa and Sb are formed, for example, between the edge of the upper exterior panel 92 and the edge of the upper surface 91b of the housing 91a. The air intake ports Sa and Sb open in a direction intersecting the axis C1. For example, as shown in FIG. 4A, the air intake port Sa may open toward the front side of the electronic device 90, and the air intake port Sb may open toward the right side of the electronic device 90. The air intake ports Sc and Sd are formed, for example, between the edge of the lower exterior panel 93 and the edge of the lower surface of the housing 91a. The air intake ports Sc and Sd open in a direction intersecting the axis C1. For example, as shown in FIG. 4A, the air intake port Sc may open toward the front side of the electronic device 90, and the air intake port 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 air inlets Sa and Sb to the upper housing air inlet 91e. (Hereinafter, this gap G1 is referred to as the upper intake path.) Also, 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 air inlets Sc and Sd to the lower housing air inlet 91f formed below the cooling fan 10. (Hereinafter, this gap G2 is referred to as the lower intake path.)

[0056] When the cooling fan 10 is driven, air is introduced from the upper air inlets Sa and Sb into the upper intake path G1. This air flows through the upper intake path G1 in a direction intersecting (substantially orthogonal) to the axis C1 of the cooling fan 10, and is introduced into the housing 91a (inside the cooling fan 10) from the upper housing air inlet 91e. The adhesion of components in this air to the components 71 on the circuit board 70 can be suppressed by the peripheral wall portion 55.

[0057] Also, when the cooling fan 10 is driven, air is introduced from the lower air inlets Sc and Sd into the lower intake path G2. This air flows through the lower intake path G2 in a direction intersecting (substantially orthogonal) 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 inlet 91f.

[0058] [Summary] (1) The cooling fan proposed in the present disclosure has a base plate having an annular outer peripheral base portion with an attachment portion and a central base portion located inside the outer peripheral base portion. Also, the cooling fan has an electric motor located on the first side (downward in FIG. 2A etc.) in the axial direction with respect to the central base portion, an impeller located radially outside the electric motor and rotated by the drive of 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. According to this cooling fan, the amount of components and dust in the air adhering to the components on the circuit board can be reduced by the peripheral wall portion. (2) In the structure of (1), the position of the central base portion in the axial direction may be shifted in the second side in the axial direction (in the example shown in FIG. 2A, etc.) from the position of the outer peripheral base portion in the axial direction. above According to this shape of the base plate, the amount of air introduced to the impeller side by driving the cooling fan can be increased. (3) In the structure of (2), the position of at least a part of the peripheral wall portion (upper part in the example shown in FIG. 2A, etc.) in the axial direction may be between the position of the central base portion and the position of the outer peripheral base portion in the axial direction. According to this cooling fan, the amount of components and dust in the air adhering to the components on the circuit board can be more effectively reduced by the peripheral wall portion. (4) In the structure of (2) or (3), the peripheral wall portion extends toward the first side in the axial direction (downward in the example shown in FIG. 2A, etc.) from the central base portion, and the end portion of the peripheral wall portion may be located on the first side in the axial direction from the position of the outer peripheral base portion. According to this cooling fan, the amount of components and dust in the air adhering to the components on the circuit board can be more effectively reduced by the peripheral wall portion. (5) In the structure of (4), the circuit board may be located on the second side in the axial direction (upward in the example shown in FIG. 2A, etc.) from the end portion of the peripheral wall portion (lower end 55a in the example shown in FIG. 2A, etc.). According to this cooling fan, the amount of components and dust in the air adhering to the components on the circuit board can be more effectively reduced by the peripheral wall portion. (6) In the structures of (1) to (5) any one of , the circuit board has a surface facing the central base portion, and a plurality of components may be arranged on the surface of the circuit board. According to this cooling fan, the amount of components and dust in the air adhering to the plurality of components on the circuit board can be more effectively reduced by the peripheral wall portion. (7) In the structures of (1) to (6) any one of , the peripheral wall portion is provided at the outer peripheral edge of the central base portion. While suppressing the passage of air between the central base portion and the peripheral wall portion, a sufficient size of the circuit board can be ensured. (8) In the structures of (1) to (7) any one ofIn the structure, a gap is provided between the outer peripheral edge of the central base portion and the inner peripheral edge of the outer peripheral base portion. An air flow path can be secured between the outer peripheral edge of the central base portion and the inner peripheral edge of the outer peripheral base portion. (9) The electronic device proposed in the present disclosure includes a cooling fan having the structure of (1) to (8), and a housing that houses this cooling fan. According to this electronic device, the amount of components and dust in the air adhering to the components on the circuit board can be reduced by the peripheral wall portion.

[0059] The cooling fan proposed in the present disclosure is not limited to the above-described cooling fan 10, and various modifications may be made. Further, the electronic device proposed in the present disclosure is not limited to the above-described electronic device 90, and various modifications may be made.

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 axis and located on a first side in the axial direction with respect to the central base portion, An impeller located radially outside the electric motor and rotated by driving of the electric motor, A circuit board located between the electric motor and the central base portion for driving the electric motor, A peripheral wall portion surrounding an outer peripheral edge of the circuit board, An air flow introduced toward the impeller is formed between the central base portion and the outer peripheral base portion of the base plate, The position of the central base portion in the axial direction is on a second side opposite to the first side in the axial direction with respect to the position of the outer peripheral base portion in the axial direction. A cooling fan having the above.

2. The position of at least a part of the peripheral wall portion in the axial direction is between the position of the central base portion and the 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 portion of the peripheral wall portion is located on the first side in the axial direction with respect to the position of the outer peripheral base portion. The cooling fan according to Claim 1.

4. The circuit board is located on the second side in the axial direction with respect to the end portion 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 an outer peripheral edge of the central base portion. The cooling fan according to Claim 1.

7. A gap is provided between an outer peripheral edge of the central base portion and an inner peripheral edge of the outer peripheral base portion. The cooling fan according to Claim 1.

8. The cooling fan according to Claim 1, And a housing accommodating the cooling fan. An electronic device having the above.