Backflow prevention device

Abstract

To provide a fan backflow prevention device that can be made smaller and thinner. [Solution] The backflow prevention device (10) of the fan device comprises a main body with an opening, a storage section provided in the center of the opening, a plurality of blades (41) provided in the storage section, and a drive unit (50) provided in the storage section that rotates each of the plurality of blades (41). The rotation of the motor (51) of the drive unit (50) is transmitted to a worm gear (52) ~ first gear (54) ~ internal gear (53), and further linked to a second gear (55) which is connected to the internal gear (53) and rotates in accordance with the rotation of the internal gear (53), thereby rotating the plurality of blades (41) via a blade gear (421) connected to the second gear (55). Depending on the rotation position of the second gear (55), the device switches between a storage state in which the plurality of blades (41) are stored in the storage section and a shielded state in which the plurality of blades (41) shield the opening.

Description

Technical Field

[0001] The present invention relates to a backflow prevention device.

Background Art

[0002] Redundancy is required for electronic devices in which continuous operation such as server devices is performed. For example, a plurality of fan devices are provided for cooling the electronic device, and when one fan device fails, the rotational speed of the remaining fan devices is increased to maintain the cooling characteristics. At this time, by providing a backflow prevention function in the fan device, it is possible to prevent the cooling effect on the electronic device from being reduced due to the backflow air, or the blades from rotating reversely due to the air generated by other non-failed fan devices during the replacement work of the failed fan device, resulting in malfunctions such as sensor malfunction.

[0003] Patent Document 1 discloses a cooling fan system provided with a pneumatic shutter having a plurality of flaps. The plurality of flaps are attached with a slight inclination with respect to the direction of the flow path. During normal operation of the cooling fan system, the plurality of flaps of the pneumatic shutter are positioned substantially parallel to the direction of the flow path, so that the flow path is in an open state. When the cooling system fails and backflow air is generated, the flaps attached with an inclination with respect to the flow path receive the wind pressure of the backflow air. The flap receiving the wind pressure rotates about the support shaft as a fulcrum to close the flow path.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the wind pressure type shutter described in Patent Document 1, multiple flaps move along the flow path. Therefore, it is necessary to ensure a sufficient range of motion for the flaps along the flow path, which leads to a larger device. [Means for solving the problem]

[0006] A backflow prevention device according to one embodiment is a backflow prevention device attached to a fan device, comprising: a main body portion provided with an opening through which airflow in accordance with the rotation of the fan device passes; a storage portion provided in the center of the opening; a plurality of blades provided in the storage portion; and a drive unit provided in the storage portion for rotating each of the plurality of blades on an intersecting plane that intersects with a first direction along the rotation centerline of the fan device. The storage portion is provided with a base portion having a first bottom surface on one end and a second bottom surface on the other end in the first direction. The drive unit comprises a motor; an internal gear; a worm gear and a first gear that transmit the rotation of the motor to the internal gear; and a second gear connected to the internal gear and rotating in accordance with the rotation of the internal gear. The motor, the worm gear, the first gear, and the internal gear are provided on the first bottom surface of the base portion, and the motor, the worm gear, and the first gear are located inside the internal gear. The plurality of blades and the second gear are provided on the second bottom surface of the base portion. The second gear rotates in conjunction with the rotation of the internal gear, thereby rotating the multiple blades, and switches between a stored state in which the multiple blades are stored in the storage section and a shielded state in which the multiple blades shield the opening, depending on the rotation position. [Effects of the Invention]

[0007] According to this disclosure, it becomes possible to miniaturize and thin down the device that prevents backflow of air into the fan device. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a perspective view of the backflow prevention device according to the embodiment. [Figure 2] Figure 2 is a perspective view of the backflow prevention device. [Figure 3] Figure 3 is an exploded perspective view of the backflow prevention device. [Figure 4] Figure 4 is an exploded perspective view of the backflow prevention device. [Figure 5A] Figure 5A is a plan view of the first storage compartment as seen from the rear. [Figure 5B] Figure 5B is a plan view of the first storage compartment as seen from the front. [Figure 6] Figure 6 is a plan view of the external appearance of the blade. [Figure 7A] Figure 7A is a plan view of the first main body in its second state, with the blades and drive unit attached. [Figure 7B] Figure 7B is a plan view of the first main body in its second state, with the blades and drive unit attached. [Figure 8A] Figure 8A is a plan view of the first main body, first storage section, and shielding section in the first state. [Figure 8B] Figure 8B is a plan view of the first main body, first storage section, and shielding section in the first state. [Modes for carrying out the invention]

[0009] Hereinafter, a backflow prevention device according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0010] A backflow prevention device is installed on each of the multiple fan devices that supply cooling air to electronic equipment (the object to be cooled), such as server equipment. The backflow prevention device prevents cooling air that flows in from a working fan device from being discharged to the outside from a malfunctioning fan device by blocking the airflow path when, for example, one of the multiple fan devices is not operating due to a malfunction. For this reason, the backflow prevention device is configured to be able to switch between two operating states: a first state in which the airflow path is not blocked when the fan devices are functioning correctly, and a second state in which the airflow path is blocked when the fan devices malfunction.

[0011] <Overall configuration of the backflow prevention device> Figs. 1 and 2 are external perspective views of the backflow prevention device 10 attached to the fan device 100. Fig. 1 shows the backflow prevention device 10 in the first state (storage state) where the flow path of the cooling air is not shielded, and Fig. 2 shows the backflow prevention device 10 in the second state (shielded state) where the flow path of the cooling air is shielded. The fan device 100 has a fan that rotates about the rotation center line (rotation axis) AX shown in Figs. 1 and 2, and the air flows along the direction of the arrow AR1 (hereinafter referred to as the first direction AR1) in which the rotation axis AX extends due to the rotation of the fan. Figs. 3 and 4 are exploded perspective views of the backflow prevention device 10 in the second state.

[0012] Incidentally, the backflow prevention device 10 may be arranged upstream or downstream of the fan device 100. The backflow prevention device 10 includes a main body portion 20, a storage portion 30, a shielding portion 40, and a driving portion 50.

[0013] <Main body portion 20> The main body portion 20 is a storage portion that houses the shielding portion 40 and the driving portion 50 described later, and is attached to the fan device 100 by fastening members 90 such as bolts and screws. The main body portion 20 has a first main body portion 21 and a second main body portion 22.

[0014] The first main body portion 21 has a rectangular cross-section on a plane (hereinafter referred to as the intersecting plane) that intersects (is orthogonal to) the first direction AR1, and is formed in a rectangular column shape having a thickness along the first direction AR1. Incidentally, the cross-section of the main body portion 20 on the intersecting plane is not limited to a rectangle, and may be formed in a shape corresponding to the cross-sectional shape of the fan device 100 to which the backflow prevention device 10 is attached.

[0015] In the first main body portion 21, an opening 61 is formed on the intersecting plane. The opening 61 penetrates the first main body portion 21 along the first direction AR1. On the intersecting plane, a storage portion 30 is formed in a predetermined range including the central portion of the opening 61. The storage portion 30 is, for example, a circular range centered on the rotation axis AX. The storage portion 30 houses a shielding portion 40 and a driving portion 50, which will be described later. That is, the predetermined range including the central portion of the opening 61 is a range having a size capable of housing the shielding portion 40 and the driving portion 50.

[0016] The second main body portion 22 is a plate-like member formed in a rectangular shape similar to the first main body portion 21 on the intersecting plane. The second main body portion 22 has a shorter length (thickness) along the first direction AR1 than the first main body portion 21. The second main body portion 22 is attached to one surface of the first main body portion 21 in the first direction AR1. Specifically, it is fastened by a fastening member 220 such as a screw, and the latch 210 formed on the edge of the first main body portion 21 and the opening 221 formed on the second main body portion 22 mesh with each other, whereby the second main body portion 22 is attached to the first main body portion 21. Note that the attachment of the first main body portion 21 and the second main body portion 22 is not limited to the above structure.

[0017] Insertion holes are provided at four corners of the second main body portion 22, respectively. The insertion holes penetrate the second main body portion 22 along the first direction AR1. A fastening member 90 for fixing the main body portion 20 to the fan device 100 is inserted into the insertion holes.

[0018] An opening 62 is formed in the second main body portion 22. The opening 62 penetrates the second main body portion 22 along the first direction AR1. The opening 62 has the same shape as the opening 61 formed in the first main body portion 21. The above-described opening 61 and the opening 62 are air duct portions through which the wind (cooling wind) flowing along the first direction AR1 passes in response to the rotational drive of the fan device 100 centered on the rotation axis AX in the first state. Note that in the following description, when the openings 61 and 62 are collectively referred to, they are called the opening 60. Also, a storage portion 30 is formed in a predetermined range including the central portion of the opening 62.

[0019] In the following explanation, the side of the first main body 21 along the first direction AR1 will be referred to as the front, and the side of the second main body 22 will be referred to as the rear. Therefore, Figure 3 is an exploded perspective view of the backflow prevention device 10 as seen from the rear, and Figure 4 is an exploded perspective view of the backflow prevention device 10 as seen from the front.

[0020] <Storage compartment 30> As described above, the storage section 30 is provided in a circular area including the central part of the opening 60. In other words, the area enclosed by the inner wall surface 20a of the first main body 21 that constitutes the main body 20 and the outer wall surface 30a of the storage section 30 is the opening 60. The shielding section 40, which will be described in detail later, is stored in the storage section 30 so as to be deployable into the opening 60. In other words, on the intersecting plane, the storage section 30 has a size that covers a wider area than the shielding section 40 in the first state. The storage section 30 is also provided with a drive unit 50, which will be described in detail later. The storage section 30 is supported by the main body 20 by a support unit 70, which will be described in detail later.

[0021] The storage section 30 includes a first storage section 31, a second storage section 32, and a third storage section 33. As shown in Figures 3 and 4, the first storage section 31 is supported on the first main body section 21 by a plurality of first support sections 71 included in the support section 70. The second storage section 32 is supported on the second main body section 22 by a plurality of second support sections 72 included in the support section 70. The third storage section 33 is attached to the first storage section 31.

[0022] The first storage section 31 is a circular area having a diameter smaller than the diameter of the opening 60 (opening 61). Specifically, the first storage section 31 has a circular base section 310 centered on the axis of rotation AX and parallel or substantially parallel to the intersecting plane, and an outer wall surface 30a connected to the circumference of the base section 310. The outer wall surface 30a protrudes from the base section 310 both forward and backward. In the following description, the bottom surface on the front side (one end) of the base section 310 will be called the first bottom surface 310a, and the bottom surface on the rear side (the other end) will be called the second bottom surface 310b. The first bottom surface 310a and the second bottom surface 310b intersect with the first direction AR1.

[0023] As shown in Figures 3 and 4, a shielding section 40 is positioned on the rear side of the first storage section 31. The first storage section 31 has a size that covers a wider area than the shielding section 40 when it is in the first state (storage state) with the shielding section 40 stored in the intersecting plane. A drive unit 50 is positioned on the front side of the first storage section 31.

[0024] <Storage compartment 31> Figure 5A is a plan view of the first storage section 31 seen from the rear, and Figure 5B is a plan view of the first storage section 31 seen from the front. The base section 310 of the first storage section 31 has a first shaft 311, a second shaft 312, a movable opening 313, and a third shaft 314 formed therein. As shown in Figures 3 and 5A, the first shaft 311 is provided on the second bottom surface 310b on the rear side of the base section 310. The first shaft 311 is a rod-shaped member that protrudes rearward along the first direction AR1 at the center of the base section 310 (i.e., the rotation axis AX). The first shaft 311 rotatably supports the second gear 55, which will be described later.

[0025] The second shaft 312 is provided on the second bottom surface 310b. Multiple second shafts 312 are provided at equal intervals along the circumferential direction of the circular first storage section 31. The second shaft 312 is a rod-shaped member that protrudes rearward from the second bottom surface 310b along the first direction AR1. The second shaft 312 rotatably supports each of the vanes 41 of the shielding section 40, which will be described later. That is, the same number of second shafts 312 are provided as the number of vanes 41. In this embodiment, the case in which nine second shafts 312 are provided according to the number of vanes 41 will be described.

[0026] As shown in Figures 4 and 5B, the third shaft 314 is provided on the first bottom surface 310a on the front side of the base portion 310. The third shaft 314 is a rod-shaped member that protrudes forward along the first direction AR1 at a position radially offset from the center of the base portion 310. The third shaft 314 rotatably supports the first gear 54, which will be described later.

[0027] As shown in Figures 5A and 5B, the movable opening 313 is a through hole formed between the first axis 311 and the second axis 312 in the radial direction of the base portion 310, and penetrates the base portion 310 in the front-rear direction. The movable opening 313 is an internal space surrounded by the first side wall 313a, the second side wall 313b, the third side wall 313c, and the fourth side wall 313d.

[0028] The first side wall 313a and the second side wall 313b are arc-shaped on the intersecting plane. Specifically, the first side wall 313a is centered at the center of the base portion 310 (i.e., the axis of rotation AX) and has a diameter shorter than the radius of the base portion 310. The second side wall 313b is centered at the center of the base portion 310 and has a diameter shorter than the diameter of the first side wall 313a. The central angles of the first side wall 313a and the second side wall 313b are the same or approximately the same.

[0029] The third side wall 313c and the fourth side wall 313d extend along the radial direction of the base portion 310. The third side wall 313c connects with the first side wall 313a and the second side wall 313b at one end. The fourth side wall 313d connects with the first side wall 313a and the second side wall 313b at the other end.

[0030] Since the movable opening 313 is surrounded by the first side wall 313a, second side wall 313b, third side wall 313c, and fourth side wall 313d described above, it is an arc-shaped opening with width along the radial direction of the base portion 310. A projection 551, which will be described later, is inserted into the movable opening 313 so as to be movable inside.

[0031] <Second storage compartment 32> As shown in Figures 3 and 4, the second storage section 32 is a disc-shaped member having a diameter smaller than the diameter of the opening 60 (opening 62) and having a circular shape similar to that of the first storage section 31. Specifically, the second storage section 32 has the same or approximately the same diameter as the base section 310 of the first storage section 31. The shielding section 40 is positioned in front of the second storage section 32.

[0032] <Third storage compartment 33> The third storage section 33 has the same or approximately the same diameter as the base section 310 of the first storage section 31. The third storage section 33 is attached to the first bottom surface 310a of the base section 310 from the front side and covers the storage section 30. The third storage section 33 is fixed to the first bottom surface 310a by fastening members 33a, such as screws.

[0033] <Shielding part 40> The shielding section 40 is composed of a plurality of blades 41 that shield the opening 60. As shown in Figures 3 and 4, the shielding section 40 in this embodiment has nine blades 41. However, the number of blades 41 is not limited to nine. The number of blades 41 is determined according to the size of the fan device 100, that is, the size of the opening 60, so it may be less than nine or nine or more.

[0034] Figure 6 is a plan view of a single blade 41 as seen from the front. The blade 41 is a thin plate-shaped member manufactured from, for example, a metal material. The front and rear sides of the blade 41 are flat surfaces. A blade gear 421 is integrally attached to the flat surface 42 on the front side of the blade 41 in the first direction AR1. A through hole 422 is formed in the center of the blade gear 421. The through hole 422 penetrates the blade gear 421 and the flat surface 42 of the blade 41 in the front-rear direction. The second shaft 312, formed on the second bottom surface 310b of the first storage section 31 as described above, is inserted into the through hole 422 from the front and housed there. Therefore, the blade 41 is rotatably mounted on the second bottom surface 310b of the first storage section 31 with the second shaft 312 as the axis of rotation. In other words, multiple blades 41 are provided in the storage section 30.

[0035] The blade 41 has a first wall surface 43, a second wall surface 44, and a third wall surface 45 as its edges. The first wall surface 43 has a shape that follows the circumference of the opening 60 on the intersecting plane, that is, the inner wall surface 20a of the main body 20. In the second state (shielded state), the first wall surface 43 of the blade 41 and the inner wall surface 20a of the main body 20, which is the circumference of the opening 60, are in contact.

[0036] The second wall surface 44 is connected to the first wall surface 43 at its end 44a and has a shape that follows the circumferential shape of the outer wall surface 30a, which is the edge of the storage section 30, on the intersecting plane. In the first state (storage state), the second wall surface 44 of the wing 41 is located inward in the first direction AR1 relative to the outer wall surface 30a, which is the end of the storage section 30.

[0037] The third wall surface 45 is connected to the end 43a of the first wall surface 43 and the end 44b of the second wall surface 44. The third wall surface 45 is curved to avoid interference with the first shaft 311 provided in the first storage section 31 when in the first state (storage state). The aforementioned vane gear 421 and through hole 422 are provided near the end 44b where the second wall surface 44 and the third wall surface 45 are connected.

[0038] <Drive unit 50> Figure 7A is a plan view of the first main body 21, to which the blades 41 and drive unit 50 are attached, as seen from the front. Figure 7B is a plan view of the first main body 21, to which the blades 41 and drive unit 50 are attached, as seen from the rear. Figures 7A and 7B show the first main body 21 in the second state (shielded state).

[0039] As described above, the drive unit 50 is located in the first housing 31. The drive unit 50 includes a motor 51, a worm gear 52, an internal gear 53, a first gear 54, and a second gear 55. The motor 51, worm gear 52, internal gear 53, and first gear 54 are located on the first bottom surface 310a of the base portion 310 of the first housing 31. As described above, the third housing 33 is attached to the front side of the first housing 31. Therefore, it can also be said that the motor 51, worm gear 52, internal gear 53, and first gear 54 are covered by the third housing 33. The second gear 55 is located on the second bottom surface 310b of the base portion 310 of the first housing 31.

[0040] Various types of motors, such as DC motors and stepper motors, can be used as the motor 51. The motor 51 is positioned on the first bottom surface 310a of the base portion 310 so that its axis of rotation (center of rotation) is aligned with the second direction AR2, which intersects (orthogonal or nearly orthogonal to) the first direction AR1. The motor 51 is electrically connected to the external device, the fan device 100, by electric wires. The motor 51 rotates in response to a drive signal from the external device.

[0041] The worm gear 52 is located at one end of the motor 51. The worm gear 52 extends along the second direction in which the rotation axis of the motor 51 extends and meshes with the first gear 54. The worm gear 52 rotates in accordance with the rotation of the motor 51 and transmits the rotational force of the motor 51 to the first gear 54.

[0042] The first gear 54 is inserted into a third shaft 314 that protrudes forward from the first bottom surface 310a, and is rotatable with respect to the third shaft 314. As described above, the first gear 54 rotates due to the rotational force transmitted from the motor 51 via the worm gear 52. The first gear 54 also meshes with the internal gear 53.

[0043] The internal gear 53 is provided on the first bottom surface 310a. The internal gear 53 is an annular member having an outer diameter equal to or approximately equal to the diameter of the base portion 310. The motor 51, worm gear 52, and first gear 54 described above are arranged within the area enclosed by the inner circumferential wall of the internal gear 53.

[0044] The internal gear 53 has multiple teeth formed along its inner circumferential wall. The teeth of the internal gear 53 mesh with the first gear 54. As a result, the rotational force of the motor 51 is transmitted to the internal gear 53 by the worm gear 52 and the first gear 54, causing the internal gear 53 to rotate around the rotation axis AX.

[0045] The internal gear 53 is provided with a connecting portion 531 that connects to the second gear 55. The connecting portion 531 is a plate-shaped member parallel or substantially parallel to the intersecting plane. The connecting portion 531 is attached to a part of the inner circumferential wall of the internal gear 53 and extends radially inward from the internal gear 53. The connecting portion 531 has an insertion portion 532 formed on the radially inward end face of the internal gear 53. The insertion portion 532 penetrates the connecting portion 531 in the front-rear direction and is an insertion hole into which a part of the second gear 55, which will be described later, is inserted.

[0046] The second gear 55 is attached to the first shaft 311 formed on the second bottom surface 310b of the base portion 310. Specifically, the first shaft 311 is inserted into a through hole formed in the center of the disc-shaped second gear 55 and fixed to the base portion 310 by fastening members 550 such as screws (see Figures 3 and 4). In this way, the second gear 55 is mounted so as to be rotatable around the first shaft 311 as the axis of rotation. That is, the second gear 55 is rotatable about the axis of rotation AX. As shown in Figure 7B, the second gear 55 has teeth formed along its outer circumferential wall and meshes with the vane gears 421 provided on each of the multiple vanes 41 described above.

[0047] Furthermore, the number of teeth on the second gear 55 is related to the number of blades 41. Specifically, the number of teeth on the second gear 55 is an integer multiple of the number of blades 41. That is, in the case where nine blades 41 are provided, as in this embodiment, the number of teeth on the second gear 55 is an integer multiple of nine.

[0048] The second gear 55 and the blade gear 421 of the aforementioned blade 41 are located on the second bottom surface 310b of the base portion 310. Therefore, the diameters of the second gear 55 and the blade gear 421 are smaller than the diameter of the base portion 310. More specifically, the sum of the diameter of the second gear 55 and twice the diameter of the blade gear 421 is smaller than the diameter of the base portion 310.

[0049] As described above, the blade gear 421 is located on the flat surface 42 on the front side of the blade 41. Therefore, when the second gear 55 and the blade gear 421 mesh, the blade 41 is positioned behind the second gear 55.

[0050] The front side of the second gear 55 is provided with a projection 551 that extends forward along the first direction AR1. The projection 551 is positioned in a different location from the rotation axis AX in the intersecting plane. Specifically, the projection 551 is movably inserted into the movable opening 313 when the second gear 55 is attached to the base portion 310. That is, a portion of the projection 551 is movably housed in the movable opening 313.

[0051] The projection 551 penetrates the movable opening 313 and protrudes forward relative to the first bottom surface 310a. The front end of the projection 551 is inserted into the insertion portion 532 of the connecting portion 531 attached to the internal gear 53. As a result, the second gear 55 and the internal gear 53 are connected via the projection 551 and the connecting portion 531. Therefore, the second gear 55 rotates in accordance with the rotation of the internal gear 53, to which the rotational force of the motor 51 is transmitted. In other words, the rotational force of the motor 51 is transmitted to the second gear 55 via the worm gear 52, the first gear 54, and the internal gear 53.

[0052] The rotational force transmitted to the second gear 55 is transmitted to each of the blades 41 via the blade gear 421 which meshes with the second gear 55. In other words, the second gear 55 rotates in conjunction with the rotation of the internal gear 53, thereby rotating the multiple blades 41.

[0053] <Support part 70> The support portion 70 is a member that connects the storage portion 30, which is provided near the center of the opening 60 formed in the main body portion 20, to the main body portion 20, and supports the storage portion 30. The number of support portions 70 is the same as the number of blades 41. That is, in this embodiment, nine support portions 70 are provided.

[0054] Each of the multiple support parts 70 has a curved rod shape that extends along the trajectory of the blade 41 as it rotates on the intersecting plane. The support part 70 has a first support part 71 and a second support part 72 along the first direction AR1. The first support part 71 connects the first main body part 21 and the first storage part 31. The second support part 72 connects the second main body part 22 and the second storage part 32.

[0055] The first support portion 71 and the second support portion 72 overlap with a space S (see Figure 1) along the first direction AR1. The overlap of the first support portion 71 and the second support portion 72 in the first direction AR1 suppresses the reduction in the area of ​​the opening 60 in the first state, thereby suppressing a decrease in the flow rate of the cooling air flowing along the first direction AR1. The vane 41 described above moves on an intersecting plane within this space S, enabling switching between the first state and the second state. In other words, the first support portion 71 and the second support portion 72 are formed such that a distance of at least the thickness of the vane 41 in the first direction AR1 is ensured along the first direction AR1.

[0056] <First state (storage state)> Next, the backflow prevention device 10 in the first state will be described. Figure 8A is a plan view of the first main body 21, the first storage section 31, and the shielding section 40 as seen from the rear in the first state. Figure 8B is a plan view of the first main body 21, the first storage section 31, and the shielding section 40 as seen from the front in the first state.

[0057] As shown in Figure 8A, each of the multiple blades 41 partially overlaps with other blades 41 along the first direction AR1. In each of the multiple blades 41 located on the rear side of the first storage section 31, the second wall surface 44 is further from the center of the opening 61 than the first wall surface 43 and the third wall surface 45. On the intersecting plane, the second wall surface 44 has a shape that follows the outer wall surface 30a of the disc-shaped first storage section 31. Furthermore, since the third wall surface 45 is curved as described above, the blades 41 and the first shaft 311 do not interfere with each other. And, as described above, the storage section 30 has a size that covers a wider area on the intersecting plane than the shielding section 40 in the first state.

[0058] Because the shape of the blades 41 has the above-described relationship with respect to the first storage section 31, as shown in Figures 8A and 8B, none of the multiple blades 41 are exposed to the opening 61. That is, the entire area of ​​all the blades 41 is located on the rear side of the first storage section 31. Therefore, it is possible to house the shielding section 40, consisting of multiple blades 41 that shield the opening 60, within the storage section 30, which is located near the center of the opening 60 and is a narrower area than the opening 60. As a result, in the first state, the blades 41 are prevented from being exposed to the opening 61 and narrowing the area through which the cooling air passes. In other words, it is possible to house the blades 41 without reducing the cooling efficiency of the fan device 100 while ensuring the width of the wind tunnel through which the cooling air passes. In particular, since it is no longer necessary to provide the storage section 30 outside the outer circumference of the opening 60, it is possible to suppress the enlargement of the backflow prevention device 10.

[0059] <Second state (shielded state)> Next, with reference to Figures 7A and 7B, the state of the multiple vanes 41 that are deployed and shield the opening 60 in the second state will be described. As shown in Figure 7B, in each of the multiple vanes 41 located on the rear side of the first storage section 31, the first wall surface 43 is further from the center of the opening 61 than the second wall surface 44 and the third wall surface 45.

[0060] On the intersecting plane, the first wall surface 43 has a shape that conforms to the inner wall surface 20a of the first main body 21. In the second state, the first wall surface 43 is in contact with the inner wall surface 20a. In addition, the edge of each of the multiple blades 41 that follows the second wall surface 44 and the edge of the adjacent blade 41 that follows the third wall surface 45 overlap in the first direction AR1. This suppresses the occurrence of areas in the opening 60 that are not shielded by the shielding portion 40, and thus prevents wind from passing through the opening 60 in the second state.

[0061] <Operation of backflow prevention device 10> As described above, the motor 51 of the drive unit 50 is electrically connected to the fan device 100, which is an external device. The motor 51 is driven in accordance with the drive signal output from the control unit of the fan device 100. The control unit of the fan device 100 is composed of, for example, a CPU and memory. The control unit controls each part of the fan device 100 by reading and executing a control program that is pre-recorded on a recording medium such as flash memory. The control unit determines whether or not a malfunction has occurred in the fan device 100 based on, for example, a pre-recorded fault diagnosis program. When the control unit detects a malfunction in the fan device 100, it outputs a first drive signal to the motor 51 of the reverse current prevention device 10, instructing it to switch from the first state to the second state. Furthermore, when the malfunction in the fan device 100 is removed by repair or the like, and no malfunction is detected in the fan device 100, the control unit outputs a second drive signal to the motor 51 of the reverse current prevention device 10, instructing it to switch from the second state to the first state.

[0062] <Switching operation from state 1 to state 2> When the backflow prevention device 10 is in the first state shown in Figures 8A and 8B, a malfunction is detected in the fan device 100, and a first drive signal is output to the motor 51. The motor 51 then rotates, and the rotational force is transmitted to the first gear 54 via the worm gear 52. The first gear 54 rotates around the third shaft 314 in the rotational direction AR3 shown by the arrow in Figure 8B.

[0063] The internal gear 53, which meshes with the first gear 54, rotates in the direction AR4 indicated by the arrow in Figure 8B, in accordance with the rotation of the first gear 54. As the internal gear 53 rotates in the direction AR4, the connecting portion 531 attached to the internal gear 53 also rotates in the direction AR4.

[0064] As shown in Figure 8B, in the first state, the projection 551 inserted into the insertion portion 532 of the connecting portion 531 is in contact with the fourth side wall 313d of the movable opening 313. The projection 551 rotates in the rotational direction AR4 as the connecting portion 531 rotates in the rotational direction AR4, and moves within the movable opening 313 toward the third side wall 313c.

[0065] As described above, the movable opening 313 is arc-shaped on the intersecting plane. Therefore, the projection 551 moves along the rotational direction AR4 while being guided by the first side wall 313a and the second side wall 313b of the movable opening 313.

[0066] When the projection 551 rotates in the rotational direction AR4, the second gear 55 on which the projection 551 is provided also rotates in the rotational direction AR4 shown in Figure 8A. When the second gear 55 rotates in the rotational direction AR4, all the vane gears 421 that mesh with the second gear 55 rotate in the rotational direction AR5 shown by the arrow in Figure 8A, with the second shaft 312 as the center of rotation. Due to the rotation of the second gear 55, all the vane gears 421 start rotating in the rotational direction AR5 in sync. In other words, the drive unit 50 rotates each of the multiple vanes 41 on the intersecting plane. As a result, all the vanes 41 rotate in sync in the rotational direction AR5 and are deployed from the state in which they were stored in the storage unit 30. That is, at the rotational position after the second gear 55 rotates in the rotational direction AR4, the multiple vanes 41 shield the opening 60 as shown in Figures 7A and 7B, and the backflow prevention device 10 enters the second state.

[0067] Furthermore, the movement of the projection 551 along the rotational direction AR4 within the movable opening 313 is permitted until it comes into contact with the third side wall 313c. In other words, the third side wall 313c restricts the movement of the projection 551 along the rotational direction AR3. This prevents the second gear 55 from rotating excessively, which would cause the amount of rotation of the blades 41 to become too large, resulting in gaps between the blades 41 and a decrease in the shielding accuracy of the opening 60.

[0068] <Switching operation from the second state to the first state> When the motor 51 receives a second drive signal in the second state shown in Figures 7A and 7B, the motor 51 rotates in the opposite direction to when the first drive signal is received. The rotational force from the reverse rotation of the motor 51 is transmitted to the first gear 54 via the worm gear 52. As a result, the first gear 54 rotates around the third shaft 314 in the rotational direction AR6 shown by the arrow in Figure 7A.

[0069] The internal gear 53, which meshes with the first gear 54, and the connecting portion 531 attached to the internal gear 53, rotate in the rotational direction AR7 shown by the arrow in Figure 7A in accordance with the rotation of the first gear 54. As the connecting portion 531 rotates, the projection 551 inserted into the insertion portion 532 moves within the movable opening 313 along the rotational direction AR7. At this time, the projection 551, which was in contact with the third side wall 313c, moves towards the fourth side wall 313d along the rotational direction AR7, guided by the first side wall 313a and the second side wall 313b of the movable opening 313. The movement of the projection 551 within the movable opening 313 along the rotational direction AR7 is possible until it comes into contact with the fourth side wall 313d.

[0070] The movement of this projection 551 causes the second gear 55 to rotate in the rotational direction AR7 shown in Figure 7B. When the second gear 55 rotates in the rotational direction AR7, all the vane gears 421 that mesh with the second gear 55 rotate in the rotational direction AR8 shown by the arrow in Figure 7B, with the second shaft 312 as the center of rotation. The rotation of the second gear 55 causes all the vane gears 421 to start rotating in the rotational direction AR8 in sync. In other words, the drive unit 50 rotates each of the multiple vanes 41 on the intersecting plane. As a result, all the vanes 41 are driven to rotate in sync in the rotational direction AR8, and are retracted into the storage unit 30 from the state where they were deployed in the opening 60, and the opening 60 is opened. In other words, at the rotational position after the second gear 55 rotates in the rotational direction AR7, the multiple vanes 41 are retracted into the storage unit 30, and the backflow prevention device 10 enters the first state.

[0071] As described above, the drive unit 50 rotates the multiple blades 41 on an intersecting plane, enabling switching between a first state (storage state) and a second state (shielded state). In other words, the second gear 55 of the drive unit 50 rotates in conjunction with the rotation of the internal gear 53, rotating the multiple blades 41 and switching the state of the backflow prevention device 10 between the storage state and the shielded state according to the rotation position.

[0072] During the switch between the first and second states, the projection 551 of the second gear 55 moves within the movable opening 313 along the first side wall 313a and the second side wall 313b, in accordance with the rotation of the second gear 55, along the rotational directions AR4 and AR7. As described above, the movable opening 313 is arc-shaped. Therefore, it can be said that the movable opening 313 is arc-shaped, following the trajectory of the movement of the projection 551 along the rotational directions AR4 and AR7.

[0073] Furthermore, the movement of the projection 551 along the rotational direction AR4 is restricted by the third side wall 313c formed at the ends of the first side wall 313a and the second side wall 313b. The movement of the projection 551 along the rotational direction AR7 is restricted by the fourth side wall 313d formed at the ends of the first side wall 313a and the second side wall 313b. In other words, the projection 551 is movable between the third side wall 313c and the fourth side wall 313d. In other words, the lengths of the first side wall 313a and the second side wall 313b of the movable opening 313 correspond to the amount of rotation (rotation angle) of the second gear 55. Since the blade 41 rotates due to the rotation of the second gear 55, it can also be said that the lengths of the first side wall 313a and the second side wall 313b correspond to the amount of rotation (rotation angle) of the blade 41.

[0074] Furthermore, since each of the multiple blades 41 is made of metal, the thickness of the AR1 in the first direction can be reduced while ensuring the strength of the blades 41. Therefore, even in cases such as the first state where multiple blades 41 are arranged in overlapping positions, the overall thickness of the shielding portion 40 in the first direction is suppressed to increase. In addition, since the blades 41 are made of metal, it is difficult for protrusions to form on a flat surface. Therefore, when a blade 41 rotates during the transition between the first and second states, it is suppressed that it may interfere with the rotation of other blades 41 or that its rotation may be hindered by other blades 41.

[0075] According to the above-described embodiment, at least one of the following effects can be obtained.

[0076] (1) The backflow prevention device 10 comprises a storage section 30 provided in the center of an opening 60 provided in the main body 20, a plurality of blades 41 provided in the storage section 30, and a drive unit 50 provided in the storage section that rotates each of the plurality of blades 41 on an intersecting plane. The motor 51, worm gear 52, first gear 54, and internal gear 53 of the drive unit 50 are provided on the first bottom surface 310a of the base section 310, and the motor 51, worm gear 52, and first gear 54 are located inside the internal gear 53. The plurality of blades 41 and second gear 55 are provided on the second bottom surface 310b of the base section 310. The second gear 55 rotates in conjunction with the rotation of the internal gear 53 to rotate the plurality of blades 41, and switches between a storage state in which the plurality of blades 41 are stored in the storage section 30 and a shielding state in which the plurality of blades 41 shield the opening 60 depending on the rotation position.

[0077] Since the motor 51, worm gear 52, and first gear 54 are arranged inside the internal gear 53, the drive unit 50 can be installed in a small space on an intersecting plane such as the first bottom surface 310a of the base portion 310. In other words, the drive unit 50 can be installed within the area where the multiple blades 41 are housed. Therefore, it is possible to ensure sufficient width in the wind tunnel through which the cooling air passes, suppressing a decrease in cooling efficiency by the fan device 100, while suppressing an increase in the size of the backflow prevention device 10.

[0078] Here, we compare this embodiment with a comparative example having a configuration in which the base portion 310 is positioned between the second gear 55 and the blade 41. In the comparative example, the base portion 310 is provided at the above position to prevent noise generation caused by the rotation of the blade 41 in the first direction AR1. In contrast, in this embodiment, the second gear 55 and the blade 41 are provided on the second bottom surface 310b of the base portion 310. Therefore, compared to the comparative example, the length of the member (e.g., the second shaft 312) for fixing the blade 41 to the base portion 310 along the first direction AR1 can be shortened. Consequently, the size (thickness) of the backflow prevention device 10 along the first direction AR1 can be reduced, making it possible to make it thinner.

[0079] (2) Each of the multiple blades 41 is provided with a blade gear 421 that meshes with the second gear 55, and this blade gear is integrated with the blade 41. If the blade 41 and the blade gear 421 are separate, when attaching the blade 41, it is necessary to fix the blade 41 to the blade gear 421 while it is meshed with the second gear 55. In this case, it is necessary to prevent the blade gear 421 from rotating while the blade 41 is fixed to the blade gear 421, which makes assembly work difficult. In contrast, in this embodiment, since the blade 41 and the blade gear 421 are integrated, the attachment of the blade 41 is simplified, and assembly work is improved.

[0080] (3) The second gear 55 has a projection 551 that extends along the first direction AR1. A portion of the projection 551 is movably housed in a movable opening 313 provided in the base portion 310. The projection 551 passes through the movable opening 313 and protrudes toward the first bottom surface 310a, connecting to the internal gear 53. This makes it possible to transmit the rotational force of the motor 51 provided on the first bottom surface 310a to the second gear 55 provided on the second bottom surface 310b with a simple configuration, thereby rotating the blades 41.

[0081] (4) The movable opening 313 is arc-shaped and follows the movement trajectory of the projection 551 which moves in accordance with the rotation of the second gear 55, and has a length corresponding to the rotation angle of the rotating blade 41. As a result, the movable opening 313 can guide the movement of the projection 551, and the third side wall 313c and fourth side wall 313d of the movable opening 313 prevent the projection 551 from moving excessively. As a result, the blade 41 can rotate so that it can switch between a state where it is stored in the storage section 30 and a state where it is deployed in the opening 60.

[0082] (5) The second bottom surface 310b of the base portion 310 is provided with a first shaft 311 that rotatably supports the second gear 55 and a second shaft 312 that rotatably supports the blade 41. The second shaft 312 is inserted into a through hole 422 provided in the blade gear 421. This makes it possible to easily attach the blade 41, which is integrated with the blade gear 421, to the base portion 310 and to mesh the second gear 55 with the blade gear 421. As a result, the attachment of the blade 41 is simplified and the workability during assembly is improved.

[0083] (6) The internal gear 53 has a connecting portion 531 that connects to the projection 551. This allows the rotational force of the motor 51 provided on the first bottom surface 310a to be transmitted to the second gear 55 provided on the second bottom surface 310b via the connecting portion 531 and the projection 551, thereby rotating the blade 41.

[0084] Although various embodiments and modifications have been described above, the present invention is not limited to these. Other embodiments conceivable within the scope of the technical idea of ​​the present invention are also included within the scope of the present invention.

[0085] Furthermore, the fan device 100 may be configured to exhaust air heated by the electronic equipment to the outside, rather than drawing in cooling air to cool the electronic equipment.

[0086] Furthermore, this technology can be configured as follows:

[0087] (1) A backflow prevention device attached to a fan device, comprising: a main body having an opening through which airflow in accordance with the rotation of the fan device passes; a storage section provided in the center of the opening; a plurality of blades provided in the storage section; and a drive unit provided in the storage section for rotating each of the plurality of blades on an intersecting plane that intersects with a first direction along the rotation centerline of the fan device, wherein the storage section is provided with a base having a first bottom surface on one end and a second bottom surface on the other end in the first direction, and the drive unit comprises a motor, an internal gear, a worm gear and a first gear that transmit the rotation of the motor to the internal gear A backflow prevention device comprising: a motor, a worm gear, a first gear, and an internal gear, the motor, the worm gear, the first gear, and the internal gear are provided on the first bottom surface of the base portion, the motor, the worm gear, and the first gear are located inside the internal gear, the plurality of blades and the second gear are provided on the second bottom surface of the base portion, the second gear rotates in conjunction with the rotation of the internal gear to rotate the plurality of blades, and switches between a stored state in which the plurality of blades are stored in the storage portion and a shielded state in which the plurality of blades shield the opening, depending on the rotation position.

[0088] (2) The backflow prevention device according to (1), wherein each of the plurality of blades is provided integrally with the blade, a blade gear that meshes with the second gear.

[0089] (3) The backflow prevention device according to (1) or (2), wherein the second gear has a projection extending along the first direction, the base portion is provided with a movable opening for movably housing a part of the projection, the projection passes through the movable opening and protrudes toward the first bottom surface and connects with the internal gear.

[0090] (4) The backflow prevention device according to (3), wherein the movable opening is arc-shaped along the trajectory of the projection that moves in accordance with the rotation of the second gear and has a length corresponding to the rotation angle of the rotating blade.

[0091] (5) The backflow prevention device according to any one of (2) to (4), wherein the second bottom surface of the base portion is provided with a first shaft that rotatably supports the second gear and a second shaft that rotatably supports the blade, and the blade gear is provided with a through hole for housing the second shaft.

[0092] (6) The backflow prevention device according to any one of (3) to (5), wherein the motor rotates with a second direction intersecting the first direction as its center of rotation, the worm gear extends along the second direction and rotates in conjunction with the rotation of the motor, the first gear meshes with the worm gear and the internal gear and transmits rotational force to the internal gear by rotating in conjunction with the rotation of the worm gear, and the internal gear has a connecting portion that connects to the projection and rotates the second gear by rotating in conjunction with the rotation of the first gear. [Explanation of symbols]

[0093] 10 Backflow prevention device, 20 Main body, 21 First main body, 22 Second main body, 30 Storage section, 31 First storage section, 32 Second storage section, 33 Third storage section, 40 Shielding section, 41 Blades, 50 Drive section, 51 Motor, 52 Worm gear, 53 Internal gear, 54 First gear, 55 Second gear, 60, 61, 62 Opening, 70 Support section, 71 First support section, 72 Second support section, 100 Fan device, 310 Base section, 310a First bottom surface, 310b Second bottom surface, 311 First shaft, 312 Second shaft, 313 Moving opening, 314 Third shaft, 421 Blade gear, 531 Connecting section, 551 Protrusion

Claims

1. A backflow prevention device attached to a fan device, The main body is provided with an opening through which the airflow that flows in accordance with the rotation of the fan device passes, A storage compartment is provided in the center of the aforementioned opening, Multiple blades provided in the aforementioned storage section, The storage unit is provided with a drive unit that rotates each of the multiple blades on an intersecting plane that intersects with a first direction along the rotation centerline of the fan device, The storage section is provided with a base portion having a first bottom surface on one end and a second bottom surface on the other end in the first direction. The drive unit comprises a motor, an internal gear, a worm gear and a first gear that transmit the rotation of the motor to the internal gear, and a second gear connected to the internal gear and rotating in accordance with the rotation of the internal gear. The motor, the worm gear, the first gear, and the internal gear are provided on the first bottom surface of the base portion. The motor, the worm gear, and the first gear are located inside the internal gear. The multiple blades and the second gear are provided on the second bottom surface of the base portion. The second gear rotates in conjunction with the rotation of the internal gear, thereby rotating a plurality of the vanes, and switches between a stored state in which the plurality of vanes are stored in the storage section and a shielded state in which the plurality of vanes shield the opening, depending on the rotation position, in this backflow prevention device.

2. In the backflow prevention device according to claim 1, A backflow prevention device wherein each of the multiple blades is provided with a blade gear that meshes with the second gear, and the blade is integrally provided with the blade.

3. In the backflow prevention device according to claim 2, The second gear has a projection extending along the first direction, The base portion is provided with a movable opening that movably accommodates a part of the projection, The aforementioned projection extends through the movable opening and protrudes from the first bottom surface, connecting to the internal gear, and is a backflow prevention device.

4. In the backflow prevention device according to claim 3, The moving opening is arc-shaped, following the movement trajectory of the projection that moves in accordance with the rotation of the second gear, and has a length corresponding to the rotation angle of the rotating blade, in a backflow prevention device.

5. In the backflow prevention device according to claim 4, The second bottom surface of the base portion is provided with a first shaft that rotatably supports the second gear and a second shaft that rotatably supports the blade. The vane gear is provided with a through hole for housing the second shaft, thus preventing backflow.

6. In the backflow prevention device according to claim 3, The motor rotates with a second direction intersecting the first direction as its center of rotation. The worm gear extends along the second direction and rotates in conjunction with the rotation of the motor. The first gear meshes with the worm gear and the internal gear, and rotates in conjunction with the rotation of the worm gear, thereby transmitting rotational force to the internal gear. The internal gear has a connecting portion that connects to the projection, and rotates in conjunction with the rotation of the first gear, thereby causing the second gear to rotate, thus preventing backflow.

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