FAN

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Application No. 2024-228172 filed with the Japan Patent Office on Dec. 25, 2024, the entire content of which is hereby incorporated by reference.

BACKGROUND

1. Technical Field

One aspect of the present disclosure relates to a fan.

2. Related Art

A tubular portion that extends in an axial direction and accommodates an impeller unit, a base plate portion located in the tubular portion, and a stator blade that extends in a radial direction between the tubular portion and the base plate portion are integrally included in a frame member of a fan known by, for example, Japanese U.S. Pat. No. 3,904,595. The base plate portion of the frame member supports a circuit board of a motor. Moreover, the base plate portion encourages dissipation of heat from the circuit board.

SUMMARY

A fan including: a motor configured to rotate an impeller unit; and a frame member including: a cylindrical housing; a base plate portion provided in the housing; and a stator blade extending between the base plate portion and the housing, in which the base plate portion is provided with a circuit board of the motor, a front surface on the impeller unit side of the base plate portion is provided with a protruding portion projecting toward the circuit board, and an inner peripheral portion of a back surface of the base plate portion is recessed into the impeller unit side relative to an outer peripheral edge portion of the back surface.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a vertical cross-sectional view of a fan according to an embodiment of the present disclosure;

FIG. 2 is a perspective view of a frame member as viewed from an upstream side; and

FIG. 3 is a perspective view of the frame member as viewed from a downstream side.

DETAILED DESCRIPTION

In the following detailed description, for purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

An increase in the dimension of the stator blade in the axial direction leads to an increase in the distance in the axial direction between the base plate portion and the circuit board of the motor. Hence, it is conceivable to bring a supporting surface, which supports the circuit board, of the base plate portion close to the circuit board. However, an outer peripheral edge of the base plate portion also has a function of supporting a radially inner portion of the stator blade. Hence, if it is attempted to bring the supporting surface of the base plate portion close to the circuit board, the base plate portion results in becoming a member that is thick in the axial direction. Therefore, this measure is not realistic.

On the other hand, it is conceivable to form a protruding portion extending from the base plate portion toward the circuit board to support the circuit board and facilitate depriving heat of the circuit board. However, if the distance in the axial direction between the base plate portion and the circuit board of the motor is long, the protruding portion becomes too long. Hence, when the frame member is cast, castability of the protruding portion is deteriorated. As a result, it is difficult to form the protruding portion into an intended shape.

Hence, one object of the present disclosure is to provide a fan including a frame member that is easy to be produced into a desired shape.

A fan according to an aspect of the present disclosure includes: a motor configured to rotate an impeller unit; and a frame member including: a cylindrical housing; a base plate portion provided in the housing; and a stator blade extending between the base plate portion and the housing, in which the base plate portion is provided with a circuit board of the motor, a front surface on the impeller unit side of the base plate portion is provided with a protruding portion projecting toward the circuit board, and an inner peripheral portion of a back surface of the base plate portion is recessed into the impeller unit side relative to an outer peripheral edge portion of the back surface.

According to one aspect of the present disclosure, a fan including a frame member that is easy to be produced into a desired shape is provided.

An embodiment of the present disclosure is described hereinafter with reference to the drawings. Note that descriptions of configurations having the same reference numerals as configurations already described are omitted in the detailed description for convenience of description.

FIG. 1 is a vertical cross-sectional view of a fan 1 according to the embodiment of the present disclosure. FIG. 1 illustrates the left half of the fan 1. As illustrated in FIG. 1, the fan 1 includes an impeller unit 10 that rotates about a rotation axis Ax, a frame member 20, a stator core 80, and a motor 30. In FIG. 1, an upper side/upward in the page is referred to as an upstream side/upstream, and a lower side/downward in the page is referred to as a downstream side/downward. The fan 1 produces a current of air flowing from upstream to downstream.

The impeller unit 10 includes a rotational shaft portion 11, an impeller cup 12, and a rotor blade 13. The rotational shaft portion 11 is an axial portion extending in a direction of the rotation axis Ax. The rotational shaft portion 11 is rotatably supported by a bearing portion 50 fixed to the frame member 20. The impeller cup 12 is a cup-shaped member that is open to the downstream side. The rotational shaft portion 11 extends from the center of the impeller cup 12 toward the downstream side. A cylindrical permanent magnet 31 is attached to an inner peripheral surface of the impeller cup 12. The rotor blade 13 is provided to an outer peripheral surface of the impeller cup 12.

The motor 30 includes the permanent magnet 31 attached to the impeller cup 12, a winding 32, and a circuit board 33. The circuit board 33 supplies power to the motor 30, and controls the motor 30. The motor 30 causes a magnetic force to act between the winding 32 and the permanent magnet 31 to rotate the impeller unit 10 about the rotation axis Ax.

The stator core 80 includes a tooth portion. The winding 32, which is provided at a position facing the permanent magnet 31, of the motor 30 is wound around the tooth portion. The stator core 80, together with the winding 32, forms a stator coil. The stator core 80 is provided with a through-hole extending in the direction of the rotation axis Ax. A shaft support portion 21, which is described below, of the frame member 20 penetrates and supports the stator core 80.

FIG. 2 is a perspective view of the frame member 20 as viewed from the upstream side. As illustrated in FIGS. 1 and 2, the shaft support portion 21, a housing 23, a stator blade 24, and a base plate portion 40 are integrally included in the frame member 20. The frame member 20 is a casting.

The shaft support portion 21 is provided at a radially center portion of the frame member 20, and extends in the direction of the rotation axis Ax. The shaft support portion 21, together with an inner tubular portion 41, which is described below, of the base plate portion 40, supports the rotational shaft portion 11 of the impeller unit 10 in a manner that allows rotation of the rotational shaft portion 11 about the rotation axis Ax. Moreover, the shaft support portion 21 also supports the stator core 80. As illustrated in FIG. 1, the bearing portion 50 is provided inside the shaft support portion 21 and the inner tubular portion 41. An outer ring 51 of the bearing portion 50 is fixed to an inner peripheral surface of the shaft support portion 21 and an inner peripheral surface of the inner tubular portion 41. An inner ring 52 of the bearing portion 50 is fixed to the rotational shaft portion 11 of the impeller unit 10.

The housing 23 is a cylindrical portion extending along the direction of the rotation axis Ax. The impeller cup 12 is accommodated in the housing 23 in such a manner as to be rotatable. The housing 23 has a larger diameter than the shaft support portion 21. A flow path P is formed between the housing 23 and the impeller cup 12. Air flows along the direction of the rotation axis Ax in the flow path P.

The base plate portion 40 is provided to a downstream end portion of the fan 1. The circuit board 33 of the motor 30 is attached to the base plate portion 40. The base plate portion 40 includes the inner tubular portion 41, an outer tubular portion 42, and a ring disk portion 43 that connects downstream end portions of the inner tubular portion 41 and the outer tubular portion 42.

The stator blade 24 has a function of rectifying a current of air produced by the rotation of the impeller cup 12 and passing the air downward. The stator blade 24 is provided in such a manner as to extend in a radial direction between the outer tubular portion 42 of the base plate portion 40 and an inner peripheral surface of the housing 23.

The outer tubular portion 42 is provided at an outer peripheral edge of the base plate portion 40 in such a manner as to bend upstream from an outer peripheral edge of the ring disk portion 43. A space is provided between the outer tubular portion 42 and the inner tubular portion 41. A downstream end portion of the space is blocked by the ring disk portion 43.

A radially inner end portion of the stator blade 24 is connected to an outer peripheral surface of the outer tubular portion 42. In other words, the outer tubular portion 42 supports the stator blade 24. It is preferable that a connection portion (an outer peripheral edge portion 46 of the base plate portion 40) between the outer tubular portion 42 and the ring disk portion 43 be formed to be thicker than the other portion as illustrated in FIG. 1. Consequently, support stiffness of the stator blade 24 can be increased.

As illustrated in FIG. 2, a surface on an upstream side (an impeller unit 10 side) of the ring disk portion 43 of the base plate portion 40 is provided with a plurality of protruding portions 44 projecting toward the circuit board 33. Note that in the following description, the surface on the upstream side of the base plate portion 40 is referred to as a front surface, and a surface on a downstream side of the base plate portion 40 is referred to as a back surface. The protruding portions 44 are rectangular portions as viewed in the direction of the rotation axis Ax. As illustrated in FIG. 1, a thermal pad 60 is provided on surfaces on upstream sides of the protruding portions 44. The protruding portions 44 support the circuit board 33 via the thermal pad 60.

FIG. 3 is a perspective view of the frame member 20 as viewed from the downstream side. As illustrated in FIGS. 1 and 3, an inner peripheral portion 45 of the back surface of the base plate portion 40 is recessed into the upstream side (the impeller side) relative to the outer peripheral edge portion 46 of the back surface of the base plate portion 40. In other words, assuming that the outer peripheral edge portion 46 of the base plate portion 40 is defined as a downstream end portion in the direction of the rotation axis Ax, the inner peripheral portion 45 of the back surface of the base plate portion 40 is located at a position recessed by a length L (refer to FIG. 1) from the downstream end portion. In other words, as compared to a case where the protruding portions 44 are extended upstream while the inner peripheral portion 45 of the base plate portion 40 stays at the downstream end portion, the protruding portions 44 are reduced in length by the length L in the fan 1 of the embodiment.

An increase in the dimension of the stator blade 24 in an axial direction leads to an increase in the distance in the direction of the rotation axis Ax between the base plate portion 40 and the circuit board 33 of the motor 30.

Hence, it is conceivable to bring a supporting surface (the front surface), which supports the circuit board, of the base plate portion 40 close to the circuit board 33. However, the outer peripheral edge of the base plate portion 40 also has a function of supporting a radially inner portion of the stator blade 24. Therefore, it is preferable to maintain support stiffness of the base plate portion 40 by leaving the position of the back surface of the base plate portion 40 in the direction of the rotation axis Ax unchanged. Hence, if it is attempted to bring the supporting surface of the base plate portion 40 close to the circuit board 33, the base plate portion 40 results in becoming a member that is thick in the axial direction. Therefore, this measure is not realistic.

On the other hand, it is conceivable to form the protruding portions 44 extending from the base plate portion 40 toward the circuit board 33 and cause the protruding portions 44 to support the circuit board 33 and facilitate depriving heat of the circuit board 33. However, if the distance in the direction of the rotation axis Ax between the base plate portion 40 and the circuit board 33 of the motor 30, that is, the dimension of the stator blade 24 in the axial direction, is long, the protruding portions 44 become too long. Hence, when the frame member 20 is cast, castability of the protruding portions 44 is deteriorated. As a result, it is difficult to form the protruding portions 44 into an intended shape.

Hence, in the fan 1 of the embodiment, the inner peripheral portion 45 is recessed into the upstream side (the impeller unit 10 side) relative to the outer peripheral edge portion 46 on the surface on the downstream side of the base plate portion 40 (the back surface of the base plate portion 40) as illustrated in FIGS. 1 and 2. Consequently, as compared to the case where the protruding portions 44 are extended upstream while the inner peripheral portion 45 of the base plate portion 40 stays at the downstream end portion, the protruding portions 44 are reduced in length by the length L in the fan 1 of the embodiment. Therefore, the amount of molten metal required to be poured into the protruding portions 44 upon casting of the frame member 20 is reduced in the fan 1. Hence, it is easy to mold the frame member 20 including the protruding portions 44 by casting. Moreover, in the embodiment, the thermal pad 60 is provided between the protruding portions 44 and the circuit board 33. Hence, the length of the protruding portions 44 in the direction of the rotation axis Ax is further reduced.

Note that the inner peripheral portion 45 of the base plate portion 40 is provided with the inner tubular portion 41 that, together with the shaft support portion 21, supports the rotational shaft portion 11 of the impeller unit 10. The inner tubular portion 41 is provided downstream of the shaft support portion 21 in the direction of the rotation axis Ax. Moreover, an outer diameter of the inner tubular portion 41 is greater than an outer diameter of the shaft support portion 21. Hence, a step surface 47 is provided between the inner tubular portion 41 and the shaft support portion 21 (a boundary portion). An approximately ring disk-shaped circuit board 33 is brought into contact with the step surface 47. Therefore, the position of the circuit board 33 in the direction of the rotation axis Ax is restricted.

The circuit board 33 includes a terminal portion 35 to which the wiring (lead) 32 extending from the stator coil is fixed. The terminal portion 35 is provided at a position corresponding to the protruding portion 44. A high current is supplied from the circuit board 33 to the winding 32 via the terminal portion 35. Therefore, the terminal portion 35 is more likely to generate heat than the other portion of the circuit board 33. The terminal portion 35 is mounted on a surface on an upstream side of the circuit board 33. A mounting leg portion of the terminal portion 35 is provided in such a manner as to penetrate the circuit board 33. The mounting leg portion of the terminal portion 35 juts out from a surface on a downstream side of the circuit board 33. The jutting portion is soldered to the thermal pad 60. It is preferable that the protruding portion 44 extending from the base plate portion 40 be provided at a position that supports a surface on a downstream side of the mounting leg portion of the terminal portion 35 via the thermal pad 60. Consequently, the circuit board 33 can be cooled effectively.

Moreover, as illustrated in FIG. 1, a gap G is provided between a side surface of the circuit board 33 and an inner peripheral surface of the base plate portion 40 in the fan 1 of the embodiment. Specifically, the gap G is provided between a side peripheral surface of the circuit board 33 and an inner peripheral surface of the outer tubular portion 42 of the base plate portion 40.

During operation of the fan 1, air flows along the flow path P between the housing 23 and the impeller cup 12. Hence, air in an exhaust heat space S between the circuit board 33 and the ring disk portion 43 of the base plate portion 40 is sucked out through the gap G between the side peripheral surface of the circuit board 33 and the inner peripheral surface of the outer tubular portion 42 of the base plate portion 40. The protruding portions 44 to which the heat of the circuit board 33 is transferred are located in the exhaust heat space S. Hence, high-temperature air builds up in the exhaust heat space S. In terms of this, in the embodiment, the high-temperature air in the exhaust heat space S can be sucked out into the flow path P between the impeller cup 12 and the housing 23 through the gap G between the side peripheral surface of the circuit board 33 and the inner peripheral surface of the outer tubular portion 42 of the base plate portion 40. Therefore, the efficiency of cooling of the circuit board 33 by the protruding portion 44 is increased.

Moreover, in the embodiment, the inner peripheral portion 45 of the ring disk portion 43 of the base plate portion 40 is placed in such a manner as to be displaced upstream in the direction of the rotation axis Ax relative to the outer peripheral edge portion 46. Hence, the length of the exhaust heat space S in the direction of the rotation axis Ax is reduced. Hence, the volume of the exhaust heat space S is reduced. Therefore, the exhaust heat space S can be ventilated efficiently.

Moreover, in the embodiment, a recessed portion 48 recessed in a direction away from the impeller unit 10 is provided on the surface on the upstream side of the base plate portion 40 as illustrated in FIG. 2. In some cases, components having a larger dimension in the direction of the rotation axis Ax than other electronic components, such as a capacitor, are mounted on the circuit board 33. Hence, the recessed portion 48 may be provided on the front surface of the base plate portion 40 in such a manner as to avoid contact of these components having a larger dimension in the direction of the rotation axis Ax with the front surface of the base plate portion 40. Consequently, it is possible to make the exhaust heat space S small while enabling the accommodation of larger components.

Moreover, in the embodiment, a nameplate 70 is affixed to the back surface of the base plate portion 40 as illustrated in FIG. 1. The inner peripheral portion 45 recessed into the upstream side relative to the downstream end portion of the back surface of the base plate portion 40 is formed in such a manner as to have almost the same size (substantially the same size) as the nameplate 70. Consequently, it is easy to determine the position of the nameplate 70 when the nameplate 70 is affixed to the base plate portion 40.

Note that in the embodiment, the outer peripheral edge portion 46 of the back surface of the base plate portion 40 is raised. Hence, it is hard for other members and a user's finger to touch the nameplate 70 affixed to the inner peripheral portion 45 of the base plate portion 40. Therefore, it is easy to protect the nameplate 70.

Up to this point the embodiments according to the present disclosure have been described. However, it is needless to say that the technical scope of the present disclosure should not be construed in a limited manner by the detailed description. The above-described embodiments are mere exemplifications. Those skilled in the art understand that the above-described embodiments can be modified in various manners within the scope of the disclosure of the claims. The technical scope of the present disclosure should be determined on the basis of the scope of the disclosure of the claims and the scope of equivalents thereof.

The foregoing detailed description has been presented for the purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. It is not intended to be exhaustive or to limit the subject matter described herein to the precise form disclosed. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims appended hereto.