fan

Abstract

To provide a fan having frame members that are easy to manufacture into a desired shape. [Solution] The fan 1 has a motor 30 that rotates the impeller unit 10, and a frame member 20 having a housing 23, a bottom plate portion 40, and stator blades 24. The bottom plate portion 40 is provided with a circuit board 33 for the motor 30. A protrusion 44 is provided on the surface of the bottom plate portion 40 on the impeller unit 10 side, projecting toward the circuit board 33. On the back surface of the bottom plate portion 40, the inner circumference portion 45 is recessed toward the impeller unit 10 than the outer circumference portion 46.

Description

Technical Field

[0001] The present invention relates to a fan.

Background Art

[0002] A fan having a frame member integrally provided with an axially extending cylindrical portion that houses an impeller unit, a bottom plate portion located inside the cylindrical portion, and a stator blade extending radially between the cylindrical portion and the bottom plate portion is known from Patent Document 1 and the like. The circuit board of the motor is supported by the bottom plate portion of the frame member. Further, heat dissipation of the circuit board is achieved by the bottom plate portion.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, when the axial dimension of the stator blade increases, the axial distance between the bottom plate portion and the circuit board of the motor increases. Therefore, it is conceivable to bring the support surface of the bottom plate portion closer to the circuit board. However, since the outer peripheral edge of the bottom plate portion also functions to support the radially inner portion of the stator blade, if the support surface of the bottom plate portion is brought closer to the circuit board, the bottom plate portion becomes a thick member in the axial direction, which is not practical. On the other hand, it is conceivable to extend a convex portion from the bottom plate portion toward the circuit board, support the circuit board by the convex portion, and also make it easier to take heat from the circuit board. However, when the axial distance is large, the convex portion becomes too long, and the flowability of the molten metal around the convex portion deteriorates when casting the frame member, making it difficult to form the desired shape. Therefore, an object of the present disclosure is to provide a fan having a frame member that is easy to manufacture into a desired shape.

Means for Solving the Problems

[0005] A fan according to one aspect of the present invention is A motor that rotates the impeller, The frame member comprises a cylindrical housing, a cylindrical portion, a stator blade extending between the cylindrical portion and the housing, and a bottom plate portion provided inside the cylindrical portion. The motor's circuit board is provided on the bottom plate portion. A protrusion is provided on the surface of the bottom plate portion on the impeller side, which protrudes toward the substrate. The underside of the bottom plate portion is recessed towards the impeller at its inner circumference compared to its outer edge. [Effects of the Invention]

[0006] According to this disclosure, a fan is provided having a frame member that is easy to manufacture into a desired shape. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a longitudinal cross-sectional view of a fan according to an embodiment of this disclosure. [Figure 2] Figure 2 is a perspective view of the frame members from the upstream side. [Figure 3] Figure 3 is a perspective view of the frame member from the downstream side. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to the drawings. For the sake of clarity, configurations having the same reference numerals as those already described will be omitted from the description of the embodiments.

[0009] Figure 1 is a longitudinal cross-sectional view of a fan 1 according to an embodiment of the present disclosure. Figure 1 shows the left half of the fan 1. As shown in Figure 1, the fan 1 has an impeller unit 10 that rotates around a rotation axis Ax, a frame member 20, a stator core 80, and a motor 30. In Figure 1, the upper part of the paper is called the upstream, and the lower part of the paper is called the downstream. The fan 1 generates an airflow from upstream to downstream.

[0010] The impeller unit 10 includes a rotating shaft portion 11, an impeller cup 12, and rotor blades 13. The rotating shaft portion 11 is an axial part extending in the direction of the rotation axis Ax. The rotating 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 opens toward the downstream. The rotating shaft portion 11 extends from the center of the impeller cup 12 toward the downstream. A cylindrical permanent magnet 31 is attached to the inner circumferential surface of the impeller cup 12. The rotor blades 13 are provided on the outer circumferential surface of the impeller cup 12.

[0011] The motor 30 has a 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 acts a magnetic force between the winding 32 and the permanent magnet 31, causing the impeller unit 10 to rotate around the rotation axis Ax.

[0012] The stator core 80 has teeth on which the windings 32 of the motor 30 are wound, positioned opposite the permanent magnet 31. The stator core 80, together with the windings 32, constitutes the stator coil. The stator core 80 is provided with through holes extending in the direction of the rotation axis Ax. The stator core 80 is supported by passing through the shaft support portion 21 of the frame member 20, which will be described later.

[0013] Figure 2 is a perspective view of the frame member 20 from the upstream side. As shown in Figures 1 and 2, the frame member 20 integrally comprises a shaft support portion 21, a housing 23, a stator blade 24, and a bottom plate portion 40. The frame member 20 is a casting.

[0014] The shaft support portion 21 is provided at the radially central portion of the frame member 20 and is a portion extending in the direction of the rotation axis Ax. The shaft support portion 21, together with the inner cylinder portion 41 of the bottom plate portion 40 described later, supports the rotating shaft portion 11 of the impeller unit 10 so as to be rotatable about the rotation axis Ax. Also, the shaft support portion 21 supports the stator core 80. As shown in FIG. 1, a bearing portion 50 is provided inside the shaft support portion 21 and the inner cylinder portion 41. The outer ring 51 of the bearing portion 50 is fixed to the inner peripheral surfaces of the shaft support portion 21 and the inner cylinder portion 41, and the inner ring 52 of the bearing portion 50 is fixed to the rotating shaft portion 11 of the impeller unit 10.

[0015] The housing 23 is a cylindrical portion extending along the direction of the rotation axis Ax. The impeller cup 12 is rotatably accommodated inside the housing 23. The housing 23 has a larger diameter than the shaft support portion 21. A flow path P through which air flows along the direction of the rotation axis Ax is formed between the housing 23 and the impeller cup 12.

[0016] The bottom plate portion 40 is provided at the downstream end of the fan 1. A circuit board 33 of the motor 30 is attached to the bottom plate portion 40. The bottom plate portion 40 has an inner cylinder portion 41, an outer cylinder portion 42, and a ring disk portion 43 that connects the downstream ends of the inner cylinder portion 41 and the outer cylinder portion 42.

[0017] The stator blade 24 functions to rectify the air flow generated by the rotation of the impeller cup 12 and flow it downstream. The stator blade 24 is provided so as to extend radially between the outer cylinder portion 42 of the bottom plate portion 40 and the inner peripheral surface of the housing 23.

[0018] An outer cylinder portion 42 bent upstream from the outer peripheral edge of the ring disk portion 43 is provided at the outer peripheral edge of the bottom plate portion 40. A space is provided between the outer cylinder portion 42 and the inner cylinder portion 41. The downstream end of this space is blocked by the ring disk portion 43.

[0019] The radially inner end of the stator blade 24 is connected to the outer peripheral surface of the outer cylinder portion 42. That is, the outer cylinder portion 42 supports the stator blade 24. As shown in FIG. 1, it is preferable that the connection portion (the outer peripheral edge portion 46 of the bottom plate portion) between the outer cylinder portion 42 and the ring disc portion 43 is formed to be thicker than other portions. Thereby, the support rigidity of the stator blade 24 can be enhanced.

[0020] As shown in FIG. 2, a plurality of convex portions 44 protruding toward the circuit board 33 are provided on the surface of the ring disc portion 43 on the upstream side (the impeller unit 10 side) of the bottom plate portion 40. In the following description, the surface on the upstream side of the bottom plate portion 40 is referred to as the front surface, and the surface on the downstream side of the bottom plate portion 40 is referred to as the back surface. This convex portion 44 is a substantially rectangular portion when viewed from the direction of the rotation axis Ax. As shown in FIG. 1, a heat transfer pad 60 is provided on the upstream surface of this convex portion 44, and the convex portion 44 supports the circuit board 33 via the heat transfer pad 60.

[0021] FIG. 3 is a perspective view of the frame member 20 as viewed from the downstream side. As shown in FIGS. 1 and 3, the back surface of the bottom plate portion 40 has an inner peripheral portion 45 recessed more upstream (the impeller side) than the outer peripheral edge portion 46. That is, when the outer peripheral edge portion 46 of the bottom plate portion 40 is defined as the downstream end in the direction of the rotation axis Ax, the inner peripheral portion 45 of the back surface of the bottom plate portion 40 is located at a position recessed by a length L (see FIG. 1) from the downstream end. That is, compared with the case where the convex portion 44 is extended upstream while the inner peripheral portion 45 of the bottom plate portion 40 is positioned at the downstream end, in the fan 1 of the present embodiment, the length of the convex portion 44 is shortened by the length L.

[0022] By the way, when the axial dimension of the stator blade 24 becomes large, the distance in the direction of the rotation axis Ax between the bottom plate portion 40 and the circuit board 33 of the motor 30 becomes large. Therefore, it is conceivable to bring the support surface of the bottom plate 40 closer to the circuit board 33. However, since the outer edge of the bottom plate 40 also functions to support the radially inner portion of the stator blade 24, the back surface of the bottom plate 40 needs to maintain its position in the direction of the rotation axis Ax in order to maintain support rigidity. For this reason, if we try to bring the support surface of the bottom plate 40 closer to the circuit board 33, the bottom plate 40 will become a thicker member in the axial direction, which is not practical. On the other hand, it is conceivable to extend a protrusion 44 from the bottom plate portion 40 toward the circuit board 33, with the protrusion 44 supporting the circuit board 33 and also facilitating heat dissipation from the circuit board 33. However, if the axial dimension is large, the protrusion 44 becomes too long, which worsens the flow of molten metal through the protrusion 44 when casting the frame member 20, making it difficult to form the desired shape.

[0023] Therefore, in the fan 1 of this embodiment, as shown in Figures 1 and 2, the downstream surface of the bottom plate portion 40 (the back surface of the bottom plate portion 40) has an inner circumference portion 45 that is recessed upstream (towards the impeller unit 10) of the outer circumference portion 46. As a result, compared to the case where the convex portion 44 is extended upstream while the inner circumference portion 45 of the bottom plate portion 40 is positioned at the downstream end, the length of the convex portion 44 is shorter by a length L in the fan 1 of this embodiment. Since the amount of molten metal to be poured into the convex portion 44 is reduced in this way, the frame member 20 including the convex portion 44 is easier to mold by casting. Furthermore, in this embodiment, since a heat transfer pad 60 is provided between the protrusion 44 and the circuit board 33, the length of the protrusion 44 in the direction of the rotation axis Ax is further shortened.

[0024] Furthermore, the inner circumference portion 45 of the bottom plate portion 40 is provided with an inner cylinder portion 41 that supports the rotating shaft portion 11 of the impeller unit 10, together with the shaft support portion 21. The inner cylinder portion 41 is located downstream of the shaft support portion 21 in the direction of the rotation axis Ax. The inner cylinder portion 41 has a smaller diameter than the shaft support portion 21, and a stepped surface 47 is provided between the inner cylinder portion 41 and the shaft support portion 21. The roughly ring-shaped circuit board 33 abuts against this stepped surface 47, restricting its position in the direction of the rotation axis Ax.

[0025] The circuit board 33 has a terminal portion 35 to which a winding 32 extending from the stator coil is fixed. This terminal portion 35 is provided in a position corresponding to a protrusion 44. Because a high current is supplied to the winding 32 from the circuit board 33 through this terminal portion 35, it is more prone to generating heat than other parts of the circuit board 33. The terminal portion 35 is mounted on the upstream surface of the circuit board 33. The mounting legs of the terminal portion 35 are provided so as to penetrate the circuit board 33. The mounting legs of the terminal portion 35 protrude from the downstream surface of the circuit board 33, and the protruding portion is soldered. Preferably, the protrusion 44 extending from the bottom plate portion 40 is provided in a position to support the downstream surface of the mounting legs of the terminal portion 35 via a heat transfer pad 60. This allows the circuit board 33 to be cooled efficiently.

[0026] Furthermore, as shown in Figure 1, in the fan 1 of this embodiment, a gap G is provided between the side surface of the circuit board 33 and the inner surface of the bottom plate portion 40. Specifically, a gap G is provided between the side surface of the circuit board 33 and the inner surface of the outer cylindrical portion 42 of the bottom plate portion 40. While fan 1 is operating, air flows through the passage P between the housing 23 and the impeller cup 12. As a result, air is drawn out of the heat dissipation space S between the circuit board 33 and the ring disc portion 43 of the bottom plate portion 40 through the gap G between the side surface of the circuit board 33 and the inner surface of the outer cylinder portion 42 of the bottom plate portion 40. Since the convex portion 44 that receives heat from the circuit board 33 is located in this heat dissipation space S, high-temperature air accumulates in this heat dissipation space S. Therefore, by drawing the high-temperature air out of the gap G between the side surface of the circuit board 33 and the inner surface of the outer cylinder portion 42 of the bottom plate portion 40 into the passage P between the impeller cup 12 and the housing 23, the cooling efficiency of the circuit board 33 by the convex portion 44 is increased.

[0027] Furthermore, in this embodiment, the inner circumference portion 45 of the ring disc portion 43 of the bottom plate portion 40 is positioned upstream of the outer circumference portion 46 in the direction of the rotation axis Ax, thereby reducing the length of the heat dissipation space S in the direction of the rotation axis Ax. As a result, the volume of the heat dissipation space S is small, and the heat dissipation space S can be efficiently ventilated.

[0028] Furthermore, in this embodiment, as shown in Figure 2, a recess 48 is provided on the upstream surface of the bottom plate portion 40, which is recessed in the direction away from the impeller unit 10. The circuit board 33 may be equipped with components that have a larger dimension in the direction of the rotation axis Ax compared to other electronic components such as capacitors. Therefore, a recess 48 may be provided on the surface of the bottom plate portion 40 to avoid these components with a larger dimension in the direction of the rotation axis Ax. This makes it possible to accommodate large components while reducing the heat dissipation space S.

[0029] In this embodiment, a nameplate 70 is attached to the back surface of the base plate 40. The inner circumference 45 recessed from the downstream end to the upstream side of the back surface of the base plate 40 is approximately the same size as the nameplate 70. This makes it easier to align the nameplate 70 when attaching it to the base plate 40. In this embodiment, since the outer peripheral edge 46 on the back surface of the bottom plate 40 is raised, the nameplate 70 attached to the bottom plate 40 is less likely to stick to other components or the user's fingers, making it easier to protect the nameplate 70.

[0030] While embodiments of this disclosure have been described above, it goes without saying that the technical scope of this disclosure should not be interpreted restrictively by the description of these embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications to the embodiments are possible within the scope of the invention described in the claims. The technical scope of this disclosure should be determined based on the scope of the invention described in the claims and the scope of its equivalents. [Explanation of Symbols]

[0031] 1 fan 10 Impeller Units 11 Rotating shaft 12 Impeller Cups 13 Moving blade 20 Frame members 21 Shaft support part 23 Housing 24 stator blades 30 motors 31 Permanent Magnets 32 windings 33 Circuit board 35 Terminal section 40 Bottom plate part 41 Inner cylinder 42 Outer cylinder 43 Ring disc section 44 Convex part 45 Inner circumference 46 Outer edge 47 Step surface 48 recess 50 Bearing section 51 Outer ring 52 Inner Ring 60 Heat Transfer Pads 70 Nameplate 80 Stator Cores

Claims

1. A motor that rotates the impeller unit, The frame member comprises a cylindrical housing, a bottom plate portion provided inside the housing, and a stator blade extending between the bottom plate portion and the housing. The motor's circuit board is provided on the bottom plate portion. A protrusion is provided on the surface of the bottom plate portion on the impeller unit side, which protrudes toward the circuit board. The fan has a bottom plate on its underside where the inner circumference is recessed towards the impeller unit compared to the outer edge.

2. The motor has a stator coil, The circuit board has terminals to which lead wires extending from the stator coil are fixed. The fan according to claim 1, wherein the protrusion is provided at a position corresponding to the terminal portion.

3. The bottom plate portion has an outer cylindrical portion that supports the stator blade, The fan according to claim 1, wherein a gap is formed between the outer cylinder portion and the side surface of the circuit board.

4. The fan according to claim 1, wherein the surface of the bottom plate portion is provided with a recess that is recessed in a direction away from the impeller unit.

5. A nameplate is attached to the back surface of the bottom plate portion. The fan according to claim 1, wherein the inner circumference portion of the base plate is approximately the same size as the nameplate.

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