Waterproof fan

Abstract

To provide a waterproof fan that prevents water from penetrating the circuit board even when thermal stress is repeatedly applied.SOLUTION: A waterproof fan comprises: a rotor 3 having a rotor blade W rotatable around a rotation axis X; a stator 4 having a plurality of stator cores 41 extending radially with respect to the rotation axis X and windings 42 wound around each stator core 41; a frame 5 having a storage space 54 open to a front F; a circuit board 6 electrically connected to the winding 42 and housed in the storage space 54; and a waterproof resin portion 7 covering the stator 4 and the circuit board 6 and blocking the opening of the storage space 54. A positioning member 10 for positioning the circuit board 6 at a position separated from an inner peripheral surface 52a of an outer cylindrical portion 52 is provided in the storage space 54.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a waterproof fan.

Background Art

[0002] Patent Document 1 and the like disclose a waterproof fan in which an electronic component including a circuit board or the like is covered with resin. In the waterproof fan described in Patent Document 1, the circuit board is supported by the frame by abutting a base-side convex portion extending from the frame against the bottom surface of the circuit board. Since this base-side convex portion is provided at a portion outside the radial direction of the waterproof fan, the circuit board can be stably supported.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, since the frame is required to have strength, metal is used. Since the waterproof resin covering the electronic component (including a circuit board or the like) has a significantly different linear expansion coefficient from the metal forming the frame, if repeated thermal stress acts on the waterproof fan, there is a risk that a gap will occur at the interface between the waterproof resin and the frame. Then, there is a risk that water will penetrate through this gap.

[0005] In such a case, in the waterproof fan described in Patent Document 1, since the circuit board is supported by the frame, there is a risk that water will penetrate through the frame from the gap and reach the circuit board.

[0006] Therefore, the present invention provides a waterproof fan in which water hardly penetrates into the circuit board even when repeated thermal stress acts.

Means for Solving the Problems

[0007] The waterproof fan according to one aspect of the present invention is a rotor having a rotating blade rotatable around a rotation axis, a stator having a plurality of stator cores extending in a radial direction with respect to the rotation axis, and windings wound around each of the stator cores, a frame having an accommodation space opened on one side of the rotation axis, a circuit board electrically connected to the winding and accommodated in the accommodation space, and a waterproof resin part covering the stator and the circuit board and closing the opening of the accommodation space. A positioning member is provided in the accommodation space for positioning the circuit board at a position spaced apart from the inner wall of the accommodation space.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide a waterproof fan in which water hardly enters the circuit board even when thermal stress repeatedly acts.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the embodiments, for the members having the same reference numerals as the members already described, the description thereof will be omitted for the sake of convenience. Also, the dimensions of each member shown in the drawings may be different from the actual dimensions of each member for the sake of convenience.

[0011] FIG. 1 is a front view of a waterproof fan 1 according to an embodiment of the present invention. As shown in FIG. 1, the waterproof fan 1 includes a plurality (five in the example shown in the figure) of rotating blades W rotatable about the axis of the rotating shaft portion 20, and a cylindrical casing C surrounding the outer periphery of the rotating blades W. The waterproof fan 1 generates an air flow flowing from one side to the other side in the direction of the axis of the rotating shaft portion 20 (front-back direction in the figure) by the rotation of the rotating blades W. In the following description, for convenience, the direction of the axis of the rotating shaft portion 20 may be referred to as the direction of the "rotating axis X". Also, the direction orthogonal to the rotating axis X may be referred to as the "radial direction".

[0012] The plurality of rotating blades W are radially attached around the impeller 21. The impeller 21 is formed in a substantially cup shape and is provided so as to surround the periphery of the rotating shaft portion 20. In the waterproof fan 1 shown in FIG. 1, the inside of the stator 4 is drawn with a broken line.

[0013] The rotating blades W attached to the impeller 21 generate an air flow between the rotating blades W and the casing C by the rotation of the rotating blades W. The rotating blades W are formed in a shape and structure that generates an air flow from one side to the other side of the rotating axis X. Also, the casing C surrounding the rotating blades W has a frame portion 22 formed in a rectangular shape, and a circular wind tunnel portion 23 partitioned in the center of the frame portion 22 for guiding the air flow.

[0014] FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1. In the following description, for convenience, one side of the rotating axis X may be referred to as the front F, and the other side opposite to one side of the rotating axis X may be referred to as the rear B.

[0015] As shown in FIG. 2, the waterproof fan 1 includes a motor 2 for rotationally driving the rotating blades W. The motor 2 is provided inside the impeller 21 to which the rotating blades W are attached. The motor 2 is composed of, for example, an outer rotor type brushless motor. The motor 2 has a stator 4 and a rotor 3 disposed on the outer periphery of the stator 4. In FIG. 2, the rotor 3 is shown in a simplified notation.

[0016] The rotor 3 includes a substantially cup-shaped rotor cover 31, a rotating shaft portion 20 press-fitted into the central portion of the rotor cover 31 by a bush (not shown), and a permanent magnet 33 fixed to the rotor cover 31.

[0017] The rotor cover 31 is fitted into the impeller 21. The impeller 21 into which the rotor cover 31 is fitted is fixed to the rotating shaft portion 20 via a bush (not shown). The rotor cover 31 is made of a magnetic material such as carbon steel cast steel (SC material), for example. Permanent magnets 33 are fixed to the inner peripheral surface of the rotor cover 31 in the radial direction so as to be arranged in the circumferential direction. The rotor cover 31 closes magnetic field lines to enhance the electromagnetic induction effect.

[0018] The rotating shaft portion 20 is rotatably supported by bearings 24 (a first bearing 24a and a second bearing 24b). The bearings 24 are fixed to a cylindrical inner cylinder portion 51 formed at the central portion of a frame 5 described later.

[0019] The stator 4 includes a plurality of stator cores 41 arranged radially inside the rotating blades W, and windings 42 wound around each of the stator cores 41.

[0020] Each stator core 41 extends radially with respect to the rotation axis X. The stator core 41 is formed by laminating a plurality of thin metal plates in the plate thickness direction. As the material of the stator core 41, for example, a silicon steel sheet is used.

[0021] Each stator core 41 is provided on the outer peripheral side in the radial direction of the inner cylinder portion 51 via an insulator 43. The insulator 43 is composed of a front insulator 43A provided on the front F surface of the stator core 41 and a rear insulator 43B provided on the rear B surface of the stator core 41. The front insulator 43A is provided with a front inner protruding portion and a front outer protruding portion extending in the direction of the rotation axis X. A front slot 44A is formed between the front inner protruding portion and the front outer protruding portion. The rear insulator 43B is also provided with a rear inner protruding portion and a rear outer protruding portion extending in the direction of the rotation axis X. A rear slot 44B is formed between the rear inner protruding portion and the rear outer protruding portion.

[0022] The winding 42 is wound around the stator core 41. The winding 42 is housed between the front slot 44A and the rear slot 44B. The front insulator 43A is located between the winding 42 and the front surface of the stator core 41, and the rear insulator 43B is located between the winding 42 and the rear surface of the stator core 41, so that the winding 42 is not electrically connected to the stator core 41. In addition, when viewed from the direction of the rotation axis X, the shape of the front insulator 43A is larger than the shape of the stator core 41, and the shape of the rear insulator 43B is larger than the shape of the stator core 41. Therefore, the winding 42 located between the front insulator 43A and the rear insulator 43B is also not electrically connected to the stator core 41.

[0023] The waterproof fan 1 further includes a frame 5 and a circuit board 6 housed in the frame 5.

[0024] The frame 5 is provided at a rear B position of the waterproof fan 1. The frame 5 is generally cup-shaped. The frame 5 is provided along the direction of the rotation axis X with the insides of the cup shapes facing each other, together with the impeller 21 to which the rotor blades W are attached.

[0025] The frame 5 has an inner cylinder portion 51 provided on the radially inner side, an outer cylinder portion 52 having a larger diameter than the inner cylinder portion 51 and provided on the radially outer side, and a bottom portion 53 provided at the rear B and connecting the inner cylinder portion 51 and the outer cylinder portion 52. The frame 5 has an accommodation space 54 constituted by the inner cylinder portion 51, the outer cylinder portion 52, and the bottom portion 53 for accommodating the circuit board 6.

[0026] The inner cylinder part 51 is provided so as to continuously extend forward F from the inner end in the radial direction of the bottom part 53. The inner cylinder part 51 has a small-diameter part 51a and a large-diameter part 51b. The small-diameter part 51a is a part that constitutes the part of the inner cylinder part 51 closer to the front F. The large-diameter part 51b is a part that constitutes the part of the inner cylinder part 51 closer to the rear B and has a larger diameter than the small-diameter part 51a. At the boundary between the small-diameter part 51a and the large-diameter part 51b, a stepped part 51c is formed due to the difference in the diameters of both parts. The stepped part 51c is formed on the outer side in the radial direction of the inner cylinder part 51.

[0027] The small-diameter part 51a of the inner cylinder part 51 is inserted through the central part of the stator 4. Bearings 24 (first bearing 24a, second bearing 24b) for supporting the rotating shaft part 20 are fixed to the inner peripheral surface 51d in the radial direction of the small-diameter part 51a. Further, on the outer side in the radial direction of the small-diameter part 51a, the stator core 41 of the stator 4 is arranged.

[0028] The outer cylinder part 52 is provided so as to continuously extend forward F from the outer end in the radial direction of the bottom part 53. In the example shown in the figure, the outer cylinder part 52 is formed such that the height extending forward F is lower than the height of the inner cylinder part 51. The height of the outer cylinder part 52 is formed to be at least higher than the height of the stepped part 51c formed on the inner cylinder part 51.

[0029] The bottom part 53 is provided so as to expand in the radial direction from the outer peripheral surface in the radial direction of the inner cylinder part 51 to the inner peripheral surface in the radial direction of the outer cylinder part 52. The bottom part 53 is provided so as to cover the rear B of the stator 4.

[0030] The accommodation space 54 is constituted by the outer peripheral surface 51e in the radial direction of the inner cylinder part 51 including the small-diameter part 51a and the large-diameter part 51b, the front F surface 53a of the bottom part 53, and the inner peripheral surface 52a in the radial direction of the outer cylinder part 52. The front F surface 53a of the bottom part 53 constitutes the bottom surface 53a of the accommodation space 54. The accommodation space 54 is a space that opens forward F. The accommodation space 54 is a space that opens toward the stator 4.

[0031] The accommodation space 54 is provided with a positioning member 10 for positioning the circuit board 6 to be accommodated. The positioning member 10 is made of resin. The positioning member 10 is provided so as to fill a partial area at the rear B of the accommodation space 54, that is, so as to cover the bottom surface 53a of the accommodation space 54. The positioning member 10 has a base portion 11 provided in contact with the bottom surface 53a of the accommodation space 54, and a protruding portion 12 extending forward F from the base portion 11.

[0032] The protruding portion 12 extends forward F from the outer end portion in the radial direction of the base portion 11. The protruding portion 12 is provided such that the rear portion 12b at the rear B contacts the inner peripheral surface 52a of the outer cylinder portion 52, and the front portion 12f at the front F is provided in a state of being separated from the inner peripheral surface 52a of the outer cylinder portion 52. In the example shown in the figure, a gap 55 is formed between the front portion 12f of the protruding portion 12 and the inner peripheral surface 52a of the outer cylinder portion 52. The protruding portion 12 is provided such that the tip portion at the front F of the front portion 12f is at the same position as the step portion 51c of the inner cylinder portion 51, or extends forward F beyond the step portion 51c.

[0033] The circuit board 6 is supported in the accommodation space 54 by the step portion 51c of the inner cylinder portion 51 and the front portion 12f of the protruding portion 12 of the positioning member 10. The circuit board 6 is disposed behind the stator 4. The circuit board 6 is formed in a circular shape. An opening through which the inner cylinder portion 51 of the frame 5 can be inserted is provided at the central portion of the circuit board 6. The inner side portion in the radial direction of the circuit board 6 is supported by the step portion 51c of the inner cylinder portion 51, and the outer side portion in the radial direction of the circuit board 6 is supported by the front portion 12f of the protruding portion 12 of the positioning member 10.

[0034] The circuit board 6 is positioned in the direction of the rotation axis X by the stepped portion 51c of the inner cylinder portion 51. Also, the circuit board 6 is positioned radially by the front portion 12f of the protruding portion 12 of the positioning member 10. The outer portion of the circuit board 6 in the radial direction is positioned at a position spaced apart from the inner peripheral surface 52a of the outer cylinder portion 52 by the front portion 12f of the protruding portion 12 of the positioning member 10. A wiring pattern for controlling the waterproof fan 1 is formed on the circuit board 6. The circuit board 6 is electrically connected to the winding 42 wound around the stator core 41.

[0035] Figure 3 is a cross-sectional view along the radial direction passing through the circuit board 6 of the waterproof fan 1. As shown in FIG. 3, a fitted portion 61 formed as, for example, a concave groove is provided at the outer edge of the circuit board 6. The positioning member 10 for positioning the circuit board 6 fits into the fitted portion 61. The positioning member 10 is provided with a fitting portion 13 that fits into the fitted portion 61 of the circuit board 6 at the tip of the front portion 12f of the protruding portion 12. The fitting portion 13 is formed in a shape corresponding to the concave groove of the fitted portion 61.

[0036] When the fitting portion 13 of the positioning member 10 fits into the fitted portion 61 of the circuit board 6, the position of the outer portion of the circuit board 6 in the radial direction is positioned by the positioning member 10. The outer portion of the circuit board 6 in the radial direction is positioned at a position spaced apart from the inner peripheral surface 52a of the outer cylinder portion 52 by a gap 55.

[0037] Returning to FIG. 2, the waterproof fan 1 further includes a waterproof resin portion 7 that covers the stator 4 and the circuit board 6. The waterproof resin portion 7 is composed of an electrically insulating synthetic resin. For example, the waterproof resin portion 7 is composed of a thermosetting epoxy resin.

[0038] The waterproof resin part 7 closes the opening of the accommodation space 54 by filling resin so as to cover the stator 4 and the circuit board 6. The resin of the waterproof resin part 7 is filled in the accommodation space 54, such as the gap between the circuit board 6 and the stator 4, the gap between the circuit board 6 and the positioning member 10, and the gap 55 between the front part 12f of the protruding part 12 of the positioning member 10 and the inner peripheral surface 52a of the outer cylinder part 52.

[0039] The resin constituting the waterproof resin part 7 and the resin constituting the positioning member 10 are made of different resins.

[0040] By the way, the resin used for the waterproof resin part 7 is often made of a material different from that of the frame. When the materials are different, due to the difference in the linear expansion coefficient, a gap is generated between the waterproof resin part and the frame as the ambient temperature changes. This is likely to occur especially when the frame is made of a metal material. When a gap is generated between the waterproof resin and the frame, there is a risk that water may enter from the outside into the gap and reach the circuit board.

[0041] On the other hand, in the waterproof fan 1 according to the present embodiment, a positioning member 10 for positioning the circuit board 6 at a position separated from the inner peripheral surface 52a of the outer cylinder part 52 is provided in the accommodation space 54. According to this configuration, the positioning member 10 for positioning the circuit board 6 is provided as a separate member from the frame 5 in the accommodation space 54 of the frame 5. And the circuit board 6 accommodated in the accommodation space 54 is positioned separated from the inner wall of the accommodation space 54 by the positioning member 10. Therefore, when a gap is generated between the frame 5 and the waterproof resin part 7 as the ambient temperature changes, the water that penetrates through the frame 5 from the gap can be made not to reach the circuit board 6, for example, as shown by the arrow D in FIG. 2. In the illustrated example, among the positioning members 10, the fitting part 13 provided at a position separated from the inner peripheral surface 52a of the outer cylinder part 52 positions the circuit board 6.

[0042] Also, according to the waterproof fan 1, the frame 5 has an inner cylinder portion 51 that supports the bearing 24, an outer cylinder portion 52 that has a larger diameter than the inner cylinder portion 51 and extends forward F from the radially outer end of the bottom portion 53, and a bottom portion 53 that connects the inner cylinder portion 51 and the outer cylinder portion 52 at the rear B and constitutes the bottom surface of the accommodation space 54. And the accommodation space 54 is constituted by the outer peripheral surface 51e of the inner cylinder portion 51, the bottom surface 53a in front F of the bottom portion 53, and the inner peripheral surface 52a of the outer cylinder portion 52. Thereby, the circuit board 6 can be accommodated so as to surround it within the accommodation space 54 that opens forward F.

[0043] Also, according to the waterproof fan 1, the inner cylinder portion 51 has a small-diameter portion 51a inserted through the stator 4 and a large-diameter portion 51b that has a larger diameter than the small-diameter portion 51a and is located rearward B of the small-diameter portion 51a. And the circuit board 6 is positioned in the direction of the rotation axis X by the step portion 51c between the small-diameter portion 51a and the large-diameter portion 51b, and is positioned in the circumferential direction of the rotation axis X by the positioning member 10. Thereby, the circuit board 6 can be positioned from the front, rear, left, and right directions, and it becomes possible to accurately position the circuit board 6.

[0044] Generally, in the motor 2 portion composed of the rotor 3 and the stator 4, since the stator 4 is provided in the radially inner region, water is less likely to penetrate. In contrast, water is likely to penetrate into the radially outer region. Also, regarding the positioning of the members used in the motor 2, the positioning accuracy is higher when positioning is performed on the radially outer side. In contrast, according to the waterproof fan 1 of the present embodiment, the fitting portion 13 provided at the front portion 12f of the protruding portion 12 of the positioning member 10 that is separated from the inner peripheral surface 52a of the outer cylinder portion 52 of the frame 5 fits into the fitted portion 61 provided on the outer edge of the circuit board 6, whereby the positioning member 10 positions the circuit board 6. For this reason, the waterproof performance with respect to the circuit board 6 can be enhanced, and the positioning accuracy of the circuit board 6 can be enhanced.

[0045] Further, according to the waterproof fan 1, the positioning member 10 has a base portion 11 that contacts the bottom surface 53a of the accommodation space 54, and a protruding portion 12 that extends forward F from the base portion 11. The positioning member 10 is provided such that the base portion 11 covers the bottom surface 53a of the accommodation space 54 and fills a partial region at the rear B of the accommodation space 54, and the protruding portion 12 extending forward F supports the circuit board 6. In this way, by providing the positioning member 10 in the accommodation space 54, the amount of the waterproof resin filled in the accommodation space 54 can be reduced, so that the filling time and the curing time of the waterproof resin can be shortened.

[0046] Further, according to the waterproof fan 1, the positioning member 10 is made of a resin different from that of the waterproof resin portion 7. The waterproof resin portion 7 is formed by filling a liquid waterproof resin. For this reason, the waterproof resin is required to have characteristics that are easy to fill. On the other hand, since such a requirement is not imposed on the positioning member 10, for example, an inexpensive resin can be used. In this way, since the resin of the waterproof resin portion 7 and the resin of the positioning member 10 can be made different, the degree of freedom in material selection can be increased.

[0047] As described above, the embodiments of the present invention have been described. Needless to say, the technical scope of the present invention should not be construed in a limited manner by the description of the present embodiment. This embodiment is merely an example, and it is understood by those skilled in the art that various modifications of the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and the equivalent scope thereof.

Explanation of reference numerals

[0048] 1 Waterproof fan 2 Motor 3 Rotor 4 Stator 5 Frame 6 Circuit board 7 Waterproof resin portion 10 Positioning member 11 Base portion 12 Protruding portion Rear part of 12b Front part of 12f Fitting part 13 Rotating shaft part 20 Impeller 21 Bearing 24 Stator core 41 Winding 42 Inner cylinder part 51 Small-diameter part 51a Large-diameter part 51b Step part 51c Inner peripheral surface 51d Outer peripheral surface 51e Outer cylinder part 52 Inner peripheral surface 52a Bottom part 53 Bottom surface 53a Accommodation space 54 Gap 55 Fitted part 61 Rotating blade W Rotation axis line X

Claims

1. A rotor having a rotating blade rotatable about a rotation axis, A stator having a plurality of stator cores extending in a radial direction with respect to the rotation axis, and windings wound around each of the stator cores, A frame having an accommodation space opened on one side of the rotation axis, A circuit board electrically connected to the winding and accommodated in the accommodation space, A waterproof resin part covering the stator and the circuit board and closing the opening of the accommodation space, and A waterproof fan provided with a positioning member for positioning the circuit board at a position spaced apart from the inner wall of the accommodation space in the accommodation space.

2. The waterproof fan according to claim 1, wherein the positioning member is made of a resin different from the waterproof resin part.

3. The waterproof fan according to claim 1, wherein the positioning member positions the circuit board by fitting a fitting part provided on the positioning member into a fitted part provided on the outer edge of the circuit board.

4. The accommodation space has a bottom surface on the other side of the rotation axis, The positioning member is, A base part in contact with the bottom surface of the accommodation space, A protruding part extending from the base part to one side of the rotation axis, and The waterproof fan according to claim 1, wherein the protruding part is in contact with the circuit board.

5. The rotor has a rotating shaft part supported by a bearing, The frame is, An inner cylinder part supporting the bearing, An outer cylinder part having a larger diameter than the inner cylinder part, A bottom part connecting the inner cylinder part and the outer cylinder part on the other side of the rotation axis and constituting the bottom surface of the accommodation space, and The outer cylinder part extends from a radial end part of the bottom part to one side of the rotation axis, The waterproof fan according to claim 1, wherein the accommodation space is constituted by an outer peripheral surface of the inner cylinder part, a surface of the bottom part on one side of the rotation axis, and an inner peripheral surface of the outer cylinder part.

6. The inner cylinder part is, A small-diameter part inserted through the stator, A large-diameter part having a larger diameter than the small-diameter part and located on the other side of the rotation axis than the small-diameter part, and The waterproof fan according to claim 5, wherein the circuit board is positioned in the direction of the rotation axis by a step part between the small-diameter part and the large-diameter part and is positioned in the circumferential direction of the rotation axis by the positioning member.

7. The positioning member has a base part in contact with the bottom surface of the accommodation space and a protruding part extending from the base part to one side of the rotation axis. The waterproof fan according to claim 1, wherein the protruding portion supports the circuit board.

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