Patent Description:
<CIT> discloses a waterproof fan. A winding of a motor that drives the fan is covered and molded with resin to enhance the water resistance of the winding in the waterproof fan.

<CIT> relates to a protective structure of a stator and a fan using the same. The protective structure of a stator comprises plural silicon steel sheets, at least one first filler, and a cover body. The silicon steel sheets are surrounded by plural coils. Each of the silicon steel sheets has a hole and plural magnetic poles extending symmetrically outward from the hole. Each of two adjacent magnetic poles defines a space. The first filler is disposed in the spaces. The cover body is disposed to surround the silicon steel sheets such that the cover body, the silicon steel sheets, and the first filler are integrally combined. Therefore, by means of the first filler disposed in the spaces of each of two adjacent magnetic poles, the amount of cover body material can be effectively reduced to further achieve the effect of cost reduction.

The present invention provides a waterproof fan as set out in claim <NUM>. The waterproof fan includes: a rotating blade configured to be rotatable about a rotation axis; a rotor including a permanent magnet; a stator including a plurality of stator cores located on an inner diameter side relative to the rotating blade, the plurality of stator cores extending in a radial direction relative to the rotation axis, and windings each wound around a respective stator core; a circuit board electrically connected to the windings; a waterproof cover including a first resin, the waterproof cover covering the circuit board; and a molded portion including a second resin, the molded portion covering at least the stator. The waterproof cover includes: a partitioning portion separating the windings from the circuit board; and a protruding portion protruding from the partitioning portion into a space between the windings. Gaps between the windings, and the partitioning portion and the protruding portion are filled with the second resin of the molded portion. An inside of the protruding portion is a cavity.

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.

In the waterproof fan described in <CIT>, a space in the surroundings of a board and a space in the surroundings of the winding are filled with waterproofing resin (epoxy resin) to enhance the water resistance of the board and winding.

However, in such a structure, the amount of epoxy resin to be filled increases. Hence, ways of separating the space where the board is housed and the space where the winding is placed with a waterproof cover, and of enhancing the water resistance of the space where the board is housed by use of the waterproof cover while enhancing the water resistance of the winding by filling epoxy resin only in the surroundings of the winding are being examined.

However, the following has been found in the structure using the waterproof cover: When an ambient temperature becomes high or low, since the coefficient of linear expansion of the metal or resin waterproof cover is different from the coefficient of linear expansion of the epoxy resin, thermal stress may be created between the waterproof cover and the epoxy resin to separate the waterproof cover from the epoxy resin.

One object of the present invention is to provide a waterproof fan with high bond strength between a waterproof cover and a waterproofing resin.

A waterproof fan according to the present invention (the present waterproof fan) includes: a rotating blade configured to be rotatable about a rotation axis; a rotor including a permanent magnet; a stator including a plurality of stator cores located on an inner diameter side relative to the rotating blade, the plurality of stator cores extending in a radial direction relative to the rotation axis, and windings each wound around a respective stator core; a circuit board electrically connected to the windings; a waterproof cover including a first resin, the waterproof cover covering the circuit board; and a molded portion including a second resin, the molded portion covering at least the stator. The waterproof cover includes: a partitioning portion separating the windings from the circuit board; and a protruding portion protruding from the partitioning portion into a space between the windings. Gaps between the windings, and the partitioning portion and the protruding portion are filled with the second resin. An inside of the protruding portion is a cavity.

According to the present waterproof fan, it is possible to provide a waterproof fan with high bond strength between a waterproof cover and a resin for water resistance.

An embodiment of the present invention is described hereinafter with reference to the drawings. Descriptions of members having the same reference numerals as members that have already been described in the detailed description are omitted for the convenience of description. Moreover, the dimensions of each member illustrated in the drawings may be different from actual dimensions thereof for the convenience of description.

<FIG> is a front view of a waterproof fan <NUM> according to the embodiment. <FIG> is a front perspective view of a waterproof cover <NUM> (a first cover <NUM>) provided to the waterproof fan <NUM>. In the following description, a reference sign F indicates the front of the waterproof fan <NUM>, and a reference sign B indicates the back of the waterproof fan <NUM>, in the drawings for the sake of convenience.

As illustrated in <FIG>, the waterproof fan <NUM> includes a plurality of (seven in the example) rotating blades W that can rotate about a rotating shaft <NUM> (that is, about a rotation axis A), and a cylindrical casing C that surrounds the periphery of the rotating blades W in the radial direction. The waterproof fan <NUM> rotates the rotating blades W to produce a current of air that flows from one side to the other of the rotation axis A of the rotating shaft <NUM>. In the following description, for the sake of convenience, the one side of the rotation axis A may be referred to as the front F while the other side may be referred to as the back B.

The plurality of rotating blades W is radially attached to the perimeter of a hub portion <NUM>. The hub portion <NUM> is formed in a substantially cup shape, and is provided in such a manner as to surround the rotating shaft <NUM>. The inner structure of a stator <NUM> of the waterproof fan <NUM> illustrated in <FIG> is drawn by broken lines.

The rotating blades W are attached to the hub portion <NUM>. The rotating blades W rotate and produce a current of air between the rotating blades W and the casing C. The rotating blades W are formed in such a manner as to have a shape and structure that produces a current of air from the one side to the other of the rotation axis A. Moreover, the casing C that surrounds the rotating blades W includes a frame portion <NUM> formed in the form of a rectangle, and a circular wind-tunnel portion <NUM> that is defined in the center of the frame portion <NUM> and guides air flow.

<FIG> is a cross-sectional view of the waterproof fan taken along line II-II in <FIG>. <FIG> is a cross-sectional view of the waterproof fan taken along line II-IV in <FIG>.

As illustrated in <FIG> and <FIG>, the waterproof fan <NUM> includes a motor <NUM> that rotationally drives the rotating blades W. The motor <NUM> is provided in the hub portion <NUM> to which the rotating blades W are attached. The motor <NUM> includes, for example, an outer rotor brushless motor. The motor <NUM> includes the stator <NUM>, and a rotor <NUM> that is placed outward of the stator <NUM>.

The rotor <NUM> includes a substantially cup-shaped rotor cover <NUM>, the rotating shaft <NUM>, and permanent magnets <NUM> fixed to the rotor cover <NUM>. The rotating shaft <NUM> is press-fitted by a bush <NUM> in the central part of the rotor cover <NUM>. The rotor cover <NUM> is fitted in the hub portion <NUM>. The hub portion <NUM> where the rotor cover <NUM> is fitted fixes the rotating shaft <NUM> via the bush <NUM>.

The rotor cover <NUM> is mainly made of, for example, a magnetic substance such as a carbon steel casting (SC material). The permanent magnets <NUM> are fastened to an inner peripheral surface of the rotor cover <NUM> along the axial direction in such a manner as to be arranged in the peripheral direction. Magnetic lines of force are confined by the rotor cover <NUM> so that the electromagnetic induction effect increases.

The rotating shaft <NUM> is supported by a bearing <NUM> fixed to a stator frame <NUM> described below, in such a manner as to be rotatable. The bearing <NUM> is fixed to an inner peripheral surface of a tubular bearing holding portion <NUM> formed in the central part of the stator frame <NUM>.

The stator <NUM> includes a plurality of stator cores <NUM> placed on an inner diameter side relative to the rotating blades W, windings <NUM> that are each wound around a respective stator core <NUM>, and the stator frame <NUM>.

The stator frame <NUM> has a substantially cup shape. The stator frame <NUM> and the hub portion <NUM> where the rotating blades W are attached are provided along a direction of the rotation axis A in such a manner that inner sides of the cup shapes are in positions facing each other.

Each of the stator cores <NUM> extends in the radial direction relative to the rotation axis A. The stator core <NUM> is formed by laminating a plurality of thin metal plates in the thickness direction. Examples of the material of the stator core <NUM> include a silicon steel plate.

Each of the stator cores <NUM> is provided outward of the bearing holding portion <NUM> via an insulator <NUM>. The insulator <NUM> includes an upper insulator 43A provided to an upper surface of the stator core <NUM>, and a lower insulator 43B provided to a lower surface of the stator core <NUM>. The upper insulator 43A is provided with an upper inner protruding portion and an upper outer protruding portion that extend in the direction of the rotation axis A. An upper slot 44A is formed between the upper inner protruding portion and the upper outer protruding portion. The lower insulator 43B is also provided with a lower inner protruding portion and a lower outer protruding portion that extend in the direction of the rotation axis A. A lower slot 44B is formed between the lower inner protruding portion and the lower outer protruding portion.

The winding <NUM> is wound around the stator core <NUM>. The winding <NUM> is housed between the upper slot 44A and the lower slot 44B. The upper insulator 43A is located between the winding <NUM> and the upper surface of the stator core <NUM>. Moreover, the lower insulator 43B is located between the winding <NUM> and the lower surface of the stator core <NUM>. Hence, the winding <NUM> is not electrically continuous with the stator core <NUM>. Moreover, the shape of the upper insulator 43A is larger than the stator core <NUM>, and the shape of the lower insulator 43B is larger than the stator core <NUM>, as viewed in the direction of the rotation axis A. Hence, the winding <NUM> located between the upper insulator 43A and the lower insulator 43B is not electrically continuous with the stator core <NUM>, either.

The waterproof fan <NUM> further includes a circuit board <NUM> supported by the stator frame <NUM>, and the waterproof cover <NUM> that covers the circuit board <NUM>.

The circuit board <NUM> is placed behind the stator <NUM>. A wiring pattern for controlling the motor <NUM> is formed on the circuit board <NUM>. The circuit board <NUM> is electrically connected to the windings <NUM> wound around the stator cores <NUM>. A communication terminal <NUM> that is connected to the wiring pattern is soldered to the circuit board <NUM>. The winding <NUM> is connected to the communication terminal <NUM> to electrically connect the circuit board <NUM> to the winding <NUM>. In other words, the communication terminal <NUM> electrically connects the circuit board <NUM> and the winding <NUM>. Although the illustration is omitted, the circuit board <NUM> is connected to a lead wire for supplying power to the waterproof fan <NUM>.

The waterproof cover <NUM> is a waterproof cover that is made of a first resin and covers the circuit board <NUM>. The waterproof cover <NUM> includes the first cover <NUM> that covers the circuit board <NUM> from the front side, and a second cover <NUM> that covers the circuit board <NUM> from the back side. The circuit board <NUM> is housed in a housing space <NUM> formed by the first cover <NUM> and the second cover <NUM>. The waterproof cover <NUM> (the first cover <NUM> and the second cover <NUM>) is mainly made of an electrical insulating synthetic resin (the first resin).

The first cover <NUM> is a cup-shaped member that opens to the back as illustrated in <FIG> and <FIG>. The first cover <NUM> includes a partitioning portion <NUM> that separates the windings <NUM> wound around the stator cores <NUM> from the circuit board <NUM>, and a plurality of (four in this example) protruding portions <NUM> that protrudes frontward from the partitioning portion <NUM>.

The partitioning portion <NUM> is a plate-shaped part that extends along a plane intersecting the rotation axis A. An insertion hole <NUM> where, for example, the rotating shaft <NUM>, the bearing <NUM>, and the bearing holding portion <NUM> are inserted is provided in the central part of the partitioning portion <NUM>. Moreover, a communication hole <NUM> where the communication terminal <NUM> soldered to the circuit board <NUM> is inserted is provided in the periphery of the partitioning portion <NUM>.

The protruding portion <NUM> is a tubular part that extends along the rotation axis A. The protruding portions <NUM> are each provided in such a manner as to protrude into a separate space between the windings <NUM> as viewed in the direction of the rotation axis A and fill the separate space. The protruding portion <NUM> is formed in such a manner that an inside thereof is a cavity <NUM>. In the illustrated example, the protruding portion <NUM> has an isosceles trapezoidal shape in a cross section that traverses the protruding direction.

The first cover <NUM> is attached in such a manner that the communication terminal <NUM> of the circuit board <NUM> is inserted through the communication hole <NUM> of the partitioning portion <NUM> and that each of the protruding portions <NUM> is placed in the separate space between the windings <NUM> that are each wound around the respective stator core <NUM>.

The second cover <NUM> has a shape fitting the shape of the stator frame <NUM> as illustrated in <FIG> and <FIG>. The second cover <NUM> is provided in the cup-shaped stator frame <NUM>. A depression portion <NUM> is formed in the edge of the second cover <NUM>. A projection portion <NUM> formed in the edge of the first cover <NUM> fits in the depression portion <NUM> of the second cover <NUM>. As a result, the waterproof cover <NUM> is formed.

As illustrated in <FIG>, the waterproof cover <NUM> is provided in such a manner that an end 65e, that is on a side farther from the circuit board <NUM> (on the front side), of the protruding portion <NUM> of the first cover <NUM> is located closer to the circuit board <NUM> than (backward of) an end 42e, that is on a side farther from the circuit board <NUM>, of the winding <NUM> wound around the stator core <NUM>.

Moreover, the waterproof fan <NUM> includes a molded portion <NUM> that covers the stator <NUM>, as illustrated in <FIG> and <FIG>. The molded portion <NUM> is mainly made of an electrical insulating synthetic resin (a second resin). The molded portion <NUM> is made of, for example, a thermosetting epoxy resin. The molded portion <NUM> is provided in such a manner as to fill gaps between the windings <NUM> wound around the stator cores <NUM>, and the partitioning portion <NUM> and the protruding portions <NUM> of the first cover <NUM> of the waterproof cover <NUM> to be able to cover at least the stator <NUM>. In other words, the gaps between the windings <NUM>, and the partitioning portion <NUM> and the protruding portions <NUM> are filled with the second resin forming the molded portion <NUM>. The resin forming the molded portion <NUM> is a resin that is different from the resin forming the waterproof cover <NUM> (the first cover <NUM> and the second cover <NUM>).

The resin (second resin) forming the molded portion <NUM> is provided in such a manner as to be less capable of ingress into the housing space <NUM> where the circuit board <NUM> is housed and to cover the surroundings of the stator <NUM>.

Moreover, the resin (second resin) forming the molded portion <NUM> is provided in such a manner as to block the communication hole <NUM> of the first cover <NUM> by entering the communication hole <NUM> from the outside of the waterproof cover <NUM>, surrounding the communication terminal <NUM>, and to slightly protrude from the communication hole <NUM> into the housing space <NUM> along the communication terminal <NUM>. In other words, the second resin forming the molded portion <NUM> is in the housing space <NUM> by entering through the communication hole <NUM> from the outside of the housing space <NUM>.

As described above, in the waterproof fan <NUM> according to the embodiment, the waterproof cover <NUM> includes the partitioning portion <NUM> that separates the windings <NUM> wound around the stator cores <NUM> from the circuit board <NUM>, and the protruding portions <NUM> that protrude from the partitioning portion <NUM> into the spaces between the windings <NUM>. The gaps between the windings <NUM>, and the partitioning portion <NUM> and the protruding portions <NUM> are filled with the synthetic resin (the molded portion <NUM>) to cover the stator <NUM> of the waterproof fan <NUM> with the molded portion.

Consequently, the protruding portions <NUM> can ensure a large contact area between the waterproof cover <NUM> and the molded portion <NUM>. Hence, it is possible to increase the bond strength between the waterproof cover <NUM> and the molded portion <NUM>. Therefore, it is possible to restrain the waterproof cover <NUM> from being separated from the molded portion <NUM> even if thermal stress is created between the waterproof cover <NUM> and the molded portion <NUM> due to the difference between the coefficient of linear expansion of the waterproof cover <NUM> and the coefficient of linear expansion of the molded portion <NUM>.

For example, a method according to which the space between the waterproof cover and the windings of the stator section of the waterproof fan is filled with silicon resin is also used as the method for covering the stator section. However, in the case of this method, it takes time to fill the silicon resin since the space between the waterproof cover and the windings is large. Hence, this method is inferior in production efficiency. In contrast, in the waterproof fan <NUM> according to the embodiment, the protruding portions <NUM> of the waterproof cover <NUM> protrude into the spaces between the windings <NUM> and fill the spaces between the windings <NUM> in advance. Therefore, the amount of silicon resin to be filled can be dramatically reduced. As a result, production efficiency can be increased.

Moreover, in the waterproof fan <NUM>, the protruding portion <NUM> is formed in such a manner that the inside thereof is the cavity <NUM>. Hence, the protruding portion <NUM> has a structure that is susceptible to deformation. Hence, even if the protruding portion <NUM> is pressed by the molded portion <NUM> due to the expansion of the molded portion <NUM>, the protruding portion <NUM> deforms, which enables restraining an excessive force from acting on the protruding portion <NUM> and the molded portion <NUM>. Moreover, the presence of the protruding portions <NUM> reduces the amount of the resin of the molded portion <NUM> to be filled; therefore, it is possible to reduce a force that is produced when the molded portion <NUM> expands. Therefore, an excessive force hardly acts on the winding <NUM>.

Moreover, in the waterproof fan <NUM>, the partitioning portion <NUM> is the plate-shaped part that extends along the plane intersecting the rotation axis A. Moreover, the protruding portion <NUM> is formed in such a manner as to be the tubular part that extends along the rotation axis A. Hence, when the molded portion <NUM> expands and contracts in the direction of the rotation axis A, the partitioning portion <NUM> can easily maintain the joint with the molded portion <NUM>. On the other hand, when the molded portion <NUM> expands and contracts in a direction orthogonal to the rotation axis A, the protruding portion <NUM> can easily maintain the joint with the molded portion <NUM>. In other words, the directions in which the partitioning portion <NUM> and the protruding portion <NUM> extend are different from each other; therefore, whichever direction the molded portion <NUM> expands and contracts, the state where the molded portion <NUM> and the waterproof cover <NUM> are joined can be easily maintained.

Moreover, in the waterproof fan <NUM>, the waterproof cover <NUM> includes the first cover <NUM> having the partitioning portion <NUM> and the protruding portions <NUM>, and the second cover <NUM> that, together with the first cover <NUM>, forms the housing space <NUM> where the circuit board <NUM> is housed. The waterproof cover <NUM> is configured in such a manner as to be less susceptible of the ingress of the molded portion <NUM> into the housing space <NUM> where the circuit board <NUM> is housed. Hence, it is possible to reduce the amount of the synthetic resin to be used for forming the molded portion <NUM>. As a result, the weight of the waterproof fan <NUM> can be reduced.

Moreover, in the waterproof fan <NUM>, the end 65e, that is on the side farther from the circuit board <NUM>, of the protruding portion <NUM> of the first cover <NUM> is provided in such a manner as to be located closer to the circuit board <NUM> than the end 42e, that is on the side farther from the circuit board <NUM>, of the winding <NUM> wound around the stator core <NUM> in the direction of the rotation axis A. Hence, the protruding portion <NUM> placed in the space between the windings <NUM> is located inward of the winding <NUM>. Therefore, when the molded portion <NUM> covers the surface of the stator <NUM>, the surface of the stator <NUM> can be covered in such a manner as to prevent the protruding portion <NUM> from protruding from the molded portion <NUM>. Consequently, it is possible to restrain a gap from being created between the protruding portion <NUM> and the molded portion <NUM>. Therefore, a high water resistance can be ensured.

Moreover, in the waterproof fan <NUM>, the first cover <NUM> is provided with the communication hole <NUM> where the communication terminal <NUM> that electrically connects the circuit board <NUM> and the winding <NUM> is inserted. The resin (second resin) forming the molded portion <NUM> is provided in such a manner as to block the communication hole <NUM> of the first cover <NUM> by entering the communication hole <NUM> from the outside of the waterproof cover <NUM>, and to be slightly in the housing space <NUM>. Consequently, it is possible to establish an electrical connection between the circuit board <NUM> and the winding <NUM> while enhancing the water resistance of the housing space <NUM>.

Up to this point the embodiment of the present invention has been described. In terms of this, it is needless to say that the technical scope of the present invention should not be construed in a limited manner by the description of the embodiment. The embodiment is a mere example. Those skilled in the art understand that the embodiment can be modified in various manners within the technical scope of the present invention which is solely defined by the claims. The technical scope of the present invention is thus solely determined on the basis of the claims.

Claim 1:
A waterproof fan (<NUM>) comprising:
a rotating blade (W) configured to be rotatable about a rotation axis (A);
a rotor (<NUM>) including a permanent magnet (<NUM>);
a stator (<NUM>) including a plurality of stator cores (<NUM>) located on an inner diameter side relative to the rotating blade, the plurality of stator cores extending in a radial direction relative to the rotation axis, and windings (<NUM>) each wound around a respective stator core;
a circuit board (<NUM>) electrically connected to the windings;
a waterproof cover (<NUM>) including a first resin, the waterproof cover covering the circuit board; and
a molded portion (<NUM>) including a second resin, the molded portion covering at least the stator, wherein
the waterproof cover includes:
a partitioning portion (<NUM>) separating the windings from the circuit board; and
a protruding portion (<NUM>) protruding from the partitioning portion into a space between the windings,
wherein gaps between the windings, and the partitioning portion and the protruding portion are filled with the second resin of the molded portion (<NUM>); and
characterized in that an inside of the protruding portion is a cavity (<NUM>).