Molding structure of brushless fan motor and molding method thereof

Abstract

The present invention provides a molding structure of a brushless fan motor and a molding method thereof. In the molding structure of the brushless fan motor, at least a portion of a circuit substrate is carried on a notch at the top end of a protruding end formed on the substrate storage portion side and the rotating shaft side of an insulator, the substrate storage portion and the insulator are arranged to surround the periphery of a bearing support cylinder portion, a portion of the molding portion is sandwiched between the bearing support cylinder portion and the insulator and between the substrate storage portion and the insulator, and the entire circuit substrate located inside the storage chamber, except for a portion of the protruding end formed on the substrate storage portion side of the insulator, is covered by a portion of the molding portion.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on Japanese Patent Application No. 2019-051117 filed with the Japan Patent Office on March 19, 2019, and all the contents of the Japanese Patent Application are hereby incorporated by reference. Technical Field

[0003] One aspect of the present invention relates to a molding structure of a brushless fan motor and a molding method thereof. Background Art

[0004] Conventional brushless fan motors also have the following structure. In this structure, silicone rubber is used to mold the wire storage groove in the connector that stores the stator and wires in the stator side housing. As a result, the stator side has a waterproof structure. It is known that if such conventional brushless fan motors are used for a long time in an environment containing oil mist and moisture, the insulation of the molded part will deteriorate or the rotor will become difficult to rotate. Therefore, the use of Figure 4 In this structure, a stator, a circuit board including electronic components, and a plurality of lead wires are molded with a resin material such as epoxy resin while being housed in a stator-side housing (see, for example, Japanese Patent Gazette No. 3730461).

[0005] In this conventionally known molding structure, epoxy resin has a strong tolerance to moisture or oil (and mist and emulsion containing these. The same applies hereinafter). Therefore, even if the parts molded by epoxy resin are exposed to moisture or oil for a long time, there is little possibility of expansion and reduction of insulation. In addition, due to the expansion of the molded part, the gap size between the rotor and the stator becomes smaller, thereby reducing the possibility of hindering the rotation of the rotor.

[0006] In particular, it is useful to select a specific resin material having a certain hardness (e.g., epoxy resin having a hardness of Shore D30 to Shore D90 after curing) from the following viewpoints: that is, the molding accuracy and mechanical strength of the molded part can be maintained, and the stress applied to the electronic components and circuit boards arranged inside the molded part can be reduced. Therefore, an effective waterproof and oil-proof structure can be obtained.

[0007] In the past, we understood that by adopting Figure 4The molded structure shown prevents corrosion, erosion and other insulation breakdown of circuit substrates and the like caused by moisture or oil. However, the inventors have discovered that the following may occur. Even if the molded structure described above is used, an interface between different materials such as metal materials and resin materials still exists in a part of the molded structure. The tiny gap formed at the interface attracts and enters moisture or oil from the outside due to the capillary phenomenon. The moisture or oil forms a path to the circuit substrate buried inside the molded structure. The moisture or oil that enters through the path reaches the circuit substrate. As a result, corrosion, erosion and other insulation breakdown of the circuit substrate occur.

[0008] That is, in Figure 4 In the example shown, the circuit board 4 is waterproof and oil-proofed by a molded portion made of thermosetting resin. The outer peripheral surface of the bearing support cylinder 17 of the bearings 15 and 16 supporting the rotating shaft 13 is tightly surrounded by the stator core 2, the insulator (no reference numeral) wound around the stator coil 3, and the substrate storage portion (frame) 19 made of thermoplastic resin. The end edge of the circuit board 4 on the rotating shaft 13 side is embedded in the cutout at the top end of the protruding end of the insulator. The end edge of the circuit board 4 on the rotating shaft 13 side is clamped by the substrate storage portion (frame) 19 at the step portion formed by the cutout.

[0009] In this structure, the substrate storage portion (frame) 19 and the bearing support cylinder 17 are made of different materials. Therefore, due to the capillary phenomenon generated by the small gap (interface) between the substrate storage portion (frame) 19 and the bearing support cylinder 17, as shown by the arrows in the figure, moisture or oil is sucked in and enters from the external environment (atmosphere). The moisture or oil that enters in the above manner reaches the circuit substrate 4 through the small gap (interface) between the components that are also made of different materials. If a long time passes, there is a possibility that corrosion, erosion and other poor insulation of the circuit substrate 4 will occur.

[0010] In addition, strictly speaking, even between parts made of the same material, there is a small gap, except when they are integrated by alloying such as welding. Therefore, the same phenomenon may occur in this case. However, it is considered that when the parts are made of different materials, the above phenomenon is likely to increase during the use of the brushless fan motor due to differences in thermal expansion coefficient, time change, or the degree of expansion of water or oil. Summary of the invention

[0011] An object of the present invention is to provide a molded structure of a brushless fan motor. In the molded structure of the brushless fan motor, the influence of the ingress of water or oil can be reduced. In addition, the molded structure can maintain durability even when used for a long time, and has higher water resistance and oil resistance than before.

[0012] In addition, another object of the present invention is to provide a molding method of the above-mentioned brushless fan motor.

[0013] A molded structure of a brushless fan motor according to one embodiment of the present invention (the present molded structure) comprises: a stator, which is composed of a core composed of a plurality of stacked steel plates and having a plurality of salient pole portions, the salient pole portions of the core being wound with slot coils by means of slots of an insulator arranged around the core, and has a plurality of stator poles; a circuit substrate fixed to the stator, on which are mounted electronic components constituting a control circuit, the control circuit being used to control current flowing in the coils constituting the plurality of stator poles; a rotor, which has a plurality of rotor poles constituted by permanent magnets on the inner circumference and a plurality of blades on the outer circumference; and a stator-side housing, comprising: a bearing-supporting cylinder portion which internally accommodates a bearing that supports the rotating shaft of the rotor so as to be rotatable; a shell portion surrounding the outer circumference of the blades of the rotor; and an inner and outer circumference of the circuit substrate and the rotor except for the rotor side. The molded portion is formed by molding at least the stator and the circuit substrate including the electronic components through an insulating material, and at least a portion of the circuit substrate is carried on a cutout at the top end of a protruding end formed on the substrate housing portion side of the insulator and on the rotating shaft side. The substrate housing and the insulator are configured to surround the bearing support cylinder, and a portion of the molded portion is sandwiched between the bearing support cylinder and the insulator, and between the substrate housing and the insulator. The entire circuit substrate located inside the storage chamber is covered by a portion of the molded portion except for a portion of the protruding end formed on the substrate housing portion side of the insulator.

[0014] The present molded structure, by adopting the above structure, has the following functions and effects in addition to the functions obtained by the molded structure of the conventional brushless fan motor. That is, in the present molded structure, the entire circuit substrate is covered by a part of the molded portion. Therefore, even if liquid such as water or oil enters due to the capillary phenomenon in the interface between different substances such as metal material and resin material remaining in a part of the molded structure, the entered water or oil is difficult to reach the circuit substrate.

[0015] Furthermore, in the present molding structure, a small diameter portion may be formed on the outer peripheral portion of the bearing support cylinder portion by means of a step, and a jaw portion abutting against the step and engaging with the small diameter portion is formed on the inner peripheral side of the insulator, the jaw portion being formed so that the height of the jaw portion relative to the surface of the inner peripheral side of the insulator is greater than the depth of the step, and a portion of the molding portion is sandwiched between the bearing support cylinder portion and the insulator.

[0016] Furthermore, in the present mold structure, the surface where the step and the jaw portion abut against each other may be a positioning portion that suppresses movement of the insulator and the stator toward the substrate housing portion or a dam portion that suppresses passage of liquid.

[0017] In the prior art, the stator and the insulator are positioned in the direction of the rotation axis by abutting each other between the top end of the insulator and the substrate storage portion (frame) near the portion that carries the circuit substrate. On the other hand, in the present molded structure having the above-mentioned structure, a positioning portion in the direction of the rotation axis can be formed between the outer periphery of the bearing support cylinder and the inner peripheral side edge of the insulator. Therefore, it is possible to suppress the entry of moisture or oil from reaching the circuit substrate, and the insulator and the stator can be positioned in the direction of the rotation axis without obstacles. In addition, a cofferdam portion that suppresses the further flow of liquid entering from the outside to the inside can be formed between the outer periphery of the bearing support cylinder and the inner peripheral side edge of the insulator. Therefore, the entry of moisture or oil can be effectively suppressed. In addition, regarding the role of the positioning portion or the cofferdam portion, the present molded structure can be constructed to play the role of either or both.

[0018] In addition, a molding method of a brushless fan motor according to one embodiment of the present invention (the present molding method) is the molding method of the brushless fan motor described above. The present molding method at least includes: preparing the insulator holding the circuit substrate and the stator assembly including the stator; embedding the stator assembly in a predetermined position of the bearing support cylinder in such a manner that the circuit substrate is located inside the substrate storage portion; using a mold having a gate for injecting the insulating material for molding to surround the molded portion including at least the stator assembly; and forming the molded portion by injecting the insulating material for molding from the gate of the mold.

[0019] Furthermore, in the present molding method, the stator assembly may be embedded in a predetermined position of the bearing support cylinder, including positioning the stator assembly by abutting a step forming a small diameter portion on the outer periphery of the bearing support cylinder against a jaw portion on the inner periphery of the insulator.

[0020] In this molding method, the circuit board, the insulator, and the stator assembly including the core can be positioned in the direction of the rotation axis. Therefore, the insulator and the stator assembly including the core are less likely to be misaligned during the molding process.

[0021] Furthermore, according to the matters described in each of the claims of the appended claims, it is possible to provide an excellent molding structure of a brushless fan motor and a molding method thereof.

[0022] According to the present invention, corrosion, erosion and other poor insulation phenomena of the circuit substrate caused by the intrusion of moisture or oil can be suppressed. Therefore, a brushless fan motor having higher waterproof and oil-proof properties than before and capable of maintaining durability even in long-term use can be obtained.

[0023] Furthermore, in the molding process of the brushless fan motor, the brushless fan motor can be manufactured easily and with high precision, so that a brushless fan motor with excellent performance can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a half cross-sectional view of a brushless fan motor according to an embodiment of the present invention as viewed from a plane that is parallel to the rotation shaft and passes through the center of the rotation shaft.

[0025] Figure 2 yes Figure 1 An enlarged view of a portion of the brushless fan motor where an entry path for moisture, oil, etc. is blocked by a molding material is shown.

[0026] Figure 3 A~C is Figure 1 The half cross-sectional view of the brushless fan motor shown is a view of the brushless fan motor viewed from a plane parallel to the rotation shaft and passing through the center of the rotation shaft, and shows the state of the brushless fan motor in each step of the molding process of the brushless fan motor.

[0027] Figure 4 This is a half-section view of a conventional brushless fan motor, showing the structure of the brushless fan motor and indicating the entry path of moisture, oil, etc. with arrows. DETAILED DESCRIPTION

[0028] In the detailed description below, for the purpose of illustration, in order to provide a thorough understanding of the disclosed embodiments, many specific details are set forth. However, it is apparent that one or more embodiments may be implemented without these specific details. In other cases, in order to simplify drawing, well-known structures and devices are schematically shown.

[0029] Figure 1 FIG. 1 is a half-section view of a brushless fan motor according to an embodiment of the present invention viewed from a direction parallel to the central axis. Figure 1 In the figure, the component indicated by reference numeral 1 is a stator assembly. The stator assembly 1 includes a stator core 2 formed by stacking a plurality of silicon steel plates. The stator core 2 has a plurality of salient pole portions 2a arranged in a circumferential direction. In addition, an insulator 32 is provided on each salient pole portion 2a of the stator core 2, and the insulator 32 has slots that constitute a space for winding the stator coil 3. The stator is formed by winding the stator coil 3 as a slot coil with the aid of the above-mentioned slots. Since the stator coil 3 is excited, these multiple salient pole portions 2a function as stator poles. Therefore, the top of each salient pole portion 2a becomes the pole face 2b of the stator pole. The component indicated by reference numeral 4 is a circuit substrate fixed to the stator. Electronic components constituting a control circuit are mounted on the circuit substrate 4. The control circuit is a circuit for controlling the current flowing in the stator coil 3 that is a part of the multiple stator poles constituting the stator assembly 1. The control circuit on the circuit board 4 and the stator coil 3 are electrically connected by winding the conductive wire of the stator coil 3 around terminal pins (pin portions) 5 that pass through through holes 4 a of the circuit board 4 and are soldered to electrodes on the circuit board 4 .

[0030] The component indicated by reference numeral 6 is a rotor assembly, i.e., a rotor. The rotor assembly 6 includes a rotor side housing 7. The rotor side housing 7 includes a cup member 8 containing a magnetically conductive material and a blade mounting hub 9 fitted into the outer periphery of the cup member 8. The cup member 8 includes a cylindrical portion 8a and a bottom wall portion 8b closing one end of the cylindrical portion 8a. A plurality of rotor poles 10 containing permanent magnets are arranged and fixed in the circumferential direction on the inner periphery of the cylindrical portion 8a. A through hole 8c is formed at the center of the bottom wall portion 8b, into which a sleeve 11 described later is fitted. The blade mounting hub 9 includes a cylindrical portion 9a and a bottom wall portion 9b closing one end of the cylindrical portion 9a. A plurality of blades 12 are fixed to the outer periphery of the cylindrical portion 9a. A sleeve 11 is fixed to the central portion of the bottom wall portion 9b. The sleeve 11 is used to fix the rotor side housing 7 to the rotating shaft 13.

[0031] In addition, of course, the specification elements such as the cross-sectional shape, the angle of attack, and the torsion angle in the blade can be arbitrarily selected to be appropriate values ​​corresponding to the specifications of the brushless fan motor.

[0032] The component indicated by reference numeral 14 is a stator-side housing. The stator-side housing 14 includes: a bearing support cylinder 17, a shell 18, a substrate storage portion 19, and a plurality of connectors 20. Two bearings 15 and 16 that support the rotating shaft 13 of the rotor assembly 6 so that it can rotate freely are stored inside the bearing support cylinder 17. The shell 18 surrounds the outer periphery of the plurality of blades 12 of the rotor assembly 6. The substrate storage portion 19 covers the inner and outer peripheral sides of the circuit substrate 4 except for the portion on the rotor assembly 6 side and the opposite side of the rotor assembly 6. The substrate storage portion 19 forms a storage chamber 38 for storing and configuring the circuit substrate 4. A plurality of connectors 20 connect the substrate storage portion 19 and the shell 18. A plurality of connectors 20 (see Figure 4 . Figure 1 to Figure 3 (not shown) are arranged at intervals along the circumferential direction. Figure 4 As in the prior art shown, one of the plurality of connectors 20 is formed with a wire receiving groove 22. The wire receiving groove 22 receives a plurality of wires 21 extending from and connected to the control circuit of the circuit board 4 and guides them toward the housing 18. A communication passage 23 is formed between the wire receiving groove 22 and the board receiving portion 19 to connect the two.

[0033] Figure 2 FIG. 2 shows an example of a main part of a mold structure of the circuit board 4 in the brushless fan motor of the present embodiment. Figure 2 It is from Figure 1 This is an enlarged view of the main part of the half-section view of the brushless fan motor viewed in a direction parallel to the central axis. Figure 2 The insulator 32 and the substrate storage portion 19 are arranged around the bearing support cylinder 17. The wall portion of the slot (the portion where the stator coil 3 is wound) of the insulator 32 on the bearing support cylinder 17 side extends in the axial direction of the rotating shaft 13. A cutout portion 35 composed of a recess or a groove is formed at the top end 34 of the wall portion. One end of the circuit substrate 4 on the bearing support cylinder 17 side is supported by the cutout portion 35 composed of the recess or the groove.

[0034] The insulator 32 supports one end of the bearing support cylinder 17 side of the circuit substrate 4 through a cutout portion 35 formed by a recess or a groove formed in the top end portion 34. A fixed thickness gap 39a is provided between the insulator 32 and the bearing support cylinder 17. An insulating material (a part of the molding) constituting the molded portion is sandwiched in the above-mentioned gap 39a. In addition, a fixed thickness gap 39b is also provided between the top end portion 34 of the insulator 32 at one end of the circuit substrate 4 and the substrate storage portion 19. An insulating material (a part of the molding) constituting the molded portion is also sandwiched in the gap 39b.

[0035] A jaw portion 36 is formed on the inner circumference of the bottom of the groove of the insulator 32 located on the side of the bearing support cylinder 17 (right-hand side in the figure), that is, the bottom of the groove of the insulator 32 in contact with the stator core 2, so as to surround the bearing support cylinder 17. In addition, a step 37 is formed on the outer circumference of the bearing support cylinder 17 opposite thereto so as to form a small diameter portion. That is, the small diameter portion is formed on the outer circumference of the bearing support cylinder 17 via the step 37. The jaw portion 36 abuts against the step 37 and fits with the small diameter portion. The jaw portion 36 abuts against the step 37 on the outer circumference of the bearing support cylinder 17, thereby suppressing the insulator 32 from moving in the direction opposite to the rotor assembly 6 along the rotating shaft 13. Therefore, not only the position of the insulator 32 but also the position of the entire stator assembly 1 formed integrally with the insulator 32 in the direction along the rotating shaft 13 is fixed.

[0036] The jaw 36 is formed so that the height of the jaw 36 relative to the inner peripheral surface of the insulator 32 is greater than the depth of the step 37 of the outer peripheral portion of the bearing support cylinder 17. A gap 39a is formed between the insulator 32 and the bearing support cylinder 17 to sandwich the insulating material (a part of the molded portion) constituting the molded portion.

[0037] In addition, the surface (abutment surface) where the jaw 36 of the insulator 32 and the step 37 of the bearing support cylinder 17 abut against each other is not limited to a specific surface. The abutment surface may be a surface located on a plane orthogonal to the axis of the rotating shaft 13, or may be a surface located on a plane or a curved surface that is not orthogonal to the coaxial line. Depending on the circumstances, the abutment surface may be a combination of the two surfaces, and may also have a concave and convex portion where the step 37 and the jaw 36 engage. In general, it is preferred that the jaw 36 and the step 37 abut against each other so as to play a positioning role as a positioning portion that inhibits the movement of the insulator 32 and the stator toward the substrate storage portion 19 side, or a cofferdam role as a cofferdam portion that inhibits the passage of liquid. The above-mentioned abutment structure may be any structure.

[0038] Thus, the circuit board 4 is provided between the heat insulating material constituting a part of the molded part. Therefore, even if moisture or oil enters from the outside, it is Figure 2 The water or oil flows along the arrows shown in the figure. Therefore, it is possible to suppress corrosion, erosion and other insulation failures of the circuit board 4 and reduce the durability of the circuit board 4 due to contact with water or oil.

[0039] In addition, the insulator 32 abuts against the step 37 of the outer peripheral portion of the bearing support cylinder 17 through the jaw 36. Therefore, even if water or oil enters to a considerable depth as shown by the arrow, the abutting portion of the jaw 36 and the step 37 constitutes a cofferdam 40, thereby suppressing the flow of water or oil along the arrow. In addition, based on the relationship between surface tension and the viscosity of water or oil, it is predicted that there are few cases where water or oil passes over the cofferdam and further reaches the stator core 2 side. In this regard, it is assumed that even if water or oil flows out further to a deeper depth beyond the cofferdam, the bearing support cylinder 17 formed of metal such as brass, the stator core 2 formed of steel plate, and the insulator 32 formed of resin are less likely to be affected by water or oil than the circuit substrate 4. Therefore, it is not easy to have an adverse effect on the main performance of the brushless fan motor.

[0040] As described above, the insulator 32 is configured such that the jaw portion 36 abuts against the step 37 of the outer peripheral portion of the bearing support cylinder portion 17. Thus, the insulator 32 has a positioning function of suppressing the movement of the stator assembly 1 formed integrally with the insulator 32. In addition, the insulator 32 has a cofferdam function of suppressing the passage of liquids such as water or oil entering from the outside. In addition, during implementation, it is of course possible to appropriately design in a manner that any one of the functions is dominant, depending on the use environment of the brushless fan.

[0041] Next, the molding step in the manufacturing process of the brushless fan motor will be described. Any manufacturing step that has been performed in the past can be adopted as the manufacturing steps other than the molding step.

[0042] The stator assembly 1, the circuit board 4 including the electronic components, and the plurality of lead wires 21 are integrally molded by a single injection of epoxy resin as an insulating material while being housed in the stator-side housing 14. Reference numeral 24 is a molded portion formed by this molding. In this example, the magnetic pole surface 2b of the stator magnetic pole of the stator core 2 is also thinly covered with epoxy resin as an insulating material.

[0043] Specifically, the molded portion 24 is formed by an epoxy resin having a hardness of Shore D30 to Shore D90 after curing. Although the epoxy resin having a hardness smaller than Shore D30 after curing has flexibility after curing, it has low reliability due to low heat resistance and adhesion after curing. In contrast, although the epoxy resin having a hardness greater than Shore D90 after curing has high heat resistance and adhesion after curing, it has the possibility of damaging the circuit substrate and electronic components due to low flexibility. However, in recent years, the durability of circuit substrates and electronic components to heat and stress has also been continuously improved. Therefore, even an epoxy resin having a hardness exceeding Shore D90 after curing can be used because of the above-mentioned advantages.

[0044] In the present embodiment, for example, ME-372 Shore D91 of Pelnox Co., Ltd. of Japan, XNR5002G Shore D90 of Nagase ChemteX Co., Ltd. of Japan, etc. can be used as resins for forming the molded portion 24. Molding resin agents mostly use epoxy resins. However, as long as it is a molding material that can exert the required performance by a thermosetting resin, any resin-based molding material can be used as a molding material for forming the molded portion 24. The molding material used can be, for example, a polyurethane resin system or a silicone resin system. In short, the molding material is not limited in the present embodiment. As long as it has the required performance such as durability against heat from circuit substrates and electronic components, hardness after curing, softness, heat resistance and adhesion, and contributes to the purpose of the present embodiment, any molding material can be used.

[0045] The mold for forming the molded portion is made so that the epoxy resin as an insulating material flows from the wire receiving groove 22 side of the connector 20 that receives the wire 21 to the stator side. As a result, the advantage of this structure is that the molding operation of the epoxy resin as an insulating material is done once, thereby reducing the working hours. In addition, there is no interface between the two molded portions in the molded portion 24 formed by the epoxy resin as the insulating material. Therefore, the waterproof effect can be improved. In addition, the pole surface 2b of the stator magnetic pole of the stator is also covered with the epoxy resin as an insulating material. Therefore, it is possible to suppress moisture from entering the interior of the stator core 2 from the pole surface 2b of the stator magnetic pole.

[0046] Furthermore, as described above, the molded material is interposed between the bearing support cylinder 17 and the insulator 32 and in the storage chamber 38 inside the substrate storage section 19. Therefore, the water or oil that enters from between the bearing support cylinder 17 and the substrate storage section 19 due to the capillary phenomenon is only sucked into the space between the molded portion 24 and the bearing support cylinder 17, and is unlikely to reach the circuit substrate 4. Furthermore, the water or oil that enters in the above manner is also substantially blocked by the contact between the jaw 36 of the insulator 32 and the step 37 of the outer peripheral portion of the bearing support cylinder 17. Therefore, the water or oil is unlikely to enter deeper.

[0047] Figure 3 A to C show examples of other molding steps in the manufacturing process of the brushless fan motor of the present embodiment. Matters not particularly described are the same as those in the first molding step example.

[0048] The bearing support cylinder 17 is formed by cutting from a metal such as brass. A step 37 having a shape larger than the diameter of the stator core 2 mounting portion is formed on the outer periphery of the bearing support cylinder 17 on the circuit board 4 side of the portion where the stator core 2 is mounted (see FIG. Figure 2The bearing support cylinder 17 is fixed to the stator side housing 14 (see FIG. 1 ) that holds and surrounds the entire brushless fan motor by insert molding at the end (top end) of the side where the connector 20 is provided. Figure 1 The stator-side housing 14 has a storage chamber 38 in its central portion. The storage chamber 38 has a certain depth around it so that the circuit board 4 mounted on the top end of the stator assembly 1 can be housed and molded.

[0049] In addition, a hollow portion for embedding in the bearing support cylinder 17 is formed in the stator including the stator core 2 made of laminated steel plates, etc., the insulator 32, and the stator coil 3. The wall portion of the insulator 32 on the side of the bearing support cylinder 17 extends in the axial direction of the rotating shaft 13. A cutout portion 35 made of a recess or a groove is formed at the top end 34 of the wall portion. One end of the circuit substrate 4 on the side of the bearing support cylinder 17 is supported in the cutout portion 35. A substantially circular stopper hole is provided in the circuit substrate 4 so that the circuit substrate 4 is embedded in the cutout portion 35 of the insulator 32 arranged in parallel in the circumferential direction. The circuit substrate 4 is temporarily fixed to the cutout portion 35 of the insulator 32 through the substantially circular stopper hole. In addition, a pin portion 5 is installed in the through hole 4a of the circuit substrate 4. The pin portion 5 is fixedly connected to the circuit substrate 4 by welding, thereby being electrically connected to the stator coil 3.

[0050] The circuit board 4 and the stator assembly 1 configured as described above are externally fitted in the bearing support cylinder 17 mounted on the stator side housing 14. During the external fitting, the jaw 36 of the insulator 32 is fitted until it contacts the step 37 of the outer peripheral portion of the bearing support cylinder 17. Thus, the circuit board 4 and the stator assembly 1 are positioned. The circuit board 4 is located at a predetermined position inside the storage chamber 38 of the substrate storage portion 19 of the stator side housing 14. Thus, the stator side assembly is completed after the preparatory stage of the molding process is completed.

[0051] exist Figure 3 In the state shown in A, the stator-side component that has completed the preparatory stage of the molding process is surrounded by a cup-shaped molding jig 41 that surrounds the portion to be molded.

[0052] In keeping Figure 3 In the state shown in A, Figure 3 As shown in FIG. 1B , the insulating material for molding is injected into the molding jig 41 from the injection hole, i.e., the gate (injection hole) 42, at the bottom of the cup-shaped molding jig 41. After the insulating material for molding is almost completely applied to the fine parts, it is heated or cooled for a certain period of time.

[0053] like Figure 3 As shown in FIG. 3C , after the insulating material is cured and hardened, the molding jig 41 is removed, and the molding of the stator-side component is completed.

[0054] The injection hole 42 of the insulating material of the cup-shaped fixture 41 is located at the bottom of the cup-shaped molding fixture 41. By injecting the insulating material for molding from the injection hole 42, the insulating material flows from the bottom side of the cup-shaped molding fixture 41 (the opposite side of the substrate storage portion 19) to the substrate storage portion 19 inside the molding fixture 41. At this time, the flow of the insulating material is mainly hindered by the stator core 2 and the like. As a result, when viewed in the axial direction of the rotating shaft 13, the stator assembly 1 is subjected to a force toward the substrate storage portion 19 side. However, in the stator assembly 1, the jaw 36 of the insulator 32 is abutted against the step 37 on the outer peripheral portion of the bearing support cylinder 17 to be positioned. Therefore, during the molding process, the possibility of positional displacement of the stator assembly 1 is small.

[0055] In addition, the location where the molding material is injected is not limited to the above-mentioned gate. For example, as described above, the molding material as an insulating material may be made to flow from the wire receiving groove 22 side of the connector 20 that receives the wire 21 to the stator side. In this way, any molding means may be used as long as the positioning function of the step 37 can be effectively utilized.

[0056] Thereafter, unnecessary mold excess portion 43 etc. is cut off. Thereafter, rotating shaft 13 of rotor assembly 6 is inserted and fixed so as to be axially supported in bearing support cylinder portion 17 via bearings 15 and 16. Thus, the main part of the brushless fan motor is completed.

[0057] In this embodiment, through the molding process of the brushless fan motor, the jaw 36 of the insulator 32 is in contact with the step 37 of the outer peripheral portion of the bearing support cylinder 17 to perform positioning. Therefore, during the molding process, the possibility of positional displacement of the stator assembly 1 is small. Therefore, the brushless fan motor can be easily manufactured and the manufacturing accuracy can be improved.

[0058] In addition, if a structure is adopted in which the molded portion covers the upper part of the magnetic pole surface 2b as in the above-mentioned embodiment, when the gap size between the rotor and the stator becomes smaller, even if the molding accuracy of the molding is improved, it is difficult to maintain the gap size within a specified range. Therefore, in this case, after forming the molded portion with epoxy resin as an insulating material in such a way that the magnetic pole surfaces 2b of multiple salient pole portions are exposed, a low-viscosity insulating resin (such as epoxy varnish) having a viscosity that can penetrate into the interior of the stator core can be applied to the magnetic pole surfaces of the multiple salient pole portions. As a result, the low-viscosity insulating resin enters between the multiple steel plates constituting the stator core 2 and exerts a waterproof effect. Therefore, by the above-mentioned method, the size of the gap between the magnetic pole surface of the stator and the rotor can be reduced. Therefore, it is possible to effectively prevent moisture or oil from entering or penetrating into the interior of the stator core.

[0059] This embodiment relates to a molding structure and a molding method thereof, which, in a brushless fan motor molded by an insulating material on the stator side, suppresses moisture or oil such as cutting oil from entering the control circuit substrate of the brushless fan motor and causing corrosion, erosion and other poor insulation.

Claims

1. A molded structure of a brushless fan motor, characterized in that include: A stator, comprising a core (2) formed by stacking a plurality of steel plates and having a plurality of salient pole portions (2a), the salient pole portions of which are wound with slot coils (3) via slots of an insulator (32) arranged around the core, and having a plurality of stator magnetic poles; A circuit substrate (4) fixed to the stator and having electronic components constituting a control circuit mounted thereon, wherein the control circuit is used to control current flowing in the coils constituting the plurality of stator magnetic poles; A rotor (6) having a plurality of rotor poles formed of permanent magnets on the inner circumference side and a plurality of blades on the outer circumference side; as well as The stator side housing (14) comprises: a bearing support cylinder (17) which accommodates bearings (15, 16) for rotatably supporting the rotating shaft of the rotor; a casing (18) surrounding the outer periphery of the blades of the rotor; a substrate storage portion (19) which covers the inner and outer peripheries of the circuit substrate except for the rotor side and the opposite side of the rotor to form a storage chamber for the circuit substrate; and a plurality of connectors (20) connecting the substrate storage portion and the casing. It also includes a molded portion (24), wherein at least the stator and the circuit substrate including the electronic components are molded by insulating material to form the molded portion (24). At least a portion of the circuit substrate is supported on a notch (35) at the top end of a protruding end formed on the substrate storage portion side and the rotation shaft side of the insulator. The substrate housing portion and the insulator are arranged to surround the bearing support cylinder portion. A part of the mold portion is interposed between the bearing support cylinder and the insulator and between the substrate storage portion and the insulator. The entirety of the circuit substrate located inside the storage chamber except for the portion of the protruding end formed on the substrate storage portion side of the insulator is covered by a portion of the mold portion.

2. The molded structure of the brushless fan motor according to claim 1, characterized in that: A small diameter portion is formed on the outer periphery of the bearing support cylinder by means of a step (37). A jaw portion (36) is formed on the inner circumference of the insulator and contacts the step and engages with the small diameter portion. The jaw portion is formed so that the height of the jaw portion relative to the inner peripheral side surface of the insulator is greater than the depth of the step. A part of the molded portion is interposed between the bearing supporting cylinder portion and the insulator.

3. The molded structure of the brushless fan motor according to claim 2, characterized in that: The surface where the step and the jaw portion abut against each other serves as a positioning portion that suppresses movement of the insulator and the stator toward the substrate housing portion or a dam portion that suppresses passage of liquid.

4. The molded structure of the brushless fan motor according to claim 3, characterized in that: The surface where the step and the jaw abut against each other includes a surface located on a plane orthogonal to the rotation axis.

5. The molded structure of the brushless fan motor according to claim 3, characterized in that: The surface where the step and the jaw abut against each other includes a surface located on a plane or a curved surface that is not orthogonal to the rotation axis.

6. The molded structure of the brushless fan motor according to claim 4 or 5, characterized in that: The surface where the step and the jaw portion abut against each other includes a concave-convex portion with which the step and the jaw portion engage.

7. The molded structure of a brushless fan motor according to any one of claims 1 to 5, characterized in that: The insulating material includes an epoxy resin having a predetermined hardness after curing.

8. The molded structure of a brushless fan motor according to any one of claims 1 to 5, characterized in that: The stator and the circuit board including the electronic components are molded by the insulating material in a state where the magnetic pole surfaces of the plurality of salient pole portions are exposed while being housed in the stator-side housing. The insulating material or another insulating material having a viscosity capable of permeating into the core is applied to the magnetic pole surfaces of the plurality of salient pole portions.

9. The molded structure of the brushless fan motor according to claim 8, characterized in that: The insulating material or the other insulating material applied to the magnetic pole surfaces of the plurality of salient pole portions includes a low-viscosity insulating resin.

10. A method for molding a brushless fan motor, the brushless fan motor comprising: A stator, comprising a core (2) formed by stacking a plurality of steel plates and having a plurality of salient pole portions (2a), the salient pole portions of which are wound with slot coils (3) via slots of an insulator (32) arranged around the core, and having a plurality of stator magnetic poles; A circuit substrate (4) fixed to the stator and having electronic components constituting a control circuit mounted thereon, wherein the control circuit is used to control current flowing in the coils constituting the plurality of stator magnetic poles; A rotor (6) having a plurality of rotor poles formed of permanent magnets on the inner circumference side and a plurality of blades on the outer circumference side; as well as The stator side housing (14) comprises: a bearing support cylinder (17) which accommodates bearings (15, 16) for rotatably supporting the rotating shaft of the rotor; a casing (18) surrounding the outer periphery of the blades of the rotor; a substrate storage portion (19) which covers the inner and outer peripheries of the circuit substrate except for the rotor side and the opposite side of the rotor to form a storage chamber for the circuit substrate; and a plurality of connectors (20) connecting the substrate storage portion and the casing. It also includes a molded portion (24), wherein at least the stator and the circuit substrate including the electronic components are molded by insulating material to form the molded portion (24). At least a portion of the circuit substrate is supported on a notch (35) at the top end of a protruding end formed on the substrate storage portion side and the rotation shaft side of the insulator. The substrate housing portion and the insulator are arranged to surround the bearing support cylinder portion. A part of the mold portion is interposed between the bearing support cylinder and the insulator and between the substrate storage portion and the insulator. The entirety of the circuit substrate located inside the storage chamber except for the portion of the protruding end formed on the substrate storage portion side of the insulator is covered by a portion of the mold portion. The molding method of the brushless fan motor is characterized by at least comprising: Preparing the insulator holding the circuit substrate and a stator assembly (1) including the stator; The stator assembly is fitted into a predetermined position of the bearing support cylinder in such a manner that the circuit substrate is located inside the substrate storage portion; Using a mold having a gate for injecting the insulating material for molding, enclosing the molded portion including at least the stator assembly; and The molded portion is formed by injecting the insulating material for molding from the gate of the mold.

11. The method for molding a brushless fan motor according to claim 10, characterized in that: The step of fitting the stator assembly into a predetermined position of the bearing support cylinder includes positioning the stator assembly by bringing a step of a small diameter portion formed on the outer periphery of the bearing support cylinder into contact with a jaw portion on the inner periphery of the insulator.

12. The method for molding a brushless fan motor according to claim 11, characterized in that: As the mold having the gate for injecting the insulating material for molding, the mold having the gate disposed on the side opposite to the substrate housing portion is used. The forming of the molding portion includes injecting the insulating material from the opposite side of the substrate receiving portion toward the substrate receiving portion along the axial direction of the rotating shaft.

13. The method for molding a brushless fan motor according to claim 12, characterized in that: The insulating material is injected so that a force pressing the stator assembly toward the housing chamber side is generated by the flow of the injected insulating material.

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