JP2022046122A - Fan motor - Google Patents

Abstract

To suppress the mixture of the grease of a grease seal and grease filled into a bearing, in a fan motor having the grease seal for preventing the intrusion of water and foreign matters from the outside.SOLUTION: A fan motor comprises a circuit baseboard and a stator, a bearing holder, a grease holding plate, sealing grease, and a seal material. The circuit baseboard and the stator are molded of synthetic resins. The bearing holder is formed into a cylindrical form, attached with a pair of bearings for rotatably supporting a rotating shaft which is connected to an impeller, and has an annular flange extending radially inward between the impeller and the bearing at the impeller side. The grease holding plate is formed into a cup form, and fit on the rotating shaft between the flange and the impeller at the inside of the bearing holder. The sealing grease is filled between the flange and the grease holding plate. The seal material seals an end part of the bearing holder at a side opposite to the impeller.SELECTED DRAWING: Figure 3

Description

The present invention relates to a fan motor.

A fan motor is a device that cools the inside by discharging heat generated inside a personal computer, an OA device, or the like to the outside by wind power generated by rotating a fan (blade).

A fan motor in which the internal stator and circuit board are sealed (molded) with synthetic resin has been proposed so that it can be used in places exposed to water or oil or in places with a lot of dust (see, for example, Patent Document 1). ..

In addition to the above-mentioned stator and circuit board, it is necessary to prevent water and foreign matter from entering the bearings that support the rotating shaft of the rotor. Therefore, an annular member that rotates with the rotor is provided at one open end of a tubular member called a bearing holder or a bearing support cylinder, and a cap is provided at the other open end. At one end, the labyrinth structure with a slight gap between the end and the annular member prevents the ingress of water and foreign matter.

However, the labyrinth structure with a small gap cannot completely prevent the intrusion of water and foreign matter, and for this reason, it is conceivable that a grease seal filled with grease between the oil seal and the bearing is used. (See, for example, Patent Document 2 and the like). In general, grease having performance suitable for each purpose is selected as the grease sealed in the bearing and the grease filled between the oil seal and the bearing.

Japanese Unexamined Patent Publication No. 2001-128408 Japanese Unexamined Patent Publication No. 2005-045968

However, since the grease filled between the oil seal and the bearing is in contact with the bearing, the heat generated by the high-speed rotation of the rotating shaft causes the grease sealed in the bearing to be between the oil seal and the bearing. There is a risk of mixing with the grease filled in. When the grease sealed in the bearing and the grease filled between the oil seal and the bearing are mixed, the grease sealed in the bearing may not maintain the specified performance, and the performance as a fan motor. May deteriorate.

The present invention has been made in view of the above, and in a fan motor provided with a grease seal for preventing the ingress of water or foreign matter from the outside, the grease of the grease seal and the grease sealed in the bearing are provided. It is an object of the present invention to provide a fan motor that suppresses mixing with and.

In order to solve the above-mentioned problems and achieve the object, the fan motor according to one aspect of the present invention includes a circuit board, a stator, a bearing holder, a grease holding plate, a grease for sealing, and a sealing material. .. The circuit board and the stator are molded with synthetic resin. The bearing holder has a tubular shape, and a pair of bearings that rotatably support the rotating shaft coupled to the impeller is mounted inside, and extends inward in diameter between the impeller and the bearing on the impeller side. Has an existing annular flange. The grease holding plate is cup-shaped and is fitted on the rotating shaft between the flange and the impeller inside the bearing holder. The sealing grease is filled between the flange and the grease holding plate. The sealing material seals the end of the bearing holder on the opposite side of the impeller.

The fan motor according to one aspect of the present invention is a fan motor provided with a grease seal for preventing the ingress of water or foreign matter from the outside, and the grease of the grease seal and the grease sealed in the bearing are mixed. It can be suppressed.

FIG. 1 is an external perspective view showing a configuration example of a fan motor according to an embodiment. FIG. 2 is a plan view of the fan motor of FIG. FIG. 3 is a sectional view taken along the line AA of the fan motor of FIG. FIG. 4 is a plan view showing a state in which a stator is mounted on a bearing holder insert-molded in a base portion integrally molded in a housing. FIG. 5 is a cross-sectional view showing a configuration example of Comparative Example # 1. FIG. 6 is a cross-sectional view showing a configuration example of Comparative Example # 2.

Hereinafter, the fan motor according to the embodiment will be described with reference to the drawings. The present invention is not limited to this embodiment. In addition, the relationship between the dimensions of each element in the drawing, the ratio of each element, etc. may differ from the reality. Even between the drawings, there may be parts where the relationship and ratio of the dimensions are different from each other. Further, in principle, the contents described in one embodiment or modification are similarly applied to other embodiments or modifications.

FIG. 1 is an external perspective view showing a configuration example of the fan motor 1 according to the embodiment. For convenience, the axial direction (rotational axis direction) of the fan motor 1 is the Z-axis direction, and the two orthogonal sides of the housing 11 in the longitudinal direction are the X-axis direction and the Y-axis direction, respectively. FIG. 2 is a plan view of the fan motor 1 of FIG. FIG. 3 is a sectional view taken along the line AA of the fan motor 1 of FIG. FIG. 4 is a plan view showing a state in which the stator 21 is mounted on the bearing holder 17 insert-molded in the base portion 12 integrally molded in the housing 11.

The fan motor 1 is a so-called axial fan, and air flows in the Z-axis direction (rotational axis direction). The fan motor 1 includes a housing 11, an impeller (hub 43, blades 44) arranged inside the housing 11, and a motor for rotating the impeller. The rotor of the motor is composed of a rotating shaft 32, a rotor yoke 41 and a magnet 42.

<About housing configuration>
The housing 11 is provided with a frame portion 11a constituting an outer frame, a hollow cylindrical wind tunnel portion 11b, and a substantially quadrangular flange 11c on both end faces in the axial direction of the wind tunnel portion 11b. Insertion holes 11d through which mounting screws and the like are inserted are provided at the four corners of the flange 11c. A base portion 12 and a plurality of spokes 13 (including a wide portion 14) are provided on one end side of the wind tunnel portion 11b in the axial direction, and a connector housing 15 is integrally formed on a part of the outer peripheral portion of the housing 11. It is formed. Inside the connector housing 15, a plurality of connector pins 16 are inserted and integrally molded with the connector housing 15 and arranged.

The base portion 12 has an annular portion 12a, a cylindrical outer peripheral wall 12b is formed on the outer peripheral edge of the annular portion 12a, and one end of the outer peripheral wall 12b in the axial direction is open. A hollow cylindrical bearing holder 17 made of a non-magnetic metal material such as brass is arranged in the center of the annular portion 12a, and a circuit board on which electronic components and the like are mounted inside the cylindrical outer peripheral wall 12b. 26 is arranged. The plurality of spokes 13 are arranged along the circumferential direction on the outer peripheral surface of the outer peripheral wall 12b, and are coupled between the outer peripheral surface of the outer peripheral wall 12b and the inner peripheral surface of the frame portion 11a of the housing 11.

With the bearing holder 17 inserted, the housing 11, the base portion 12, the spokes 13, and the connector housing 15 are integrally molded by injection molding of a thermoplastic resin.

<About the configuration of the stator>
The stator 21 is composed of a stator core 22, an insulator 23 mounted on the stator core 22, and a coil 25 wound around the stator core 22 via the insulator 23.

The stator core 22 is configured by laminating a plurality of thin plate-shaped core pieces in the axial direction, and the stator core 22 includes an annular core back and a plurality of teeth radially extending outward in diameter from the core back. There is. The core piece is made from a soft magnetic electromagnetic steel sheet or the like by means such as press working.

Insulators 23 made of an insulating synthetic resin material are mounted from both sides of the stator core 22 in the axial direction, and a coil 25 is wound around each tooth via the insulator 23. The terminal of the coil 25 is entwined and connected to a terminal pin arranged on one side in the axial direction of the insulator 23, and is solder-connected (bonded) to manufacture the stator 21.

The opening of the core back of the stator core 22 is fitted to the outer peripheral surface of the bearing holder 17. At this time, each of the terminal pins is inserted into a through hole formed in the annular portion 12a of the base portion 12 and a through hole formed in the wiring pattern of the circuit board 26, and each protrudes from the through hole of the circuit board 26. The tip of the terminal pin is soldered to the wiring pattern. By this connection, the terminal pin and the connector pin 16 are electrically connected via a wiring pattern.

The stator core 22 is fitted to the outer peripheral surface of the bearing holder 17, the terminal pin and the connector pin 16 are inserted into the through hole of the wiring pattern of the circuit board 26, and the solder-connected structure is set in the mold and the mold is formed. The mold is filled with, for example, a synthetic resin 51 made of epoxy resin, and the circuit board 26 and the stator 21 are molded.

<About the configuration of the rotor and impeller>
The rotor is composed of a cup-shaped rotor yoke 41 made of a soft magnetic material, a magnet 42 fixed to the inner peripheral surface of the rotor yoke 41, and a rotating shaft 32 made of a metal material coupled to the rotor yoke 41. A protrusion 41a is formed in the center of the cup-shaped rotor yoke 41 by burring, and the rotary shaft 32 is press-fitted and coupled to the protrusion 41a.

The rotor yoke 41 to which the rotating shaft 32 is connected is inserted, and the impeller is integrally molded by injection molding of a thermoplastic resin. The impeller is composed of a cup-shaped hub 43 formed on the outer periphery of the rotor yoke 41 and a plurality of blades 44 integrally formed on the outer peripheral surface of the hub 43. After the impeller is integrally formed, the annular magnet 42 is fixed to the inner peripheral surface of the rotor yoke 41 with an adhesive.

In the present embodiment, the rotor yoke 41 is inserted into the impeller and is integrally formed with the rotor yoke 41 by injection molding of resin. However, only the impeller is formed by injection molding of resin, and the impeller and the rotor yoke 41 are adhered to each other. It may be configured to be bonded with an agent.

<Bearing holder>
A step portion 17f is formed on the outer peripheral surface of a hollow cylindrical bearing holder 17 made of a non-magnetic metal material such as brass, and when the stator core 22 is fitted to the outer peripheral surface of the bearing holder 17, this step portion is formed. By abutting on 17f, the axial direction of the stator core 22 is positioned.

An annular flange 17e extending inward in diameter is integrally formed on the inner peripheral surface of the bearing holder 17, and a through hole through which the rotating shaft 32 is inserted is formed in the center of the flange 17e. A slight gap is formed between the rotating shaft 32 inserted through the through hole and the inner peripheral surface of the through hole.

A pair of bearings 31 are fitted inside the bearing holder 17, one bearing 31 abuts on the flange 17e, and a preload is applied between the bearing 31 and the other bearing 31 to apply a predetermined preload to the bearing 31. A spring 35 is interposed. The rotating shaft 32 is rotatably supported by a pair of bearings 31.

A grease holding plate 33 filled with sealing grease 34 is fitted on the inner peripheral surface of one end of the bearing holder 17, and on the inner peripheral surface of the other end of the bearing holder 17. A retaining ring 36 for restricting the movement of the other bearing 31 is attached.

<Grease holding plate and sealing grease>
The grease holding plate 33 fitted to the inner peripheral surface of one end of the bearing holder 17 has a cup-shaped shape, and penetrates through the center of the disk-shaped bottom plate for the rotating shaft 32 to be inserted. A hole is formed. The peripheral edge of the disk-shaped bottom plate is provided with a cylindrical side wall, and the side wall is fitted to the inner peripheral surface of the bearing holder 17. The grease holding plate 33 is used as a sealing material. For example, the grease holding plate 33 is made of nitrile (NBR) rubber. A slight gap is formed between the rotating shaft 32 inserted through the through hole of the bottom plate and the inner peripheral surface of the through hole.

The sealing grease 34 filled between the flange 17e formed on the bearing holder 17 and the grease holding plate 33 is sealed in the bearing 31 in order to prevent foreign matter from entering and moisture from entering. The characteristics are different from the grease, and the grease having improved water resistance is used, and the viscosity is higher than that of the grease sealed in the bearing 31. Therefore, even if a slight gap is formed between the rotating shaft 32 and the grease holding plate 33, the high-viscosity grease can prevent foreign matter and moisture from entering the inside of the bearing holder 17.

The viscosity of the sealing grease 34 is 30 at a shear rate of 20 / s and a temperature of 25 ° C. It is desirable that the viscosity after the second measurement is 1.0 Pa · s or more and 150 Pa · s or less. If it is smaller than 1.0 Pa · s, there is a concern that it will be difficult to maintain the sealing performance for a long period of time. Due to the influence of shear, it is removed (dissipated) from the gap of the grease holding plate 33, and there is a concern that the waterproof performance is deteriorated.

It is desirable that the sealing grease 34 has high water repellency, high heat resistance, and oil content does not easily evaporate. Further, the base oil of the sealing grease 34 is perfluoropolyether (PFPE), silicone oil, or fluorosilicone oil. One or more are used, and it is desirable that polytetrafluoroethylene (PTFE) is used as the thickener.

A name plate 52 is attached to the stepped portion on the opening side of the base portion 12. By attaching the name plate 52, foreign matter and moisture from the outside are prevented from entering the inside of the bearing holder 17. The name plate 52 functions as a sealing material.

In the present embodiment, the name plate 52 attached to the lower surface of the base portion 12 functions as a sealing material, but the "cap 26" as shown in FIG. 2 of Patent Document 1 is attached to the other end of the bearing holder 17. May be fitted.

<Comparison example>
FIG. 5 is a cross-sectional view showing a configuration example of Comparative Example # 1, and is a cross-sectional view (half omitted) of the waterproof brushless fan motor shown in Japanese Patent Application Laid-Open No. 2001-128408. In FIG. 5, a housing portion 18'that surrounds the outer periphery of a plurality of blades 12'of the rotor 6'is provided, and the rotating shaft 13'of the rotor 6'is a bearing 15 housed in a bearing supporting cylinder portion 17'. It is rotatably supported by', 16'. Then, in a state where the stator 1', the circuit board 4'including the electronic components, and the lead wire 21' are housed in the stator side case 14', they are molded using epoxy resin to form the mold portion 24'. The magnetic pole surface 2b'of the stator magnetic pole is also covered by the mold portion 24'.

Further, an annular member 25'is provided at one open end 17a'of the bearing support cylinder 17', and a slight amount is provided between the open end 17a'of the bearing support cylinder 17' and the annular member 25'. It constitutes a labyrinth structure that forms a gap. Further, a cap 26'is fitted as a sealing material to the other open end portion 17b'of the bearing support cylinder portion 17'. The labyrinth structure and the cap 26'prevent water containing oil mist from entering the bearings 15'and 16'in the bearing support cylinder 17'.

However, since a slight gap is formed between the open end portion 17a'of the bearing support cylinder portion 17'and the annular member 25', water passes through the slight gap to the bearing support cylinder portion 17. There is a risk that it will infiltrate the inside of the bearing, and there is a problem that the infiltration of water cannot be completely prevented.

Iron core 2', salient pole 2a', winding 3', through hole 4a', terminal pin 5', rotor side case 7', cup member 8', tubular part 8a', bottom wall part 8b', penetration Hole 8c', blade mounting hub 9', tubular part 9a', bottom wall part 9b', rotor magnetic pole 10', bush 11', board storage part 19', web 20', lead wire storage groove 22', The description of the communication passage 23'will be omitted.

FIG. 6 is a cross-sectional view showing a configuration example of Comparative Example # 2, and is a cross-sectional view of the geared motor shown in JP-A-2005-045968. In FIG. 6, the output shaft 26 "is pivotally supported via a bearing 25" fitted to one end of the case 21 ", and an oil seal is provided between the case inner wall of the case 21" and the output shaft 26 ". 31 "is sealed, and grease 42" is further filled between the oil seal 31 "and the bearing 25". Such a grease seal prevents foreign matter and water from entering from the outside. ing.

However, the grease 42 "filled between the oil seal 31" and the bearing 25 "is in contact with the bearing 25". When such a grease seal structure is applied to the fan motor of Comparative Example # 1, the grease and oil sealed in the bearing 25 "due to the heat generated by the high-speed rotation of the rotating shaft 13'(output shaft 26"). The grease 42 "filled between the seal 31" and the bearing 25 "may be mixed. The grease sealed in the bearing 25" is filled between the oil seal 31 "and the bearing 25". When mixed with the grease 42 ", the grease sealed in the bearing 25" may not maintain the predetermined performance.

<Effect of preventing foreign matter and water from entering the fan motor of the embodiment>
On the other hand, in the embodiments shown in FIGS. 1 to 4, since the circuit board 26 and the stator 21 are molded with the synthetic resin 51, it is possible to prevent foreign matter and water from entering them.

Further, even if moisture enters the inside of the stator 21 from the outside through the gap (air gap) formed between the magnet 42 and the stator core 22, the grease holding plate 33 and the sealing grease 34 make it waterproof. Is planned.

That is, since the bearing 31 and the sealing grease 34 are separated by the flange 17e formed on the inner peripheral surface of the bearing holder 17, the sealing grease 34 does not come into direct contact with the bearing 31. Therefore, it is possible to prevent the grease sealed in the bearing 31 from being mixed with the sealing grease 34 due to the heat generated by the high-speed rotation of the rotating shaft 32. As a result, the grease sealed in the bearing 31 does not deteriorate, and the performance of the fan motor 1 is not affected. Further, the grease holding plate 33 fitted to the inner peripheral surface of the bearing holder 17 prevents the sealing grease 34 from scattering, prevents the sealing grease 34 from running short, and prevents the surrounding contamination. can do.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

As described above, in the fan motor according to the embodiment, a circuit board and a stator molded with synthetic resin and a pair of bearings that rotatably support the rotating shaft coupled to the impeller are mounted inside, and the impeller and the impeller A tubular bearing holder with an annular flange extending inward between the bearing on the impeller side and a cup fitted on the axis of rotation between the flange and the impeller inside the bearing holder. It is provided with a grease holding plate having a shape, a sealing grease filled between the flange and the grease holding plate, and a sealing material for sealing the end opposite to the impeller of the bearing holder. As a result, in a fan motor provided with a grease seal for preventing water or foreign matter from entering from the outside, it is possible to prevent the grease of the grease seal from mixing with the grease sealed in the bearing. As a result, the grease sealed in the bearing does not deteriorate and does not affect the performance as a fan motor.

Further, the grease holding plate is formed of nitrile rubber. This makes it possible to enhance the sealing effect.

Further, the sealing grease has a higher viscosity than the grease sealed in the bearing, and is set within a predetermined range in which the viscosity is neither too low nor too high. As a result, the sealing performance can be maintained for a long period of time, no load is applied to the rotating shaft, and deterioration of the waterproof performance due to dissipation can be prevented.

Further, the sealing grease has high water repellency, high heat resistance, and properties that the oil content does not easily evaporate. As a result, the sealing performance can be maintained for a long period of time.

Further, as the sealing grease, one or more of perfluoropolyether, silicone oil, and fluorosilicone oil is used as the base oil, and polytetrafluoroethylene is used as the thickener. Thereby, the sealing grease having a desired property can be easily obtained.

The sealing material is a name plate or a cap. This makes it possible to easily seal the end portion of the bearing holder on the opposite side of the impeller.

Further, the present invention is not limited to the above embodiments. The present invention also includes a configuration in which the above-mentioned components are appropriately combined. Further, further effects and modifications can be easily derived by those skilled in the art. Therefore, the broader aspect of the present invention is not limited to the above-described embodiment, and various modifications can be made.

1 fan motor, 11 housing, 12 base part, 13 spokes, 14 wide part, 15 connector housing, 16 connector pins, 17 bearing holders, 21 stators, 22 stator cores, 23 insulators, 24 terminal pins, 25 coils, 26 circuit boards, 31 Bearing, 32 Rotating shaft, 33 Grease holding plate, 34 Sealing grease, 35 Preload spring, 36 Retaining ring, 41 Rotor yoke, 42 Magnet, 43 Hub, 44 Blades

Claims (6)

Circuit boards and stators molded with synthetic resin,
A pair of bearings that rotatably support the rotating shaft coupled to the impeller are mounted inside, and a tubular shape having an annular flange extending inward in the diameter between the impeller and the bearing on the impeller side. Bearing holder and
A cup-shaped grease holding plate fitted on the rotating shaft between the flange and the impeller inside the bearing holder.
Sealing grease filled between the flange and the grease holding plate, and
A sealing material that seals the end of the bearing holder on the opposite side of the impeller,
A fan motor equipped with. The grease holding plate is made of nitrile rubber.
The fan motor according to claim 1. The sealing grease has a viscosity of 1.0 Pa · s or more and 150 Pa · s or less when measured under the conditions of a shear rate of 20 / s and a temperature of 25 ° C.
The fan motor according to claim 1 or 2. The sealing grease has high water repellency, high heat resistance, and properties that prevent oil from evaporating.
The fan motor according to any one of claims 1 to 3. As the sealing grease, one or more of perfluoropolyether, silicone oil, and fluorosilicone oil is used as the base oil, and polytetrafluoroethylene is used as the thickener.
The fan motor according to any one of claims 1 to 4. The sealing material is a name plate or a cap.
The fan motor according to any one of claims 1 to 5.

Images