JP2011166857A - Insulator for motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulator for motors, capable of increasing a footprint of a circuit board without decreasing the footprint thereof, without incurring complication of a forming die, concerning a configuration in which the circuit board is fixed on the insulator. <P>SOLUTION: The insulator 14 includes: a cylindrical section 14a and arms 14b which radially extend outward from the cylindrical section and cover the teeth of a stator core. Engaging sections 14d having engaging hooks 14e are integrally formed on the cylindrical section 14a and cut sections 14f are formed at least on one side in the circumferential direction in the engaging sections 14d. Through-holes 14c are provided in positions where the arms 14b overlap with the engaging hooks 14e in the axial direction. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an insulator for a motor.

Conventionally, as an example of using a brushless DC motor for a rotation drive unit, there is an axial fan used as a cooling fan for OA equipment. The brushless DC motor is composed of a rotor and a stator, an impeller is fixed to the rotor, and the stator is composed of a stator core, an insulator, and a coil. A circuit board on which an electronic component such as a control component for causing an exciting current to flow through the coil and a Hall IC for detecting a change in magnetic pole accompanying rotation of the rotor is mounted and held on the insulator. When attaching a circuit board to an insulator, a configuration in which terminal pins implanted in the insulator are inserted into through holes in the circuit board and connected by soldering is generally used, but a circuit board holding portion is formed in the insulator, and the circuit board is formed. There is a configuration in which the circuit board holding portion is inserted into the insertion hole, the tip of the circuit board holding portion is engaged with the circuit board, and the circuit board is fixed to the insulator (for example, see Patent Document 1).

FIG. 6 is a diagram showing a cooling fan described in Patent Document 1. In FIG.
The motor 100 includes a stator portion and a rotor portion. The rotor portion includes a substantially cylindrical rotor magnet 121 and a rotor holder 122 having a cylindrical portion that holds the outer peripheral portion of the rotor magnet 121. The stator portion includes a coil 131. A wound stator core 132 and a circuit board 135 provided with lands 136 to which the wire ends of the coils 131 are electrically connected are provided. On the circuit board 135, electronic components such as a Hall IC that detects a change in magnetic pole accompanying rotation of the rotor magnet 121 and a drive IC that controls the excitation current to the coil 131 are mounted. An engagement claw 134 is formed in the insulator 133, and the circuit board 135 is held by the insulator 133 by the engagement claw 134 being inserted into and engaged with a hole formed in the circuit board 135.

The proximal-side insulator has a cylindrical portion and four arm portions. Among the four arm portions, three radial tip portions are formed with engaging claws 134 that protrude toward the proximal end side. Yes. These engagement claws 134 are inserted into the holes of the circuit board 135 and engaged, whereby the circuit board 135 is held by the insulator 133.

However, in the insulator 133 in the motor 100 of Patent Document 1, an engagement claw 134 for holding the circuit board 135 is formed at the distal end in the radial direction of the arm portion, and the engagement claw 134 is inserted into a hole formed in the circuit board 135. Since the circuit board 135 is held and fixed by inserting and engaging the circuit board 135, it is necessary to form a hole in the circuit board 135 for inserting the engagement claw 134 formed in the insulator 133. In addition, there is a problem that the mounting area of the electronic components on the circuit board 135 cannot be increased, and the degree of freedom in designing the wiring pattern is hindered by the holes for inserting the engaging claws 134.

On the other hand, there exists the structure of the insulator which formed the engaging claw around the ring frame provided with the circular opening (for example, refer patent document 2).
FIG. 7 is a view showing the insulator described in Patent Document 2, and FIG. 8 is a view showing a state in which the printed circuit board is held by the insulator shown in FIG.

The insulator 200 is composed of a first insulator 201 and a second insulator 202 for sandwiching the stator core from both sides in the axial direction, and a printed circuit board is held by the second insulator 202. The second insulator 202 includes a ring frame 203 having a circular opening 204, an arm portion 205, a column 206, and an engaging claw 207. The engaging claws 207 extend in the axial direction from around the circular opening 204 and are provided at four positions at equal intervals. The struts 206 extend in the same direction as the engaging claws 207 from the outer peripheral portion of the second insulator 202, and are provided at four positions at equal intervals. Then, as shown in FIG. 8, the stator core 208 is sandwiched and attached from both sides in the axial direction by the first insulator 201 and the second insulator 202, and the engaging claws 207 of the second insulator 202 are attached to the printed circuit board 210. The printed circuit board 210 is received by the post 206 of the second insulator 202 through four notches formed at equal intervals around the central opening.

JP 2009-148103 A Japanese Patent No. 3051959

However, in the second insulator 202 described in Patent Document 2, the engaging claws 207 formed around the ring frame 203 having a circular opening are arranged between the arm portions 205. Therefore, when applied to a configuration in which the number of arm portions 205 is increased while the motor diameter is constant, the engaging claws 207 and the arm portions 205 are overlapped in the axial direction, and the insulator 202 is molded by resin injection molding. In this case, it is difficult to manufacture the upper mold and the lower mold, and there is a problem that the molding mold for manufacturing the insulator is complicated and the cost is increased.

The present invention has been made in view of the above problems, and an object of the present invention is to reduce the mounting area of the circuit board without complicating the molding die in the configuration in which the circuit board is fixed to the insulator. An object of the present invention is to provide a motor insulator capable of increasing the mounting area.

In order to solve the above-mentioned problems, the present invention provides an insulator for a motor that covers a stator core provided with radially extending teeth, the motor insulator extending radially outward from the cylindrical portion and the stator core. The cylindrical portion that is provided with an arm portion that covers the teeth and overlaps with the arm portion in the axial direction is integrally formed with an engaging portion that includes an engaging claw, and at least one of the engaging portions in the circumferential direction. A notch portion is formed on the side of the arm portion, and a through hole is provided in the arm portion located at a position overlapping with the engaging claw in the axial direction.

According to the configuration of the present invention, it is possible to provide a motor insulator that can increase the mounting area without impairing the mounting area of the circuit board in the configuration in which the circuit board is fixed to the insulator.

It is a figure which shows the brushless DC motor equipped with the insulator of this invention, Comprising: It is sectional drawing of the axial flow fan using a brushless DC motor. It is a detailed view of the brushless DC motor location shown in FIG. It is the perspective view which showed the insulator of this invention. It is the top view seen from the side which mounts the circuit board in the insulator shown in FIG. It is sectional drawing in the DD location in FIG. It is a figure which shows the cooling fan equipped with the conventional insulator. It is a figure which shows another conventional insulator. It is a figure which shows the state which hold | maintained the printed circuit board in the insulator shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 is a view showing a brushless DC motor equipped with the insulator of the present invention, and is a sectional view of an axial fan using the brushless DC motor. FIG. 2 is an enlarged sectional view of the brushless DC motor shown in FIG. Is a perspective view showing an insulator of the present invention, FIG. 4 is a plan view of the insulator shown in FIG. 3, and FIG. 5 is a cross-sectional view taken along a line DD in FIG.

FIG. 1 is a view showing a brushless DC motor equipped with an insulator of the present invention, and is a cross-sectional view of an axial fan using the brushless DC motor. In the axial fan 1, reference numeral 2 denotes a casing whose outer shape is a rectangle (longitudinal) and whose section perpendicular to the rotation axis is a square. The casing 2 includes an upper casing 3 and a lower casing 4. A substantially circular ventilation hole is formed in the central portion of the upper casing 3, and an inner peripheral surface thereof forms a venturi portion. Are fitted inside the lower casing 4 to form an integral structure.
Note that the casing 2 is not limited to the shape of a split type or a quadrangular prism, and may of course be an integral type or a cylindrical shape.

  A storage portion 5 is held and fixed by a plurality of fixed blades 6 at the center of the lower casing 4. Accordingly, the fixed blade 6 is disposed on the outer peripheral surface of the storage portion 5 and is connected to the lower casing 4. The lower casing 4, the storage portion 5, and the fixed blade 6 are integrally formed by injection molding using a thermoplastic resin. Further, the fixed blades 6 are arranged at equal intervals in the circumferential direction on the outer peripheral surface of the storage portion 5, and both are appropriately curved. A fan motor 7 is disposed on the upper surface of the storage unit 5. The fan motor 7 is configured by a brushless DC motor, and includes a stayer 8 and an impeller 10 attached to the rotor 9.

The stator 8 includes a stacked stator core 11, an insulator 12 attached to the stator core 11, a coil 15 wound around the insulator 12, and a cylindrical bearing liner 16. A stator core 11 is fixed to the outer periphery of a cylindrical bearing liner 16, and two ball bearings 17 and 18 are held inside the bearing liner 16 at a predetermined interval.

An insulator 12 to be attached to the stator core 11 is an insulator made of resin, and includes an upper insulator 13 and a lower insulator 14. The insulator 12 is attached to both sides of the stator core 11 in the axial direction. Turned.

The impeller 10 includes a plurality of rotating blades 10b at equal intervals in the rotation direction on the outer periphery of an impeller body 10a having a cylindrical portion. The rotary blade 10b is an airfoil having a leading edge and a trailing edge, and has a unique curvature for receiving and guiding incoming air. The impeller 10 is integrally formed by injection molding with a thermoplastic resin. A bottomed cylindrical back yoke 21 is fitted and attached to the inner periphery of the cylindrical portion of the impeller body 10a. A hollow cylindrical rotor magnet 22 is mounted on the inner periphery of the back yoke 21. A boss portion 21a is provided at the center of the back yoke 21, and the other end of the shaft 20 is formed integrally with the back yoke 21 by the boss portion 21a. For this reason, the impeller 10 is configured such that the rotary blade 10b rotates around the shaft 20 as the shaft 20 rotates. A coil spring 24 for applying a preload to the ball bearing 17 is interposed between the boss portion 21 a and the inner ring of the ball bearing 17. A shaft 20 is inserted into the ball bearings 17 and 18 and is rotatably supported. An E-type retaining ring 19 is attached to one end of the shaft 20 via a shim 27 for adjusting dimensions, and the shaft 20 is prevented from being removed and positioned in the axial direction.

On the bottom surface side of the lower insulator 14, a circuit board 25 on which electronic components for supplying an exciting current to the Hall IC and the coil for detecting a change in the magnetic pole of the rotor magnet 22 are mounted. A means for attaching the circuit board 25 will be described.

FIG. 3 is a perspective view showing an insulator according to an embodiment of the present invention, and shows an example of the shape of the lower insulator 14. As shown in the figure, the lower insulator 14 includes a cylindrical portion 14a and nine arm portions 14b extending radially outward from the cylindrical portion 14a. The arm portions 14b cover the teeth 11a of the stator core 11. . After attaching the upper insulator 13 and the lower insulator 14 to the stator core 11, the coil 15 is wound around each arm part 14b.

A through hole 14c is formed on the inner peripheral side in the radial direction of the arm portion 14b of the lower insulator 14, and an engaging portion 14d having an engaging claw 14e at the tip of the cylindrical portion 14a in contact with the through hole 14c. Are integrally formed. The engaging portions 14d are formed at equal angular positions in the circumferential direction, and in this embodiment, three engaging portions 14d are formed. And the notch part 14f is formed in the both sides in the circumferential direction of each engaging part 14d.
In addition, although the notch part 14f is formed in the both sides in the circumferential direction of each engaging part 14d, it is not limited to this, If it is the structure by which the notch part 14f was formed in the one side in the circumferential direction at least Good.

As shown in the drawing, since the engaging claw 14e is formed at a position overlapping the arm portion 14b in the axial direction, when the lower insulator 14 is formed by resin injection molding, the upper mold and the lower mold are made of gold. Difficult to manufacture with molds. For this reason, the molding die for manufacturing the lower insulator 14 is complicated, and the cost is increased. In order to solve this problem, in the lower insulator 14 in the present embodiment, by forming a through hole 14c at a position overlapping the engaging claw 14e, a part of one mold of the upper mold and the lower mold is formed. A mold can be disposed at a position where the engaging claw 14e is inserted through the through hole. As a result, the engagement claw 14e can be formed using the upper and lower molds, and as a result, the mold can be easily manufactured without complicating the mold.
The basic structure of the upper insulator 13 is the same as that of the lower insulator 14, and is different only in that the upper insulator 13 is not formed with an engaging portion 14 d provided with an engaging claw 14 e.

The circuit board 25 has a disk shape, has an opening at the center thereof, and three protrusions 25a extending in the radial direction toward the center of the opening are formed at the periphery of the opening. Then, the engaging portion 14 d is inserted into the opening of the circuit board 25, and the three protruding portions 25 a of the circuit board 25 are positioned according to the notches 14 f of the lower insulator 14. Then, an elastic member 26 such as a disk-shaped rubber packing or an O-ring is interposed between the engaging claw 14 e and the circuit board 25 to hold the circuit board 25 on the bottom surface side of the lower insulator 14. . At this time, the projecting portion 25a of the circuit board 25 is placed on the surface of the cutout portion 14f of the lower insulator 14, whereby the position of the circuit board 25 in the axial direction is regulated and positioned at a predetermined position. By this positioning, the interval between the rotor magnet 22 and the Hall IC mounted on the circuit board 25 is set to a predetermined position.

As described above, the elastic member 26 is interposed between the engaging claw 14e and the circuit board 25 so that the circuit board 25 is held on the bottom surface side of the lower insulator 14. Even if there is some variation in the size of the joint portion 14d, the variation can be absorbed by the elastic member 26. As a result, the interval between the rotor magnet 22 and the Hall IC mounted on the circuit board 25 can be kept constant, so the rotor magnet 22 Can be detected stably. Further, the circuit board 25 can be securely held and fixed to the lower insulator 14.

Further, since the engaging portion 14d of the lower insulator 14 is inserted through the central opening of the circuit board 25, it is necessary to form a hole for engaging the engaging claw 14e on the mounting surface of the circuit board 25. There is no. For this reason, the mounting area of the circuit board 25 is not impaired, the mounting area can be increased, and the degree of freedom in designing the wiring pattern can be increased.

In the present embodiment, as described above, the configuration has been described in which the elastic member 26 is interposed between the engaging claw 14e and the circuit board 25 to hold the circuit board 25 on the bottom surface side of the lower insulator 14. However, it is needless to say that the present invention is not limited to this. For example, the elastic member 26 is placed on the stepped portion due to the radial difference between the insulating wall 14g formed on the cylindrical portion 14a of the lower insulator 14 and the cylindrical portion 14a, and the elastic member 26 and the engaging claw 14e are A configuration in which the circuit board 25 is interposed therebetween may be employed.

Further, the stepped portion is not limited to the above-described configuration, and may be any configuration as long as the elastic member 26 can be placed. For example, a part of the outer peripheral surface of the cylindrical portion 14a that bulges outward is provided. Needless to say, the upper surface of the bulging portion may be used as a stepped portion.

DESCRIPTION OF SYMBOLS 1 Axial fan 2 Casing 3 Upper casing 4 Lower casing 5 Storage part 6 Fixed blade 7 Fan motor 8 Armature 9 Rotor 10 Impeller 10a Impeller main body
10b Rotary blade 11 Stator core 11a Teeth 12 Insulator 13 Upper insulator 14 Lower insulator 14a Cylindrical part 14b Arm part 14c Through hole 14d Engaging part 14e Engaging claw 14f Notch part 14g Insulating wall 15 Coil
16 Bearing liner 17 Ball bearing 18 Ball bearing 19 E-type retaining ring 20 Shaft 21 Back yoke 21a Boss part 22 Rotor magnet 24 Coil spring 25 Circuit board 25a Protrusion part 26 Elastic member

Claims (5)

In an insulator for a motor that covers a stator core provided with radially extending teeth,
The motor insulator includes a cylindrical portion and an arm portion that extends radially outward from the cylindrical portion and covers the teeth of the stator core, and engages with the cylindrical portion that is located at a position overlapping the arm portion in the axial direction. An engaging portion having a claw is integrally formed, a notch portion is formed at least on one side in the circumferential direction of the engaging portion, and the arm portion located at a position overlapping with the engaging claw in the axial direction A motor insulator comprising a through hole. 2. The motor insulator according to claim 1, wherein a plurality of the engaging portions are arranged at equal angular positions in the circumferential direction. The motor insulator according to claim 1, wherein a notch is formed on both sides of the engaging portion. The insulating wall is provided on the upper surface of the cylindrical portion, and the insulating wall is formed with a smaller diameter than the cylindrical portion, thereby forming a step. Insulator for motor. 5. The motor insulator according to claim 1, wherein a part of an outer peripheral surface of the cylindrical portion is formed to bulge in a radial direction. 6.