JPH09294345A - Fan motor and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form the rotor of a fan motor easily with good accuracy and obtain a low-cost and very reliable fan motor, by integrally forming the rotor of the fan motor with fins of an air blowing section when forming the fins by resin molding. SOLUTION: A fan motor is composed of a stator S around which a winding is wound, a rotor R which is rotatably installed and an air blowing section which is composed of a plurality of resin-molded fins 8a. The rotor Rhas a supporting member which allows the rotor R to rotate against the stator S and field magnets 7 located at a specified space from the stator S. In such a fan motor, the rotor R is integrally formed with the fins 8a when the fins are resin-molded. By this method, the thickness of a rotor case 6 can be made thin and thereby the weight of the rotor R can be reduced, resulting in the decrease in inertia. Therefore, electric characteristics of the fan motor can be enhanced and the durability of the motor can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fan motor used for information equipment, power equipment, etc. and a method for manufacturing the fan motor.

[0002]

2. Description of the Related Art The structure of a conventional fan motor is shown in FIGS.
It will be described based on. FIG. 5 is a diagram illustrating a method of attaching a shaft and a rotor case in a conventional fan motor, and FIG. 6 is a diagram illustrating a method of attaching a magnet and a blower to the rotor case in FIG.

First, in FIG. 5, reference numeral 31 denotes a shaft, which is press-fitted and fixed to a rotor case 33 via a bush 32. In order to further improve the attachment strength, a means such as caulking or bonding may be used. As shown in FIG. 6, the case assembly portion 40 completed in this way has a field magnet 34 mounted on the inner circumference of the rotor case 33 and a plurality of resin-molded fins on the outer circumference. The blower 35 is attached by press fitting or the like.

[0004]

However, in the above-described structure, the rotor of the fan motor is assembled in the steps of attaching the shaft 31 and the rotor case 33, attaching the magnet 34, and attaching the blower 35. Took a lot of steps. Moreover, shaft 3
1 and the rotor case 33 could not be firmly held unless the bush 32 was interposed between them, so that the workability was extremely poor, which also adversely affected the productivity.

In addition, when mounting each component as described above, it is necessary to strictly control the precision of these components, and the precision of the mounting jig is also important. Therefore, the finished product is generally expensive, and it is very difficult to reduce the cost.

Further, in the case where a large number of manufacturing processes are performed as described above, the influence of the dimensional variation of each component or the mounting variation becomes more remarkable in the subsequent processes, and the final finished rotor has an extremely high rotational balance. Was unstable. Therefore, noise and vibration are generated due to unbalanced rotation or backlash. In order to prevent these, it is possible to attach a weight for adjusting the rotation balance, but this method further deteriorates workability.

Therefore, the present invention solves the above-mentioned problems and provides a low-cost and highly reliable fan motor and a method of manufacturing the fan motor by accurately and accurately configuring the rotor of the fan motor. Especially.

[0008]

SUMMARY OF THE INVENTION The present invention focuses on resin molding of a blower section, and has a shaft, a rotor case, a field magnet, and a blower section as an integral structure. It is possible to significantly reduce the manufacturing process and obtain extremely stable rotatability without variations in mounting and play without strict control of the accuracy of each part.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION A fan motor according to the present invention comprises a stator having windings and a rotor rotatably arranged on the stator, and at least the rotor is rotatable with respect to the stator. A support member, and a field magnet arranged in the stator through a predetermined gap,
In a fan motor provided with a blower section including a plurality of resin-molded fins, the rotor is integrally formed at the same time when the fins are resin-molded.

It is preferable that the rotor has a rotor case having a receiving portion smaller than the inner diameter of the field magnet. In addition, it is effective that a rib integrally formed at the same time as the resin molding of the fin is arranged at the opening end of the field magnet.

The method of manufacturing a fan motor according to the present invention comprises a stator having windings and a rotor rotatably arranged on the stator, and at least the rotor is rotatable with respect to the stator. A method of manufacturing a fan motor, comprising: a supporting member to be fastened; a field magnet arranged in the stator through a predetermined gap; and a blower section including a plurality of fins resin-molded by a mold that can be combined. In the step of mounting the supporting member and the field magnet in one mold of the molding die, combining another mold with the one mold, and enclosing a synthetic resin in the combined molding die, A step of integrally molding the support member, the field magnet, and the fin,
It has.

It is preferable that the rotor includes a rotor case having a receiving portion smaller than the inner diameter of the field magnet, and has a step of integrating the rotor case and the field magnet.

[0013]

[Embodiment 1] FIG. 1 is a cross-sectional view of a main part of a fan motor according to an embodiment of the present invention. 2 shows a rotor of the fan motor shown in FIG. 1, where (a) is a sectional view thereof and (b) is a bottom view thereof. In the figure, reference numeral 1 denotes a shaft, and one end portion 1 a of the shaft 1
A groove a is discontinuously cut out on the circumference. Due to the presence of the groove a, the shaft 1 is firmly held by the resin molding described later. In addition to this, the same effect can be obtained by subjecting the one end 1a of the shaft 1 to knurling. The other end 1b of the shaft 1 is provided with a groove b.

A bearing holder 3 is arranged on the shaft 1 via a bearing 2, and a core 4 formed by laminating a plurality of thin plates such as silicon steel plates is fixed to the bearing holder 3. A winding 5 is applied to the core 4. In this way, the stator S is configured.

Reference numeral 6 denotes a rotor case. A field magnet 7 is attached to the inner circumference of the rotor case 6 so as to be spaced from the core 4 by a predetermined gap, and the shaft 1 is integrally formed by resin molding. And constitutes the rotor R of the fan motor. The rotor R is configured to be rotatable with respect to the stator S by a shaft 1 serving as a support member, and at the same time as the molding thereof, a blower unit 8 including a plurality of fins 8a is formed on the outer circumference of the rotor case 6. . Further, the rotor case 6 is formed with a receiving portion 6a smaller than the inner diameter of the field magnet 7,
When mounted on a molding die to be described later, it is concentric with the shaft 1 so that unbalanced rotation is not generated.

Reference numeral 9 is a circuit board. Various circuit components are mounted on the circuit board 9, and the ends of the windings 5 are connected to a circuit pattern formed on the circuit board 9. Further, 10 is a frame arranged so as to cover the outer periphery of the swirling space of the blower section, and 11 is a ring mounted in the groove b of the shaft 1 described above in order to prevent the rotor R from coming off.

As described above, since the rotor R is integrally formed at the time of resin molding of the blower section 8, the bush 32 as in the prior art is unnecessary. Further, in the conventional configuration, in order to firmly hold the shaft, the wall thickness of the rotor case 6 had to be increased. However, according to the present invention, the rotor case 6 is integrally formed by resin molding. Since the wall thickness can be reduced, the weight of the rotating portion R itself can be reduced, leading to a reduction in inertia (inertia).
Therefore, the electrical characteristics of the fan motor are improved and the durability is also greatly improved.

Further, as can be seen from FIG. 2, a plurality of ribs 12 are provided on the opening side of the field magnet 7. The ribs 12 are integrally formed at the same time as the resin molding of the blower unit 8, and are arranged at equal intervals on the end faces thereof.

With this arrangement, the field magnet 7
Not only can the ribs be prevented from falling off, but the ribs 12 can be used for adjusting the rotational balance. In this case, for example, the width of the ribs 12 can be changed by cutting or the like, or the balance can be easily adjusted by simply cutting the ribs 12 to remove them. In addition,
If the balance adjustment is not particularly required, the rib 12 may be formed in a circular shape along the end face.

Next, an example of a method of manufacturing the rotor R will be described with reference to FIG. In the figure, reference numeral 21 is an upper die of a molding die that is vertically separably combined, and 22 is a lower die of the molding die. This molding die is different from the conventional one in which only the blower part is resin-molded, and the lower die 22 is formed with a shaft positioning recess 22a for inserting and positioning the shaft 1, and further, the rotor case 6 is supported. Part 6
A rotor case positioning portion 22b corresponding to a is formed.

More specifically, first, the shaft 1 is mounted in the shaft positioning recess 22a of the lower mold 22 having the above-described structure. Further, the field magnet 7 is press-fitted into the inner circumference of the rotor case 6, and the rotor case 6 is attached to the positioning portion 22b in alignment with the positioning portion 22b. It should be noted that here, the mounting order and the like are not particularly questioned, and the magnet alone may be mounted on the lower mold 22, and then the rotor case 6 may be mounted on the lower mold 22.

After that, the upper die 21 is lowered so that the shaft 1, the rotor case 6 and the field magnet 7 are moved.
It is combined with the attached lower mold 22 of. Synthetic resin is enclosed in the combined molding die to integrally configure the shaft 1, the rotor case 6 and the field magnet 7, and simultaneously with this molding, a plurality of fins 8a are formed on the outer periphery of the rotor case 6. Let

With this configuration, the shaft 1, the rotor case 6 and the magnet 7 can be integrally formed during resin molding of the blower portion, and the number of manufacturing steps of the rotor R of the fan motor can be significantly reduced as compared with the conventional case. be able to. Further, the mounting precision of each component depends on the precision of the mold, and the receiving portion 6a of the rotor case 6 and the positioning portion 22b of the lower die 22 realize high-precision mounting without eccentricity with respect to the shaft 1. You can do it. Therefore, the rotor R becomes extremely stable, and it is possible to reduce vibration during rotation. In the experimental data, the conventional one was 0.21 [G],
In the present invention, the value is 0.034 [G], which is an improvement of 6 times or more.

[0024]

[Embodiment 2] FIG. 4 is a sectional view of a main part of a fan motor according to another embodiment of the present invention. In the above embodiment, the rotor R is supported by the shaft 1 and is rotatable with respect to the stator S, but in this embodiment, a bearing is used as the support member. That is, in the figure, a bearing 15 as a support member is integrally formed with the rotor R1 simultaneously with resin molding of the fin 8a. In this way, the rotor R1 is rotatably supported by the bearing 15 with respect to the fixed shaft 14. In this case, a recess for positioning the bearing 15 may be formed in the molding die.

The present invention is not limited to the above-mentioned embodiments, but various modifications can be made without departing from the gist of the present invention. For example, the molding dies may be combined in the vertical direction or may be combined in the horizontal direction, and the bearing may be a sintered oil-impregnated bearing or a ball bearing. Further, although the rotor case may become unnecessary due to the improvement of the field magnet, it goes without saying that even in such a case, the rotor case can be sufficiently applied.

[0026]

As described above, in the fan motor of the present invention, the rotor is integrally formed at the same time when the fins are resin-molded, so that the conventional bushing is unnecessary, and the fan motor is integrated by resin molding. By doing so, the wall thickness of the rotor case can be reduced, so that the weight of the rotating portion itself can be reduced, which leads to a reduction in inertia (inertia). Therefore, the electrical characteristics of the fan motor are improved and the durability is also greatly improved.

Further, by providing the rotor case with the receiving portion formed smaller than the inner diameter of the field magnet, the rotor can be easily positioned and integrated with the field magnet. Further, since ribs integrally formed at the same time as resin molding of the fins are arranged at the open ends of the field magnets, not only can the field magnets be prevented from falling off, but the ribs also contribute to rotation balance. Adjustment can be easily performed.

By adopting the fan motor manufacturing method of the present invention, it is possible to integrally configure the rotary drive unit including the shaft, the rotor case and the magnet during resin molding of the blower unit. It is possible to significantly reduce the manufacturing process of the rotating part. Also,
The mounting accuracy of each part will depend on the accuracy of the mold,
Highly accurate mounting can be realized.

Further, the rotor is provided with a rotor case having a receiving portion smaller than the inner diameter of the field magnet, and there is a step of integrating the rotor case and the field magnet, so that the receiving portion of the rotor case is included. In addition, the lower die positioning portion 22b enables highly accurate mounting without eccentricity with respect to the shaft 1. Therefore, the rotor R becomes extremely stable, and it is possible to reduce vibration during rotation.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a fan motor according to an embodiment of the present invention.

2A and 2B show a configuration of a rotor of the fan motor in FIG. 1, in which FIG. 2A is a sectional view of a main part thereof, and FIG.

FIG. 3 is a diagram showing a method of manufacturing a fan motor according to an embodiment of the present invention.

FIG. 4 is a sectional view of a main part of a fan motor according to another embodiment of the present invention.

FIG. 5 is a diagram illustrating a method of attaching a shaft and a rotor case in a conventional fan motor.

FIG. 6 is a diagram showing a method of attaching a magnet and a blower to the rotor case in FIG.

[Explanation of symbols]

 1, 31 ... Shaft 6, 33 ... Rotor case 7, 34 ... Field magnet 8, 35 ... Blower section R, R1 ... Rotor S ... Stator

Claims (5)

[Claims] 1. A stator having a winding, and a rotor rotatably arranged on the stator, wherein at least the rotor has a support member for allowing the rotor to rotate and a predetermined member for the stator. In a fan motor including a field magnet arranged through a gap and a blower section composed of a plurality of resin-molded fins, the rotor is integrally formed simultaneously with resin molding of the fins. Fan motor. 2. The fan motor according to claim 1, wherein the rotor has a rotor case having a receiving portion smaller than an inner diameter of the field magnet. 3. The fan motor according to claim 1, wherein a rib integrally formed at the same time as resin molding of the fin is arranged at an opening end of the field magnet. 4. A stator having a winding and a rotor rotatably arranged on the stator, wherein at least the rotor has a support member for rotating the stator, and a predetermined member for the stator. In a method of manufacturing a fan motor, comprising: a field magnet arranged through a gap; and a blower section composed of a plurality of fins resin-molded by a mold that can be combined, wherein The step of mounting the support member and the field magnet, the step of combining the one die with the other die, and encapsulating synthetic resin in the combined molding die, and the support member, the field magnet, and the A method of manufacturing a fan motor, comprising: a step of integrally forming a fin. 5. The rotor comprises a rotor case having a receiving portion smaller than the inner diameter of the field magnet,
The method of manufacturing a fan motor according to claim 4, further comprising a step of integrating the rotor case and the field magnet.