JPH09135547A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor which can be manufactured with the improved production efficiency and the reduced cost and which can be assembled easily with the high precision while its stator can be fitted to the motor case without producing crackings and breakage even if the size of the motor is small. SOLUTION: A field stator 2 composed of a permanent magnet is fitted in the interior of a cylindrical motor case 1 to compose a motor. The stator 2 is composed of a layer-built sheet 20 which is made from a sheet-type stator substrate 21 which consists of a bonded magnet made of magnetic particles which are bonded to each other by using heat-resistant soft synthetic resin as binder and on which a film layer made of soft synthetic resin is integrally formed. The stator 2 is wound into a cylindrical shape with the film layer 22 outside and, in that state, housed in the cylindrical motor case 1 and the stator 2 is contacted tightly to the inner circumference of the motor case 1 and fixed by the elastic repulsion force of the wound stator 2 itself.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small motor mainly used for precision equipment and the like.

[0002]

2. Description of the Related Art A permanent magnet field DC motor is well known as a small motor used in precision equipment and the like. This motor is a cylinder made of a permanent magnet along an inner peripheral surface of a cylindrical motor case. The field-shaped stator is attached, and the rotor is provided inside the stator.

Conventionally, as a field stator made of a permanent magnet, a cylindrical sintered magnet processed product obtained by sintering a magnetic material, a cylindrical plastic magnet molded product obtained by injection molding, and the like are often used. Has been.

[0004]

However, when manufacturing a stator composed of a sintered magnet processed product, cutting, cutting,
It is necessary to manufacture the product through a number of steps such as drilling, which causes a problem of lowering production efficiency and increasing cost. Moreover, as the product becomes smaller, handling in each of the above steps becomes inconvenient, so the diameter is several mm especially for precision equipment.
In the case of manufacturing a stator as an ultra-small motor product, there is a problem that production efficiency is further lowered and cost is further increased.

Further, when a stator made of a sintered magnet processed product or a plastic magnet molded product is mounted on a motor case, it is fixed to the case with an adhesive or the like. It is a troublesome work, and it must be done carefully while absorbing the assembly error to the case.Especially in the case of small motor products, a lot of work is required for the operator, and the motor assembly work is very complicated. There was a problem.

<Background of the Invention> By the way, the inventor of the present invention has proposed that in the field stator material of the small motor as described above,
Attention is paid to what is made of a bonded magnet such as a rubber magnet sheet in which magnetic powder is bound with a soft synthetic resin as a binder.

That is, if this rubber magnet sheet is housed in the motor case in a wound state and is closely fixed to the inner peripheral surface of the motor case by the expansion force due to its elastic repulsion, the rubber magnet sheet (stator ) Is elastically deformed to fit inside the case and the assembly error is absorbed, and the troublesome adhesion work to the case is unnecessary, so that the motor assembling work can be greatly improved.

However, the bonded magnet needs to contain a large amount of magnetic powder in order to obtain good magnetic properties.
It is very brittle and strain cracks are likely to occur. On the other hand, the microminiature motor as described above is a very small one with a diameter of about 8 mm. To accommodate the rubber magnet sheet as a stator in the case of this small diameter motor, the rubber magnet sheet can be up to about 6 mm in diameter. It is necessary to wind to a small diameter. At the time of this winding, the rubber magnet sheet was cracked from the outer peripheral surface side and was broken, so that it could not be mounted on the case and could not be commercialized.

The present invention has been made in view of the above circumstances. It is possible to improve the production efficiency and reduce the cost, and moreover, to wind the stator into a small diameter without causing cracks or breaks. It is an object of the present invention to provide a motor which can be assembled in a small-diameter motor case with high accuracy and easily, and which can be suitably used particularly as a small motor product.

[0010]

As a result of earnest research, the present inventor has developed a motor capable of achieving the above object by mounting a stator having a specific configuration in a motor case in a specific configuration. We have found what we can offer.

That is, according to the present invention, in a motor in which a field stator made of a permanent magnet is provided inside a cylindrical motor case, the stator is bound with magnetic powder using a heat resistant soft synthetic resin as a binder. A sheet-like stator substrate made of bonded magnets is provided on one side with a laminated plate in which a coating layer made of a soft synthetic resin is integrated, and the stator is wound in a cylindrical shape with the coating layer facing outside. The gist of the invention is that the stator is accommodated in the motor case in a closed state, and the stator is closely fixed to the inner peripheral surface of the motor case by elastic repulsive force.

In the motor according to the present invention, the stator can be mounted on the case only by winding the stator and housing it in the motor case. That is, at the time of this assembly, since the stator accurately fits in the case due to elastic deformation, there is no assembly error, and the elastic repulsive force makes it adhere to the case. It becomes unnecessary.

In addition, since the outer surface of the stator has a coating layer made of soft synthetic resin, excellent bending resistance can be obtained, and cracks are surely prevented even when wound into a small diameter. Even if the motor case has a small diameter, it can be installed without any trouble.

The stator according to the present invention can be easily and efficiently manufactured by utilizing a rolling roll or thermoforming such as extrusion molding.

[0015]

1 is a sectional view schematically showing a permanent magnet field DC motor according to an embodiment of the present invention.
As shown in the figure, this motor is arranged inside a cylindrical motor case (1), a cylindrical stator (2) arranged in the case (1), and a stator (2). A rotor (3).

As shown in FIGS. 1 to 3, the stator (2) has a sheet-shaped stator base end (21) made of a bonded magnet such as a rubber magnet and a coating layer (22) laminated on one side thereof. It is composed of an integrated laminated body (20).

This laminated body (20) is cut into a predetermined size as shown in FIG. 4 to form a stator (2), and the stator (2) is wound into a cylindrical shape. With the
As shown in FIG. 1, it is housed in a cylindrical motor case (1). At this time, the stator (2) is closely fixed to the inner peripheral surface of the motor case (1) by the expansion force based on the elastic repulsion.

Here, in the stator (2) of the present invention, the stator substrate (21) needs to be composed of a bond magnet to which magnetic powder is bound using a heat resistant soft synthetic resin as a binder. As the bond magnet, any one can be used as long as it is a so-called rubber magnet having a soft synthetic resin such as vulcanized rubber or a thermoplastic resin as a binder and has heat resistance. Specific examples thereof include polyamide-based elastomers such as nylon 6, nylon 12 and their copolymers, as well as those using thermoplastic polyetherester elastomers, polyurethane-based resins, etc. as binders. Above all,
Considering heat resistance and flexibility, it is preferable to use a polyamide elastomer as a binder.

As the magnetic powder mixed in the binder resin, known magnetic powders such as ferrite magnet powder and rare earth magnet powder can be used. Among them, neodymium-iron-boron (Nd-Fe-B) intermetallic compounds can be used. Can be preferably used.

The mixing amount of the magnetic powder in the stator substrate (21) is 85 to 95% by weight, preferably the lower limit value is 89.
It is preferable that the upper limit is set to not less than 93% by weight and not more than 93% by weight. That is, if the amount of this mixture is too large, good flexibility cannot be obtained and it becomes brittle, and there is a risk of cracking and breaking when the stator (2) is mounted on the motor case (1). , Not preferable. On the contrary, if the mixing amount of the magnetic powder is too small, good porcelain characteristics may not be obtained, which is not preferable.

The stator substrate (21) has a wall thickness of 0.5 when applied to a micro motor having a diameter of about 8 mm.
.About.2.0 mm, preferably a lower limit value of 0.8 mm or more and an upper limit value of 1.2 mm or less is used.
That is, if the wall thickness is too thin, a crack may occur when the stator (2) is mounted on the motor case (1), which is not preferable. On the other hand, if the wall thickness is too large, good flexibility cannot be obtained, which is not preferable.

In addition to the binder resin and the magnetic powder, well-known additives such as coupling agents may be appropriately mixed in the stator substrate (21).

As a method of molding the stator substrate (21),
Suitable examples include a rolling roll method such as calendering and an extrusion molding method.

As the coating layer (22) provided on one surface of the stator substrate (21), it is necessary to use one made of a soft synthetic resin. Specifically, polyurethane-based resin,
Polyamide-based resins and the like can be exemplified as suitable ones, and of these, it is preferable to use a polyurethane-based resin.

The film thickness of the coating layer (22) is 25 to 75.
μm, preferably the lower limit is 35 μm or more and the upper limit is 65 μm.
μm or less, and more preferably, the lower limit value is 45 μm or more,
The upper limit value is preferably 55 μm or less. That is, if this film thickness is too thin, the stator substrate (21) cannot be sufficiently protected, and when the stator (2) is mounted on the motor case (1), there is a risk that cracks may occur and break. , Not preferable. On the contrary, if the coating layer (22) is too thick,
It is not possible to obtain sufficient flexibility as the stator (2),
It is not preferable because the mounting on the motor case (1) becomes difficult.

The coating layer (22) may contain the above-mentioned magnetic powder to the extent that the function as a coating is not impaired.

As a means for laminating and integrating the coating layer (22) on the stator substrate (21), the stator substrate is formed by extrusion while the extruded coating layer is integrated on one surface thereof. A two-layer extrusion method (extrusion coating method),
Immediately after extrusion of the stator substrate (21), a film laminating method (bonding method) in which a film or sheet for a coating layer is integrated on the substrate (21)
In addition, a coating method for coating the coating material for the coating layer on the stator substrate (21) may be mentioned as a suitable example.

As described above, according to this motor, since the stator (2) is constituted by the laminated body (20) in which the coating layer (22) is integrated on one surface of the rubber magnet sheet, the stator is fixed. When the child (2) is wound into a cylindrical shape and accommodated in the motor case (1), the stator (2) is closely fixed to the inner peripheral surface of the motor case (1) by the expansion force based on the elastic repulsion. It At the time of this assembly, since the stator (2) is accurately fitted to the case (1) by elastic deformation, no assembly error or the like occurs, and furthermore, the elastic repulsion force makes the case (1) closely adhere to the case (1). Since the troublesome work of using the adhesive is unnecessary, the motor assembling work can be performed accurately and easily.

Moreover, since the stator (2) has the coating layer (22) made of a soft synthetic resin on the outer surface side thereof, excellent bending resistance can be obtained, and cracks or cracks can be generated even when wound into a small diameter. It is possible to reliably prevent the occurrence of cracks, and even if the case (1) has a small diameter, it can be attached to the case (1) without any trouble. Therefore, the motor according to the present embodiment can be suitably used especially as a micro motor product for precision equipment.

Further, since the stator (2) can be easily manufactured by utilizing thermoforming such as extrusion molding, the production efficiency can be improved and the cost can be reduced.

[0031]

EXAMPLES Examples related to the present invention and comparative examples for deriving the effects thereof will be described below.

[0032]

[Table 1] In carrying out the examples and the like, the stator substrates (A) and (B) shown in Table 1 above were prepared. That is, "PebaX 353
3 (trade name, manufactured by Toray Industries, Inc.) "and" Pebax 403 "
3 (trade name, manufactured by Toray Industries, Inc.) "in a ratio of 3: 1 and 9% by weight of a polyamide elastomer (binder) and an intermetallic compound of neodymium-iron-boron (Nd-Fe-B). A composition mixed with 91% by weight of magnetic powder was extruded to obtain a relatively soft stator substrate (A) having a thickness of 1 mm (heat resistance of 80 ° C.).

Further, a polyamide elastomer (binder) in which "Pevax 3533 (trade name, manufactured by Toray Co., Ltd.)" and "Pebax 4033 (trade name, manufactured by Toray Co., Ltd.)" are blended in a ratio of 1: 1 is used. Then, in the same manner as above, extrusion molding was performed to obtain a stator substrate (B) (heat resistance of 100 ° C.), which was slightly stiffer than the substrate (A) and had a thickness of 1 mm.

Example 1 A soft polyurethane resin (two-component type) was applied to one surface of the stator substrate (A) to form a coating layer having a thickness of 50 μm, and a laminate (stator) was obtained. It was

The outer diameter of the stator is 16 mm, 14 mm, 12 mm, 1 with the coating layer outside.
Cylinders were rounded to 0 mm, 8 mm, and 6 mm, and the state of cracking at that time was observed. Those that did not crack at all were marked with "○", and those with a slight crack on the outer peripheral surface were marked with " “Fair” and the one in which cracking occurred was evaluated as “x”. The evaluation results are shown in Table 2 below.

[0036]

[Table 2] <Example 2> A coating layer was formed on one surface of the stator substrate (B) in the same manner as above to obtain a laminate (stator), and the same evaluation was performed. The evaluation results are also shown in Table 2 above.

<Comparative Examples 1 and 2> The above stator substrate (A)
Using (B) as a stator as it was, the same evaluation as above was performed. The evaluation results are also shown in Table 2 above.

As is clear from Table 2 above, in Examples 1 and 2 related to the present invention, cracks hardly occur in bending, and the bending performance is excellent. It turns out that it is suitable for. In particular, the stator of Example 1 using a relatively soft stator substrate has a size of 6 mm.
It can be seen that even when bent to the outer diameter, cracking does not occur, and it has excellent bending performance.

On the other hand, in Comparative Examples 1 and 2 which deviate from the gist of the present invention, cracks easily occur upon bending, and even Comparative Example 1 made of a relatively soft material is bent to an outer diameter of 8 mm. Then, cracking occurs, and in Comparative Example 2 made of a hard material, even if it is bent to an outer diameter of 16 mm,
It can be seen that cracking occurs and the bending performance is poor, making it unsuitable for the stator of a small motor.

[0040]

As described above, according to the motor of the present invention, the stator has the laminated plate in which the coating layer made of the soft synthetic resin is integrated on one surface of the stator substrate made of the rubber magnet sheet. The stator is housed in the motor case in a wound state with the coating layer on the outer side, and is fixed tightly to the inner peripheral surface of the motor case by the elastic repulsive force. That is, when the motor is assembled, the stator is exactly wound into the case, and the stator accurately fits in the case due to elastic deformation, so that there are no assembly errors and the elastic repulsion force. Since it comes into close contact with the case, there is no need for a bonding work, and the assembly can be performed easily with high accuracy. Moreover, since the stator has a coating layer made of a soft synthetic resin on the outer surface side, it is possible to obtain excellent bending resistance, and it is possible to reliably prevent cracking even when wound into a small diameter, Even if the motor case has a small diameter, it can be installed without any trouble. Therefore, the present invention can be suitably used especially as a small motor product. In addition, the stator uses a rolling roll, thermoforming such as extrusion molding,
Since the manufacturing can be performed easily and efficiently, there is an effect that the production efficiency can be improved and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing a motor according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a laminated body used as a material for a stator in the motor of the embodiment.

FIG. 3 is a cross-sectional view showing a stator laminate of the embodiment.

FIG. 4 is a perspective view showing a stator of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Motor case 2 ... Stator 20 ... Laminated plate 21 ... Stator substrate 22 ... Coating layer

Claims (1)

[Claims] 1. A motor in which a field magnet stator made of a permanent magnet is provided inside a cylindrical motor case, wherein the stator is a bond magnet in which magnetic powder is bonded using a heat resistant soft synthetic resin as a binder. On one surface of a sheet-shaped stator substrate consisting of a laminated plate in which a coating layer made of soft synthetic resin is integrated, the stator is wound in a cylindrical shape with the coating layer facing outward. A motor which is housed in the motor case and whose stator is closely fixed to the inner peripheral surface of the motor case by elastic repulsive force.