JPH07213038A - Small motor - Google Patents

Abstract

PURPOSE:To provide a small-sized motor by omitting a bearing and bearing the shaft with an insertion hole provided at a case and an insertion hole provided at the center of a bracket. CONSTITUTION:A permanent magnet 5 is fixed to the inside periphery of a cylindrical case 4 which has an insertion hole 42 for a motor shaft 1 provided at the center of a bottom face 41 at one end and an opening 43 at the end. A rotor 2 being constituted by the setting a rotor vane where a coil is wound around a motor shaft 1, is attached inside this permanent magnet 5. One end of the motor shaft 1 is inserted and born in the through hole 42 made at one end face of a case 4, and also the other end of the motor shaft 1 is inserted and born in the insertion hole 91 made at the center of the bracket 9 fixed in the opening made at the other end of the case 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized motor, and more particularly to a small-diameter and small-sized micromotor suitable for use in small-sized electric equipment.

[0002]

2. Description of the Related Art The above-mentioned small motor is used as a vibration signal generation source by being housed in various kinds of card-shaped small electric equipment such as a wrist watch or a pager, or as a driving source of a micromachine. It is something. For example, as a pager, recently, a structure in which an incoming call is transmitted by vibration instead of electronic sound is widely used, and a small motor having a diameter or a thickness that can be accommodated in the housing is used as a vibration generation source. The structure adopts a structure in which a rotating body eccentrically attached to a drive shaft of a motor converts a rotational force into vibration to generate vibration. In addition, a small electric device of this type usually uses a battery as a power source, and thus a DC motor such as a brush motor is widely used as the small motor.

[0003]

By the way, in recent years, along with the miniaturization of various devices, the miniaturized motors housed in these devices are required to be further miniaturized. However, it is difficult to further reduce the size of this type of small motor, and conventionally, there is a problem that a diameter of about 5 mm is the limit of downsizing (reduction in diameter).

Therefore, the present invention has been made to solve the above problems, and an object thereof is to provide a smaller motor having a smaller diameter and a smaller diameter.

[0005]

In order to solve the above-mentioned problems, in order to solve the above-mentioned problems, according to the structure of the present invention, which has the above-mentioned object, the motor shaft 1 is provided at the center of the bottom surface portion 41.
A permanent magnet cylinder 5 is fixed to the inner circumference of a cylindrical case 4 having an insertion hole 42 at the other end and an opening 43 at the other end, and a coil is wound around the outer circumference of the motor shaft 1 inside the permanent magnet cylinder 5. The rotor 2 having the rotor blades fitted thereto is attached, one end of the motor shaft 1 is inserted into and supported by the insertion hole 42 formed in the one end surface of the case 4, and the other end of the motor shaft 1 is attached. The technical means is provided by inserting and supporting the insertion hole 91 formed in the central portion of the bracket 9 fixed to the opening formed on the other end side of the case 4.

A technical means in which a coating layer 22 formed by plastic deposition is applied to the outer periphery of the other end of the motor shaft 1, and the commutator pieces 3, 3, 3 are directly placed and fixed on the coating layer 22. Was taken.

Further, the motor shaft 1 is provided at the center of the bottom portion 41 at one end.
The cylindrical case 4 having the insertion hole 42 and the opening 43 at the other end is skew-attached to the inner peripheral surface of the cylindrical case 4 in which a bonding material made of synthetic resin is mixed with rare earth magnetic particles and molded into a cylinder. A magnetized permanent magnet cylinder 5 is fixed, a coating layer is formed on the entire inner and outer surfaces of the case 4 having the above-mentioned permanent magnet cylinder 5 by plastic deposition, and inside the permanent magnet cylinder 5,
A predetermined number of rotor blades 21 obtained by punching and molding permalloy thin plates are stacked and fitted on the motor shaft 1, and an insulating coating layer 22 is applied to the outer surfaces of the motor shaft 1 and the rotor blades 21 by plastic deposition. The rotor 2 in which the coil 6 is wound is attached to the rotor blades 21 group, the insulating coating layer 22 on the other end side of the motor shaft 1 is applied, and the commutator pieces 3, 3, 3 are directly attached. Mount and fix the above motor shaft 1
One end of the motor shaft 1 is inserted into and supported by the insertion hole 42, and the other end of the motor shaft 1 is inserted into an insertion hole 91 provided in the center of a bracket 9 molded of an oil-containing synthetic resin fixed to the opening 43. It is a technical measure that is supported by the company.

[0008]

Therefore, in the small motor of the present invention, the permanent magnet cylinder 5 is fixed to the inner circumference of the case 4, the rotor 2 is mounted inside the permanent magnet cylinder 5, and one end of the motor shaft 1 is attached to one end surface of the case 4. Since the other end of the motor shaft 1 is inserted into and supported by the insertion hole 91 of the bracket 9 on the other end side of the case 4, the motor shaft 1 is smaller than the conventional one.・ Has the effect of reducing the diameter.

Further, since the insulating coating layer 22 is applied to the outer periphery of the motor shaft 1 and the rotor blade plate 21 group, the motor shaft 1 and the case 4 or the commutator pieces 3, 3, 3 can be insulated as required. It is a thing.

Furthermore, since a coating layer is formed on the entire inside and outside of the case 4 having the permanent magnet cylinder 5 by plastic deposition, the permanent magnet cylinder 5 made of rare earth magnetic particles, which is likely to rust, has an anticorrosive effect. The coating layer is also applied to the inner peripheral surface of the insertion hole 42 on one end surface of the case 4, and the insertion hole 42 acts as a smooth bearing.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a small motor of the embodiment,
This small motor is mounted in a small electric device and is driven to rotate by being supplied with DC electric power. The motor shaft 1, the rotor 2 attached to the motor shaft 1, and the rotor 2 are encapsulated in the motor shaft. 1 is configured to include a substantially cylindrical case 4 and a permanent magnet cylinder 5 provided on the inner surface of the case 4.

The motor shaft 1 is a thin shaft made of a metal rod. In the embodiment, a small-diameter shaft made of a 0.4 mm iron rod or a stainless steel rod is used, and this is heat-treated appropriately to secure the required strength.

The rotor 2 is not clear from the figure,
A coil 6 is wound around a metallic rotor blade plate 21 in which crescent-shaped electrode portions are continuously provided at the tips of blade bodies protruding in three directions. As the rotor blade 21, a predetermined number of magnetic punched magnetic plates such as Permalloy having a thickness of 0.2 mm are stacked. By making the rotor blade 21 from a thin magnetic plate in this manner, eddy current is small and loss can be reduced. Further, by using permalloy for the magnetic plate, it is possible to obtain a structure having less residual magnetism and less iron loss. In this embodiment, the rotor 2 has a diameter of 1.
It is 8 mm.

A predetermined number of rotor blades 21 are fitted and attached to the motor shaft 1 to form a rotor body, and the outer surface of the motor body 1 of the rotor body and the rotor blade plate group 21 is made of plastic. The insulating coating layer 22 is applied by vapor deposition.
In general, the bearing support portion of the motor shaft 1 is different from the bearing material in principle, and if an insulating coating layer 22 is also applied to this portion by plastic vapor deposition, as will be described later in this embodiment. Since the bearing material is a synthetic resin, the same kind of synthetic resin is used as the sliding surface, so that both ends of the motor shaft 1 are masked 104.10 as shown in FIG.
Insulation treatment in the state of 5 and specifically, the motor shaft 1
An insulating coating layer 22 (thickness: 10 to 50 μm) may be formed on the outer surface of the motor shaft 1 and the rotor blades 21 by leaving the both end portions of the. Although plastic deposition was actually performed on the entire surface without masking 104.105, no difference was observed in durability and performance.

Further, the motor shaft 1 is provided with a commutator constituted by combining three commutator pieces 3, 3, 3 on the outer surface of the insulating coating layer 22.

The commutator 3 is generally constructed by disposing the commutator piece 3 on the outer surface of an insulative commutator cylinder 103 (see FIG. 9) fixed to the motor shaft 1. The commutator cylinder 103 is omitted in the small motor. That is, in the small motor of the embodiment, the commutator pieces 3, 3, 3 are directly attached to the outer surface of the insulating coating layer 22 formed on the motor shaft 1.

For mounting the commutator pieces 3, 3, 3 on the motor shaft 1, various conventionally known methods can be used as long as they can be fixed to the motor shaft 1. In the small-sized motor of the embodiment, as shown in the figure, a predetermined number of commutator pieces 3, 3, 3 whose main portion is a curved surface along the motor shaft 1 and whose one end is bent at a right angle as a terminal piece portion. (3 in the illustrated example) along the outer surface side of the insulating layer, and by fitting the fastening ring 7 on the outside of the commutator pieces 3, 3, 3.
These commutator pieces 3, 3, 3 are fixed to the motor shaft 1.

The commutator cylinder 30 is omitted because the commutator cylinder 30 is conventionally made of a synthetic resin molded product, so that the motor shaft 1 having an outer diameter of about 1 mm and a diameter of 0.4 mm is provided at the center thereof. This is because it is difficult to manufacture a synthetic resin molded product having a hole through which it is inserted. Furthermore, if the commutator pieces 3, 3, 3 have a large diameter, the storage space for the brush 10 described later is reduced, and the brush 10 Since the elasticity cannot be used effectively, the brush 1
This is because the force of the pressure contact between 0 and the commutator pieces 3, 3, 3 becomes large, and a large torque loss occurs. Therefore, if the commutator cylinder 30 is omitted, the structure is simplified and manufacturing is facilitated, and the outer diameters of the commutator pieces 3, 3, 3 are reduced, and the torque loss can be reduced.

The coil 6 connected to the commutator pieces 3, 3, 3 is a thin conductor wire, and in the present embodiment, 0.04 mm to 0.04 mm.
A conductor wire of about 45 mm is used. Further, the connection between the coil 6 and the commutator pieces 3, 3, 3 is performed by attaching heated solder to the portion A of the coil 6 as shown in "Fig. 4" and by the heat of the solder as shown in "Fig. 5". After the insulating coating 6a on the surface of the coil 6 is melted to expose the conductive portion 6b inside, the end portions of the commutator pieces 3, 3, 3 are placed on the portion A where the conductive portion is exposed,
A method of gluing with a conductive adhesive is used. In the figure, the portion A is the middle portion of the coil 6, but it may be the end portion of the coil 6. Further, as the conductive adhesive, a known one mixed with a conductive powder such as silver can be used. Further, the insulating coating of the coil 6 may be melted with a solvent instead of melting with the solder.

As described above, the coil 6 and the commutator pieces 3, 3, 3
The reason why the connection with the adhesive is gluing is that if the conductor is thin and the connecting component is small to this extent, soldering becomes difficult due to cutting of the conductor with a small diameter, heat transfer to the component, etc. This is because the gluing allows easy and reliable connection.

The permanent magnet cylinder 5 is formed by skew magnetizing a cylindrical magnet obtained by mixing a rare earth magnetic material particle such as neodymium with a bonding material made of synthetic resin.

Usually, a ferrite magnet is used for the permanent magnet cylinder 5 used in a small motor. However, if the ferrite magnet has a small capacity, a sufficient magnetic force cannot be obtained and the physical strength is weak. If it is made thin, there is a high risk of damage. On the other hand, by using a material obtained by kneading the magnetic particles and the bonding material such as a synthetic resin material into a cylindrical shape as described above, the magnetic force and the strength can be kept high even if the thickness is reduced, and the damage can be prevented. There is less risk.

As shown in FIG. 8, the permanent magnet cylinder 5 is skew-magnetized so that the boundary lines 51, 51 between the S pole and the N pole have a constant twist angle with the central axis. Is
The reason for the smooth rotation of the motor is to surely start the rotation even if the motor has a relatively large rotational torque resistance at the start of the rotation of the motor.

The permanent magnet cylinder 5 may be formed by an injection molding method or another known method such as blow molding. Further, when dimensional accuracy is particularly required, a large-sized and thick-walled product finished by lathing to a desired dimensional accuracy may be used. Incidentally, in the small motor of the embodiment, the permanent magnet cylinder 5 having a wall thickness of 0.2 mm is used, and the case 4 is made of a magnetic metal material having a wall thickness of 0.2 mm. Was set to 3 mm.

Further, the case 4 has the insertion hole 42 of the motor shaft 1 at the center of the bottom surface 41 at one end and the opening 43 at the other end, which is the same as in the conventional case, but normally it is shown in FIG. As shown. The bearing metal 102 is housed in the right end portion of the case 4, and the right side portion of the motor shaft 1 is the bearing metal 102.
Was supported by. On the other hand, in this embodiment, this type of bearing body 102 is not used. That is, after the permanent magnet cylinder 5 is attached to the inner circumference of the case 4 (after the state shown in FIG. 2 is obtained), a coating layer (FIG. 2) is formed on the entire inside and outside of the case including the inner circumference of the permanent magnet cylinder 5 by plastic deposition. Is not applied), and then the motor shaft 1 is inserted into the insertion hole 42 formed in the right end surface of the case 4, and the one end bottom surface portion 41 (the insertion hole 42)
The right end portion of the motor shaft 1 is supported by using the bearing as a bearing.

Since the insertion hole 42 is opened by machining, its inner peripheral surface is usually rough. Therefore,
Although it cannot be used as it is for a bearing, it becomes a smooth surface when a coating layer is applied by plastic deposition, and the friction resistance can be set small by selecting the material of the coating layer, and it can be used for a bearing.

An eccentric weight, which is a rotating body for generating vibration, is fixed to the tip portion of the motor shaft 1 protruding from the case 4.

Normally, the bracket 9 attached to the opening of the case 4 is provided on the left side of the case 4 shown in FIG.
Also, the bearing metal 101 was attached.
On the other hand, in this embodiment, this type of bearing body 101 is not used, and the bracket 9 fixed to the case opening 43 by fitting or the like is made of a material having a small sliding resistance, such as an oil-containing Delrin-based synthetic resin. It is made of oil-impregnated synthetic resin, and the insertion hole 91 provided in the center of the bracket 9 is also used as a bearing.
The left end of the motor shaft 1 supported by the bracket 9 is projected outward of the case 4.

The bracket 9 is positioned on the left end surface of the case 4 in the figure, and the end surface claws 92, 92 (see FIG. 2) of the case 4 are folded back and locked. It is a thing. The left end of the motor shaft 1 is
Insertion hole 91 formed at the inner end (center portion) of the bracket 9
And is pivotally supported, and is prevented from moving left and right in FIG.

Brushes 10, 10 can be attached to the bracket 9. As shown in FIG. 6, one end of each of the brushes 10 and 10 is pressed against the commutator pieces 3, 3 and 3 by its spring pressure, and the other end is extended outward of the bracket 9 (front side in FIG. 6). And is used as a lead wire connection terminal. As this type of brush 10, 10, a press contact portion with the commutator pieces 3, 3, 3 is a fork-shaped contact piece 10a (fork brush), although not necessarily clear from the drawings. .

As shown in FIG. 7, the contact piece 10a is provided with a clad material 10b formed by rolling and laminating noble metal such as iridium on the contact surface side with the commutator pieces 3, 3, 3 to conduct electricity. It improves the sex.

The small-sized motor of the embodiment constructed as described above can be constructed with a small size and a small diameter of about 3 mm.

[0034]

Since the present invention is as described above, it is possible to provide a small motor having a smaller size and a smaller diameter than the conventional one.

In particular, the present invention relates to conventional bearings 101, 10
Since 2 is omitted and the insertion hole 42 provided in the case 4 and the insertion hole 91 provided in the center of the bracket 9 are used for supporting, it is possible to provide a smaller type motor having a smaller diameter than the conventional one. is there.

Further, according to the present invention, the permanent magnet cylinder 5 is skew-magnetized by mixing the earth magnetic particles with the bonding material made of the synthetic resin and molding it into a cylindrical shape. It is possible to provide a small motor having sufficient magnetic force and physical strength and capable of being manufactured with a small diameter.

Further, since the commutator pieces 3, 3, 3 are directly placed and fixed on the other end side of the motor shaft 1 on which the coating layer is applied, the outer diameters of the commutator pieces 3, 3, 3 are fixed. It is possible to provide a small-sized motor that can be formed to be small and can effectively utilize the spring property of the brush 10.

Further, according to the present invention, since the coating layer is formed on the entire inner and outer surfaces of the case 4 having the permanent magnet cylinder 5 by the plastic deposition, the inner peripheral surface of the insertion hole 42 is covered with this coating layer, and the smooth bearing is formed. It is possible to provide a small-sized motor having a small diameter.

Further, an insulating coating layer 22 is applied to the outer surfaces of the motor shaft 1 and the rotor blades 21 group by plastic deposition, leaving both ends of the motor shaft 1, and the rotor blades 21 group is coiled. The rotor 2 wound with 6 is attached, and the insulating coating layer 2 on the other end side of the motor shaft 1 is attached.
Since the commutator pieces 3, 3 and 3 are directly mounted on and fixed to the element 2 which has been subjected to 2, the required insulation between the motor shaft 1 and the case 4 or the commutator pieces 3, 3 and 3 can be achieved, and the commutator is also provided. The outer diameter of the pieces 3, 3, 3 can be set to be small, and a small-diameter small motor with small rotational torque resistance can be provided.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a vertical sectional view of a case portion.

FIG. 3 is a front view of the rotor during insulation treatment.

FIG. 4 is an explanatory diagram of an example of a method of connecting a commutator piece to a coil in an example.

FIG. 5 is an explanatory diagram of an example of a method of connecting a commutator piece to a coil in an example.

FIG. 6 is a front view of a brush that constitutes an embodiment.

FIG. 7 is a cross-sectional view of a contact piece of a brush that constitutes an embodiment.

FIG. 8 is a perspective view of a permanent magnet.

FIG. 9 is a vertical sectional view of a conventional example.

[Explanation of symbols]

 1 Motor Shaft 2 Rotor 3 Commutator Piece 4 Case 5 Permanent Magnet Tube 6 Coil 7 Fastening Ring 9 Bracket 10 Brush

Claims (3)

[Claims] 1. A cylindrical case (4) having a through hole (42) for the motor shaft (1) at the center of the bottom surface (41) at one end and an opening (43) at the other end, which is permanently attached to the inner circumference of the cylindrical case (4). Magnet tube (5)
A rotor blade (2) in which a coil (6) is wound around the outer periphery of the motor shaft (1) inside the permanent magnet cylinder (5).
1, 21, 21 ...) are attached, and one end of the motor shaft (1) is inserted into an insertion hole (42) formed in one end surface of the case (4). And the other end of the motor shaft (1) is inserted into an insertion hole (91) formed in the center of a bracket (9) fixed to an opening (43) formed on the other end of the case (4). A small motor supported by. 2. A coating layer (22) formed by plastic vapor deposition is applied to the outer periphery of the other end of the motor shaft (1), and the commutator element (3, 3) is applied on the coating layer (22).
The small motor according to claim 1, wherein the third and third parts are directly mounted and fixed. 3. An inner peripheral surface of a cylindrical case (4) having an insertion hole (42) for a motor shaft (1) at the center of a bottom surface portion (41) at one end and an opening portion (43) at the other end. A case (4) having the above-mentioned permanent magnet tube (5) is obtained by fixing a rare-earth magnetic material particle into which a bonding material made of a synthetic resin is mixed and molded into a cylindrical shape to which a skew-magnetized permanent magnet tube (5) is fixed. ) Is coated with a coating layer on the entire inner and outer surfaces by plastic deposition, and a predetermined number of rotor blades (21) obtained by punching and molding permalloy thin plates on the motor shaft (1) are fitted inside the permanent magnet cylinder (5). Then, an insulating coating layer (22) is applied to the outer surfaces of the motor shaft (1) and the rotor blades (21) group by plastic deposition, and the rotor blades (2)
1) A rotor (2) around which a coil (6) is wound is attached to the group, an insulating coating layer (22) on the other end side of the motor shaft (1) is applied, and then a commutator piece (3, 3). , 3) are directly mounted and fixed, one end of the motor shaft (1) is inserted into and supported by the insertion hole (42), and the other end of the motor shaft (1) is inserted into the opening (43). A small motor which is inserted into and supported by an insertion hole (91) formed in the center of a bracket (9) molded of oil-impregnated synthetic resin to be fixed.