JP2000152585A - Flat coreless oscillatory motor employing holding torque - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate starting by arranging at least one air core coil on one side of an eccentric rotor, forming the air core coil at least partially of a magnetic plating wire and holding the eccentric rotor at a specified position during stoppage through magnetism of the magnetic plating wire and the magnetic force of a magnet. SOLUTION: An eccentric rotor 1 comprises two air core armature coils 2, 3 shifted to one side and molded integrally of high density high sliding resin 4. The air core armature coil 2 employs a winding of magnetic plating wire wherein the inner through hole diameter of the coil is increased and the winding is reduced in order to avoid excess magnetic attraction. A magnet 5 is a doughnut type disc where four poles of N and S are magnetized equally and alternately and the width of the magnet 5 is substantially equal to the inner through hole diameter of the air core armature coil 2. When the eccentric rotor 1 is stopped, center of the air core armature coil 2 is held at an intermediate position between the N and S poles of the magnet 5 by reluctance torque.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat coreless vibration motor suitable as a silent information source for small mobile communication devices (pagers, portable telephones) and a vibration source for massagers.

[0002]

2. Description of the Related Art Conventionally, a flat coreless vibration motor is disclosed in Japanese Patent Application Laid-Open No. 63-290153 and Japanese Utility Model Application No. 63-111.
No. 868. As shown in FIGS. 10A and 10B, all of these components are provided with an eccentric rotor 27 in a housing 26 including a case 24 and a bracket 25.
The eccentric rotor 27 includes a rotor holder 28, a shaft 29
The structure is such that the rotating shaft 31 is rotatably supported by the oil-impregnated bearings 29 and 30 respectively disposed on the case 24 and the bracket 25 through the.

[0003]

A plurality of the above,
For example, an arrangement in which three armature coils are unevenly distributed on one side is popular in the market because the amount of movement of the center of gravity can be large, but is disadvantageous in terms of cost because there are three coils. . In addition, this 3-coil type is actually
As disclosed in Japanese Patent No. 33573, it is very short for all the coils to contribute to the torque during one rotation, and the two coils are always energized in view of the principle of rotation. Further, the two-coil type disclosed in Japanese Patent Application Laid-Open No. 63-290153 has a problem that the center of gravity is less moved because the coil sides at both ends exceed 180 °.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to hold a magnetic flux from a magnet effectively by reluctance torque and to increase the amount of vibration by increasing the amount of movement of the center of gravity, thereby increasing the amount of vibration and the number of coils and magnets. It is an object of the present invention to provide a flat coreless vibration motor with a reduced cost by reducing the effective cross-sectional area.

[0005]

Means for Solving the Problems To solve the above problems, an eccentric rotor having at least one air-core coil arranged on one side and a commutator attached thereto, and this eccentric rotor are provided. A pair of brushes for supplying power to the air-core coil, at least a part of the air-core coil is formed of a magnetic plated wire, and the eccentric rotor is formed by utilizing the magnetism of the magnetic plated wire and the magnet force facing the magnet. This can be achieved by holding a specific position at the time of stoppage and configuring a means for preventing the segments adjacent to the slit of the commutator from short-circuiting with the brush. Specifically, the means for preventing the segments adjacent to the slit of the commutator from being short-circuited by the brush as described in claim 2 is a projection disposed in the slit, and at least one of the two sides of the projection. Should be recessed. Further, as described in claim 3, the air-core coil may be composed of two coils, one of which may be formed of a magnetic plated wire. Further, it is preferable that the width (difference between the outer diameter and the inner diameter) of the magnet substantially coincides with the inner diameter of the coil.

According to the first aspect of the invention, the eccentric rotor is held at a specific position when stopped by the magnetic plating wire, so that the eccentric rotor can be easily started. According to the second aspect, it is possible to prevent the adjacent segments from being short-circuited by the brush at the slit portion. According to the third aspect, the sliding powder such as resin is stored in the concave portion, thereby preventing a problem that the sliding powder appears on the segment surface. According to the fourth aspect, the hold by the reluctance torque can be reliably used, and the magnet becomes small, which is advantageous in cost.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a plan view of a main part showing a positional relationship between an eccentric rotor and a magnet showing a first embodiment of a flat coreless vibration motor using a holding torque according to the present invention, and FIG. 2 is a first embodiment of a flat coreless vibration motor. FIG. 3 is a cross-sectional view taken along line AA of FIG. 2 and a rear view for explaining the commutator. FIG. 4 is an enlarged sectional view of an essential part for explaining a flat plate commutator and a brush which are main members of the motor, and FIG. 5 is an enlarged view for explaining a cylindrical commutator and a brush according to a second embodiment of the present invention. 6, 7 and 8 are explanatory views of the principle of rotation of the motor, FIG. 9 is a plan view of a main part showing a third embodiment of the present invention, and FIG. 10 is a conventional flat vibration. It is sectional drawing which shows a motor.

In FIG. 1 to FIG. 5, an eccentric rotor 1 is formed integrally with a high-density and high-slidability resin 4 by biasing two air-core armature coils 2 and 3 to one side. (FIG. 1) Here, as one of the two air-core armature coils, an air-core armature coil 2 formed by winding a magnetic plating wire of extremely thin plating is used. The air-core armature coil 2 formed by winding such a magnetic plated wire has a relatively large winding shaft (increases the diameter of a through hole in the coil) in order to avoid a large magnetic attraction force, and has a smaller number of turns than the others. I have. The magnet 5 facing such an eccentric rotor 1 is in the shape of a donut-shaped disk, and is magnetized alternately with N and S equally in four poles.
The width of the magnet 5 substantially matches the width of the through-hole in the coil of the air-core armature coil 2, and the outer peripheral position of the magnet 5 matches the outer peripheral position of the through-hole in the coil of the air-core armature coil 2. The inner peripheral position of the magnet 5 is arranged so as to coincide with the outer peripheral position of the through-hole in the coil of the air-core armature coil 2. That is, the through-hole in the coil of the air-core armature coil 2 is arranged so as to overlap the outer circumference and the inner diameter of the magnet 5. Therefore, the eccentric rotor 1 is rotated four times every 90 ° during one rotation by the reluctance torque of the magnetically plated air-core armature coil 2 as shown in FIG.
The center of the air-core armature coil 2 is
At an intermediate position between the N pole and the S pole.

At the center of the magnet-side surface of the eccentric rotor 1, a four-pole flat commutator 6 is provided concentrically as shown in FIG. The flat-type commutator 6 will be described below with reference to FIG. 3. FIG. 3 is a rear view as viewed from the AA section in FIG. The plate-type commutator 6 forms each of the segments 6a, 6b, 6c and 6d in a printed wiring pattern with a central angle of approximately 90 degrees,
It is precious metal plated. 7 is sliding contact angle 9
A pair of precious metal thin plates or precious metal plated brushes set at 0 °. Reference numeral 8 denotes a slit between the segments to prevent a short circuit caused by the brush 7.
It is relatively wide, about 7 mm.

In the middle of the slit 8, a rectangular through-hole 8a is formed, which becomes a path for the high-density and high-slidability resin 4 during molding. The high-density and high-sliding resin 4 is provided with the rectangular through holes 8.
a through the recess 8b on both sides as shown in FIG.
The protrusion 8c is integrally provided with the high-density and high-slidability resin 4. Therefore, there is no risk that the adjacent segments (for example, 6a and 6d) of the noble metal thin plate brush 7 straddle the slit 8 and short-circuit.
Because there is no large step at the slit 8 portion, the eccentric rotor 1 can obtain smooth rotation,
Specific position using reluctance torque, that is,
Since the vehicle stops at the position shown in FIG. 1 (the same applies to the other three positions during one rotation), the next start can be easily performed. The recess 8b may be provided only on one side as long as the rotation direction is constant. This recess 8b is provided in order to prevent the protrusion 8c made of the high-density and high-sliding resin 4 from being worn by the sliding of the brush, and to prevent the powder from rising and riding on the segments 6a, 6b, 6c, 6d. It is.

FIG. 5 is a sectional view of a main part showing a relationship between a cylindrical commutator and a brush according to a second embodiment of the present invention. In FIG. 1, reference numeral 17 denotes a pair of noble metal thin plate or noble metal plated plate brushes. Reference numeral 18 denotes a cylindrical commutator on the outer periphery of which each segment 18a, 18b, 18c, 18d, which is divided into approximately four equal portions at approximately 90 degrees, is formed in a printed wiring pattern and is plated with a noble metal. 19 is a slit between each segment and a brush 1
In order to prevent short-circuiting due to 7, it is set relatively wide as described above. 19b is a concave portion, and 19c is a protrusion.

A structure of a flat coreless vibration motor using such an eccentric rotor 1 is as shown in FIG. That is, a thin shaft 10 is fixed to the center of the bracket 9 to rotatably support the eccentric rotor 1. The tip of the thin shaft 10 is the case 1 that constitutes the housing 11
The second through hole 12a is cut through the slidable washer 13 so as to withstand a side impact. The outer circumference of the eccentric rotor 1 is arranged via a gap by utilizing the small diameter of the magnet 5 to extend a convex portion 15 in a space 14 between the outer diameter of the magnet 5 and the inner circumference of the case 12. I am trying to. Since the center of gravity of such an eccentric rotor 1 largely moves toward the convex portion 15 on the outer periphery, it can contribute to the centrifugal force, that is, the amount of vibration. 16 in the figure
Is a flexible substrate for implanting the brush 7 and supplying power from outside.

Next, the principle of rotation of such a flat coreless vibration motor will be described with reference to FIGS. 6 to 8. Prior to that, the connection relationship will be described with reference to FIGS. The air-core armature coil 2 and the normal air-core armature coil 3 are connected at the end of winding.
The beginnings of the windings are respectively connected to the segments 6a and 6b of the commutator 6. The commutator 6 is configured such that the opposing segments 6a and 6c and 6b and 6d are short-circuited and have the same potential. Now, the eccentric rotor 1 is stopped at the position shown in FIG. 6 by the reluctance torque of the air-core armature coil 2 made of a magnetic plating wire. Current flows in the direction of the arrow, and a force is generated in the right direction in FIG. 6 to rotate according to the Fleming's left hand rule. When the commutator 6 and the eccentric rotor 1 advance by 90 ° to reach the position shown in FIG. 7, current flows in the coils 2 and 3 in the opposite directions. However, the poles of the magnets facing these coils are also exchanged, so that the framing left hand According to the law, the force is generated in the right direction, so that the rotation continues. When the commutator 6 and the eccentric rotor 1 further rotate by 90 ° to reach the position of 180 ° in FIG. 8, the position is different, but the same operation as in FIG. 6 is performed.

It should be noted that, as determined from FIGS.
At every 5 °, the brushes 7a and 7b come to the slit portion of the commutator 6 and ride on the projection 8c to become non-conductive. Since there is no stop at this slit due to the reluctance torque, there is no problem. Further, the shape and size of each coil need not always be the same, and the opening angles of the segments of the commutator 6 and the opening angles of the brushes 7a and 7b do not need to be completely every 90 °, and are intentionally slightly changed. By shifting, the non-energization time can be shortened.

Although the above embodiment has been described with reference to a two-coil type requiring relatively power, if power is not required, a single coil as shown in FIG. 9 may be used. FIG. 9 shows a third embodiment of the present invention. In FIG. 9, reference numeral 20 denotes an eccentric rotor in which one air-core armature coil 21 is biased to one side and integrally formed of a high-density and high-sliding resin 22. As this air-core armature coil, a coil formed by winding a magnetic plating wire of extremely thin plating is used similarly to the one described in the first embodiment. The air-core armature coil 21 formed by winding such a magnetic plating wire has a relatively large winding shaft and a smaller number of turns than other windings in order to avoid a large magnetic attraction force. Also, the magnet 23
Similarly, as described above, it has a donut-shaped disk shape and is N and S alternately magnetized into four poles equally. The width of the magnet 23, that is, the difference between the outer diameter and the inner diameter substantially coincides with the inner diameter portion of the effective conductor of the magnetically plated air-core armature coil 2. Therefore, the eccentric rotor 20 is driven by the reluctance torque of the magnetically plated air-core armature coil 21 so that the center of the air-core armature coil 21 is the magnet 23 as shown in FIGS. N pole and S
It will stop in the middle of the pole.

[0016]

As described above, according to the first aspect of the present invention, since the eccentric rotor is held at a specific position when stopped by the magnetic plating wire, it can be easily started by the Fleming left hand rule. . According to the second aspect of the present invention, it is possible to prevent the adjacent segments from being short-circuited by the brush at the slit portion. According to the third aspect of the present invention, the sliding powder such as resin is stored in the recess, so that a problem that the sliding powder appears on the segment surface can be prevented. According to the fourth aspect of the present invention, the hold by the reluctance torque can be reliably used, and the size of the magnet is reduced, which is advantageous in cost.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part showing a positional relationship between an eccentric rotor and a magnet showing a flat coreless vibration motor using a holding torque according to a first embodiment of the present invention.

FIG. 2 is a side sectional view of the first embodiment of the flat coreless vibration motor.

FIG. 3 is a back view for explaining the commutator in a view showing a cross section taken along the line AA in FIG. 2;

FIG. 4 is an enlarged sectional view of an essential part for describing a flat commutator and a brush which are main members of the motor.

FIG. 5 is an enlarged sectional view of an essential part for describing a cylindrical commutator and a brush according to a second embodiment of the present invention.

FIG. 6 is an explanatory view of the rotation principle of the motor of the present invention.

FIG. 7 is an explanatory view of the rotation principle of the motor of the present invention.

FIG. 8 is an explanatory diagram of the rotation principle of the motor according to the present invention.

FIG. 9 is a main part plan view showing a third embodiment of the present invention.

FIG. 10 is a sectional view showing a conventional flat vibration motor.

[Explanation of symbols]

Reference Signs List 1,20 Eccentric rotor 2,21 Air-core armature coil wound with magnetic plated wire 3 Normal air-core armature coil 4,22 High-density and high-slidability resin 5,23 Magnet 6,18 Commutator 7,17 Brush 8 , 19 slit

Claims (4)

[Claims] 1. An eccentric rotor having at least one air-core coil disposed on one side and a commutator attached thereto, and a pair of brushes for supplying power to the eccentric rotor, wherein at least a part of the air-core coil is formed of a magnetic plated wire. Then, the eccentric rotor is held at a specific position when stopped by utilizing the magnetism of the magnetic plating wire and the magnetism of the magnet facing the magnetized wire, and is adjacent to the slit of the commutator. A flat coreless vibration motor using holding torque, characterized in that a means for preventing the segments from being short-circuited by the brush is provided. 2. A means for preventing the segments adjacent to the slit of the commutator from being short-circuited by the brush is a projection disposed in the slit, and at least one of both sides of the projection is formed as a recess. Item 10. A flat coreless vibration motor using the holding torque according to item 1. 3. The flat coreless vibration motor using a holding torque according to claim 1, wherein the air-core coil comprises two coils, one of which is formed of a magnetic plated wire. 4. The width of the magnet (difference between outer diameter and inner diameter)
4. A flat coreless vibration motor using a holding torque according to claim 1, wherein the motor substantially coincides with an inner diameter of the coil.