JPH08308169A - Axial gap coreless vibrating motor - Google Patents

Abstract

PURPOSE: To obtain a desired vibrational amount with an axial gap coreless vibrating motor without reducing the thickness of its rotor by starting the winding of an air-core coil after ensuring a sufficiently large inside diameter and making the termination of the coil easier by integrally constituting the rotor of a resin so that part of a weight composed of a soft high-density member can be contained in the thickness part of the rotor. CONSTITUTION: A plate commutator 17 composed of a printed wiring board is uniformly added to the gap side of a rotor 15 on a casing 14 side with a weight 16 composed of a half-moon shaped high-density member on one side. In the rotor 15, three air-core coils 15a, 15b, and 15c are arranged on the commutator 17 at regular intervals of 120 deg., but the inside diameter of the coil 15a arranged on the opposite side of the weight 16 is made larger than those of the other coils 15b and 15c and the wound outside diameter of the coil 15a in the radial direction is made nearly equal to those of the other coils 15b and 15c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial air gap type motor, particularly a coreless vibration motor having an eccentric weight incorporated therein, which is used as a silent call means of a portable radio calling device (trade name: pager).

[0002]

2. Description of the Related Art As a silent call means for a pager, an eccentric weight W made of a tungsten alloy is arranged on an output shaft S of a cylindrical motor M as shown in FIG. 6, and a difference in centrifugal force of the eccentric weight W is used during rotation. It is known to generate vibrations.

However, in the case where the eccentric weight W is added to the output shaft, there is a problem that the turning space of the eccentric weight must be taken into consideration in the design on the set manufacturer side.

In order to overcome the above drawbacks, an eccentric weight is deleted, and a flat coreless vibration motor having an eccentric rotor itself is disclosed in Japanese Utility Model Application No. 63-1111868 (USP5036).
239) and Japanese Patent Application No. 4-295503, whose application has been changed, have been proposed by the present applicant. That is, as shown in FIG. 4, the three armature coils 9a, 9b, and 9c are arranged so as not to overlap each other and are biased to one side so that the planes are substantially fan-shaped, and are integrated with the resin 11. A molded rotor R is used, and the eccentric rotor R is configured as a flat coreless motor as shown in FIG. 5 so that vibration is generated during rotation. That is, 1 is a shallow case, 2 is a bracket crimped to the opening of this case, 3 is a magnet arranged on this bracket, which gives a magnetic field to the rotor R, and a terminal inside the magnet via a brush base 4. 5 has a brush 6 planted therein. Also, in the figure, 7 is a shaft,
8 is a rotor holder, 9 is an armature, 10 is a flat plate commutator, 11 is a resin that constitutes the rotor R, 12a and 12b are bearings that rotatably support the shaft, and 13
Reference numerals a and 13b are thrust washers.

[0005]

The eccentric rotor itself which produces vibrations has a diameter of 15 mm.
With flat coreless motors of mm or more, the amount of eccentricity can be relatively large, so it is popular in the market, but the diameter is 12 mm.
When the following ultra-compact size is required, the amount of movement from the center of the center of gravity is small, and the desired amount of vibration cannot be obtained unless the motor is thickened, so auxiliary weights are required.
However, when the auxiliary weight is simply attached to the rotor by adhesion or the like, a problem of impact resistance is likely to occur. In other words, mobile devices are always exposed to the risk of falling due to mishandling, so it is necessary to give due consideration to impact resistance.However, since the weight acceleration of the mobile device is added to the weight weight, the vibration acceleration is strong, and therefore only adhesion is required. Then it becomes a problem. Moreover, since the three air-core coils are biased to one side, the inner diameter must be extremely small, which causes a problem that it is very difficult to connect the winding start terminal of each coil.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a micro flat coreless motor having a diameter of 12 mm or less so as to secure a sufficient inner diameter of an air-core coil to facilitate the treatment of a winding start terminal and to sacrifice a small thickness. The purpose is to be able to obtain a desired vibration amount. Another object of the present invention is to ensure impact resistance by devising an eccentric weight and firmly fixing it to the rotor. Still another object of the present invention is to improve centrifugal force by devising an armature coil of a rotor.

[0007]

According to the invention as set forth in claim 1, the above object is to provide a casing, a rotor having a plurality of air-core coils integrated with resin inside the casing, and a rotor supported on a shaft. A commutator attached to the rotor, a magnet facing the rotor through an axial gap, a magnet placed on the magnet, and a pair of brushes arranged inside the magnet and assembled to the casing. In the axial air gap type coreless motor equipped with the bracket, a weight made of a flexible high-density member is arranged on one side of the rotor opposite to the magnet side, and the pressure during molding is used when the rotor is integrated with resin. And a part of the weight made of the flexible high density member is included in the thickness portion of the rotor. More specifically, as in the second aspect of the present invention, the weight made of a flexible high-density member can be achieved by using an unsintered product obtained by temporarily forming a tungsten alloy with a binder. Further, as in the invention described in claim 3, the weight made of the flexible high density member can be achieved by having the notch for deformation. Further, as in the invention described in claim 4, the weight made of a flexible high-density member can be achieved by having an adhesive layer made of an adhesive material. Further, as the structure of the rotor, as in the invention described in claim 5, it can be achieved by reducing the weight of the rotor on the side where the weight made of the flexible high-density member is not arranged. Furthermore, as a means for reducing the weight of the rotor on the side where the weight made of a flexible high-density member is not arranged, the inner diameter of the air-core coil is increased to reduce the number of turns as in the invention described in claim 6. Can be achieved with.

[0008]

According to the above-mentioned means for achieving the above object, since a part of the weight made of the flexible high density member is included in the thickness of the rotor, the flexible high density member is firmly attached to the rotor. Can be integrated. According to the means for achieving the above object of the present invention, since the weight made of the flexible high-density member can be used as it is in the unsintered state of the tungsten alloy, it is possible to save the time and labor for sintering, and therefore the cost is reduced. Will be advantageous. According to the above-mentioned means for achieving the object, the weight made of the flexible high-density member can be easily expanded by the deformation slit and the molding is facilitated. According to the above means for achieving the above object, since the adhesive layer is provided, it is possible to insulate the coil from the coil and to secure a large fixing force. According to the above-mentioned means for achieving the above object, the amount of movement of the center of gravity is increased, and the amount of vibration can be increased. According to the object achieving means as set forth in claim 6, since the winding portion extends in the longitudinal direction in the longitudinal direction by increasing the inner diameter of the air-core coil, the virtual line of the reference electrical opening angle is substantially the effective conductor portion of the air-core coil. Since it comes to the center, a substantial effective conductor portion can be obtained for a long time. Therefore, even if the number of turns is reduced, the torque can be effectively obtained and only the weight can be reduced.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the structure of an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view of an embodiment of an axial gap type flat coreless vibration motor of the present invention, and FIG. 2 is a perspective view of an essential part of a rotor in the embodiment. Further, FIG. 3 is a perspective view of an essential part of a flexible high-density member adopted in the same embodiment. In the figure, reference numeral 14 denotes a shallow cylindrical casing, which has a shaft holding portion 14a formed by burring the central portion inward.
Is provided. A shaft 77 having a diameter of about 0.8 mm and having one end press-fitted therein is arranged in the shaft holding portion 14a. The shaft 77 has three air-core coils 15a and 15b.
A rotor 15 is integrally rotatably supported on the rotor 15 and 15c by a high-sliding resin J. On the gap side of the rotor 15 with the casing 14, a weight 16 made of a substantially half-moon type high density member is integrally formed on one side, and a flat plate commutator 17 made of a printed wiring board is uniformly attached to the other side. It is set up. Reference numeral 33 is a ring-shaped neodymium magnet which faces the rotor 15 through a slight air gap in order to apply a magnetic field to the rotor 15. The magnet 33 is equally divided into four poles at an opening angle of 90 degrees and is mounted on the bracket 22. Inside the 33, a brush base 44 is integrally molded with the bracket 22 with resin. A terminal 55 is planted in the brush base 44, and a pair of brushes 66 whose base ends are spotted are arranged on the terminals 55. The free ends of the brushes 66 are the flat plate commutator 1 described above.
It is adapted to be slidably contacted with 7 at an appropriate pressure.

As shown in FIG. 2, the rotor 15 has three air core coils 15a, 15b and 15c equally spaced at 120 ° intervals on a thin flat plate commutator made of a printed wiring board. The inner diameter of the air-core coil 15a arranged on the opposite side of the weight 16 made of a high-density member is larger than that of the other two air-core coils 15b and 15c, and the outer diameter in the winding end radial direction is the same as that of the other coil. It is almost the same. Therefore, the air-core coil 15a has a smaller number of turns and is lighter in weight than the others, so that the moving amount of the center of gravity extends to the weight 16 side. The number of effective conductors of this air-core coil 15a is equal to that of the other air-core coils 15b,
Although it is less than that of 15c, since the coil freely extends in the longitudinal direction, the virtual line of the reference electrical opening angle (opening angle of the magnetizing magnetic pole = 90 °) passes through the center of the effective conductor portion of the coil, and thus is substantially The effective conductor length does not greatly deteriorate.

The weight 16 made of a flexible high density member, which is a main component of the present invention, for example, a tungsten alloy that has been preformed with a binder and is not sintered is:
Since the electrical resistance is comparatively large, there is no concern about eddy current, and as shown in FIG. 3, it is formed as a semi-moon shape and is formed in a half-moon shape.
And 16c are provided, and when integrally molded with the high-sliding resin J, a gate port is provided at the cut groove 16a, and 16b and 16c are located at the inner diameters of the air-core coils 15b and 15c. Notch 16
The portions a, 16b and 16c are deformed and embedded within the thickness of the rotor 15 by press fitting during injection molding. Therefore, the weight 16 is not likely to be detached from the rotor 15 even when it is dropped or the like, and is partially replaced with the highly slidable resin, so that the moving amount of the center of gravity can be large. In the figure, reference numeral 18 denotes an adhesive layer made of an acrylic adhesive material, which has the function of insulating the air-core coils 3b and 3c from the weight 16 in addition to the function of increasing the bonding strength.

[0012]

[Other Embodiments] In the above embodiments, a weight made of unsintered tungsten alloy is shown as an example of a flexible high-density member that is free from eddy currents. It may be a soft metal.
Further, regarding the notch for deformation, it is easy to smooth the inflow of the resin at the time of injection molding, but a notch may be used instead of the groove, and it is not necessary to particularly provide the notch if deformed by an injection molding die. Furthermore, as the air-core coil, one weight is lighter than the others, but three air-core coils may be equivalent as long as the weight size can be increased. In the above embodiment, the shaft is fixed, but the shaft may be integrated with the rotor by two bearings as in the conventional case.

[0012]

Since the present invention has been described above,
Even if it is a flat coreless motor in which the air-core coil with a diameter of 12 mm or less is divided into three equal parts by a weight made of a flexible high-density member, the inner diameter is sufficiently secured to facilitate winding start and end treatment, the amount of movement of the center of gravity Since a large value can be obtained, the desired amount of vibration can be obtained without sacrificing the thickness.
Since the weight is made of a flexible high density member, a part of the weight can be cut into the thickness of the rotor by the pressure of the molding. Therefore, it is possible to achieve the initial purpose such as the effect of being able to be firmly fixed and ensuring the impact resistance.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of an axial gap type flat coreless vibration motor of the present invention.

FIG. 2 is a perspective view of a main part of an internal rotor in FIG.

FIG. 3 is a perspective view of a main part of main parts in FIG.

FIG. 4 is a plan view of a rotor of a conventional flat coreless vibration motor.

FIG. 5 is a sectional view of a conventional flat coreless vibration motor incorporating the same rotor.

FIG. 6 is a perspective view of a general cylindrical coreless vibration motor to which a conventional eccentric weight is externally attached.

[Explanation of symbols]

 14 Casing 77 Shaft 15 Rotor 15a, 15b, 15c Air-core coil 16 Weights 16a, 16b, 16c made of flexible high-density material Cut groove 17 Flat plate commutator 18 Adhesive layer 33 Ring magnet 44 Brush base 55 Terminal 66 Brush

Claims (6)

[Claims] 1. A casing, a rotor in which a plurality of air-core coils are integrated with resin inside the casing, and which is supported by a shaft, a commutator attached to the rotor, and an axial gap in the rotor. In the axial air gap type coreless vibration motor including a magnet facing through the magnet, a pair of brushes arranged inside the magnet, and a bracket assembled to the casing, the rotor including: A weight made of a flexible high-density member is arranged on one side of the anti-magnet side of the rotor, and a part of the weight made of the flexible high-density member is utilized by utilizing the pressure during molding when the rotor is integrated with resin. The axial gap type coreless vibration motor is characterized in that it is included in the thickness portion of the. 2. The axial void type coreless vibration motor according to claim 1, wherein the weight made of a flexible high-density member is an unsintered body obtained by temporarily forming a tungsten alloy with a binder. 3. The axial void type coreless vibration motor according to claim 1, wherein the weight made of a flexible high density member has a notch for deformation. 4. The weight made of a flexible high-density member is provided with an adhesive layer made of an adhesive material.
An axial air gap type coreless vibration motor according to any one of 1. 5. The axial air gap type coreless vibration motor according to claim 1, wherein a weight of the rotor, which is made of a flexible high-density member, on which the weight is not arranged is lightened. 6. The axial air gap type coreless vibration motor according to claim 1, wherein at least one of the lightening means has an air core coil having a large inner diameter and a small number of turns.