JP3166707B2 - Brushless vibration motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital watch
The present invention relates to a brushless vibration motor for notifying, by vibration, that an individual alarm function or an individual call signal has been received in an analog wristwatch, pager, mobile phone, or the like.

[0002]

2. Description of the Related Art Conventional brushless vibration motors include:
One described in Japanese Patent Application Laid-Open No. 3-107347 is known. FIG. 3 shows a conventional brushless vibration motor. In FIG. 3, a stator 1 is configured by arranging coils 2 of a plurality of phases on a stator substrate 3, and a housing 6 having a bearing 4 and a thrust plate 5 fixed to the center of the stator 1. On the other hand, the rotor is composed of a driving magnet 7 disposed in the coil 2 of the stator 1 with a gap, and a rotating yoke 8 mounted on the stator substrate 3 through the gap.
And the rotor frame 9 has a rotating shaft 10 fixed at the center, and the bearing 4 rotatably supports the rotating shaft 10.
The coils 2 of a plurality of phases are sequentially energized by a sensorless drive circuit (not shown) to generate a rotational torque on the rotor. The weight 11 is mounted asymmetrically with respect to the rotating shaft 10 and generates vibration by rotation of the rotor. The brushless vibration motor is configured as described above.

FIG. 4 shows a top view of the rotor. In FIG. 4, the weight 1 attached to a part of the outer peripheral surface of the driving magnet 7
1 is a vibration generating means. Since a small brushless motor is driven without a position sensor, a sensorless drive circuit that can reduce the size of the motor is often used.

[0004]

However, in the conventional structure, vibration is generated by attaching the weight 11 to a part of the outer peripheral surface of the driving magnet 7, but the moment of inertia of the rotor itself is not sufficient to generate vibration. If the rotor does not contribute, and the rotor has a large moment of inertia, start-up failure may occur when sensorless control is performed. Further, since the starting time of the motor is long, the current consumption is large. In particular, in the case of a vibration motor whose main operation is intermittent operation and battery operation, the start-up time and current consumption are serious problems.

The present invention solves such a conventional problem. In addition to reducing the rotor inertia moment without reducing the effect of vibration generation, the present invention not only shortens the start-up time but also reduces the current consumption of the motor. An object of the present invention is to realize an excellent brushless vibration motor having a small size and a light weight motor.

[0006]

According to a first aspect of the present invention, there is provided a brushless vibration motor having a cylindrical driving magnet mounted on an inner surface of a rotor frame, and a rotating shaft fixed to the rotor. A brushless motor having an armature having a multi-phase coil disposed opposite to the inner periphery of the driving magnet, wherein a rotor having a plurality of holes formed in a top surface of the rotor frame; It is provided with.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention
The mounted cylindrical drive magnet and this rotor
A rotating shaft fixed to the rotating magnet;
Armature having a multi-phase coil arranged facing the circumference
Outer rotor type brush with radial gap configuration
In the less motor, a plurality of
Holes, and the vibration generating means
The brushless vibration mode
Time notification on a watch, pager / mobile phone call
It is installed for information. According to the above configuration, the low
Motor inertia moment and the motor itself
Can be promoted.

[0008]

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

FIG. 1 shows a cross section of a brushless vibration motor according to the present invention. In FIG. 1, a plurality of phases of a coil 2, a stator substrate 3, a bearing 4, a thrust plate 5, and a housing 6 constituting a stator 1 are the same as those of the conventional example, and therefore description thereof will be omitted. On the other hand, the rotor is provided with a plurality of coils 2 of the stator 1 with a gap therebetween, and has a cylindrical driving magnet 7, and a weight 11 made of a high-density resin or the like on the outer periphery of the rotor frame 9. Rotating shaft 10 fixed to
The bearing 4 rotatably supports the rotating shaft 10. The brushless vibration motor is configured as described above.

FIG. 2 shows a top view of the rotor. In FIG. 2, a plurality of circular holes 12 are formed on the top surface of the rotor frame 9.
Are provided point-symmetrically with respect to the rotating shaft 10, and the weight 1 made of a high-density resin
1, the center of gravity of the rotor is shifted from the center of rotation toward the weight 11, so that the rotation of the rotor 7 causes vibration.

With this configuration, the motor has a magnetic circuit having a radial gap, so that the rotor frame 9 does not function as a magnetic circuit for shielding magnetic flux found in a surface-facing motor. Even if a plurality of holes 12 are provided on the top surface of the rotor frame 9, the characteristics of the motor will not be degraded because it is simply a necessary component in structure. Rather, by providing a plurality of holes 12, the moment of inertia of the rotor can be reduced without reducing the effect of vibration generation, and controllability is improved by shortening the start-up time,
The current consumption is reduced. Further, the provision of the plurality of holes 12 makes it possible to provide a brushless vibration motor in which the weight of the motor is reduced.

In this embodiment, the weight 11 is attached to the outer periphery of the rotor frame 9, but the same effect can be obtained by attaching the weight to the top surface of the rotor.

[0013]

As is clear from the description of the above embodiment,
According to the first aspect of the present invention, the brushless motor can reduce the inertia moment of the rotor without reducing the effect of vibration generation, not only shorten the start-up time, but also reduce the current consumption of the motor and reduce the weight of the motor. A vibration motor can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a flat brushless vibration motor according to a first embodiment of the present invention.

FIG. 2 is a top view of the rotor frame according to the first embodiment of the present invention.

FIG. 3 is a sectional view of a conventional brushless vibration motor.

FIG. 4 is a top view of a rotor of a conventional brushless vibration motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 2 Coil 3 Stator board 4 Bearing 5 Thrust plate 6 Housing 7 Driving magnet 8 Rotating yoke 9 Rotor frame 10 Rotating shaft 11 Weight 12 Circular holes provided on the top surface of rotor frame

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02K 21/22 H02K 21/24

Claims (4)

(57) [Claims] 1. A cylindrical driving magnet mounted on the rotor frame inner surface, and a rotating shaft fixed to the rotor, the coils of a plurality of phases arranged in the inner periphery facing the driving magnets Radial armature with armature
An outer rotor type brushless motor having a cap configuration , wherein a plurality of holes are provided in a top surface of the rotor frame, and a vibration generating means is arranged on an outer peripheral portion of the rotor frame. 2. The brushless vibration motor according to claim 1,
A portable mobile device equipped. 3. The brushless vibration motor according to claim 1,
Equipped pager. 4. The brushless vibration motor according to claim 1,
Mobile phone equipped.