JPH10248203A - Cored brushless vibrating motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cored brushless vibrating motor which is cored to obtain a cost merit and to make the vibration of the motor larger, by making the moving amount of the gravitational center of the motor for generating larger centrifugal force. SOLUTION: A cored brushless vibrating motor comprises a cored stator 4 having a plurality of armature coils 3, 3,... and a rotor R having a magnet 6 which is faced to the outside of the stator 4 with a clearance in between in the diametral direction and has a plurality of magnetic poles and a magnet holder 5 for holding the magnet 6. In addition, an unbalancing means 7 may be installed to at least one member constituting the rotor R.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cored type brushless vibration motor suitable for use as a silent information source of small wireless communication devices (pagers, portable telephones) and game machines.

[0002]

2. Description of the Related Art Conventionally, a small wireless communication device (pager,
As shown in FIG. 7, an eccentric weight W made of a tungsten alloy is provided on a rotation output shaft S of a small cylindrical DC motor M as a vibration motor used for a silent information source of a portable telephone. There is known an apparatus that uses a generated centrifugal force to obtain vibration.

[0003]

However, in the case where an eccentric weight is added to the output shaft, the set maker must consider the turning space of the eccentric weight, and the eccentric weight must be taken into account during rotation. The exposed weight is dangerous because the weight is exposed, and if an impact such as a direct drop is applied to the eccentric weight, the shaft may be deformed. In particular, in a flat type motor as shown in FIG. 8, since the eccentric weight must be thin,
The danger during turning is even higher, and the eccentric weight WW is
The size of the eccentric weight cannot be thickened, and there is a possibility that the eccentric weight may be inadvertently deformed in addition to the impact such as dropping.

For this reason, the present applicant has previously disclosed a cylindrical coreless type vibration motor in which the output shaft is eliminated and the built-in rotor is eccentric, as disclosed in Japanese Patent Application No. 2-309070 (US Pat.
155), and in a flat motor, Japanese Patent Application No. 63-11868 (U.S. Pat. No. 503,623) discloses that the eccentric weight is deleted and the rotor itself is eccentric to obtain vibration during rotation.
No. 9).

Since these motors do not have an output shaft and an eccentric weight, they are not restricted by design and are easy to use.
Although it has been well received by the market, for example, there is no danger during turning, it has a problem that the number of processing steps increases due to the coreless winding type. In order to vibrate the rotor itself with a cored type instead of the coreless winding type, the present applicant has previously disclosed all three salient pole type cores as shown in Japanese Patent Application No. 4-286978 (U.S. Pat. No. 5,341,057). One that is biased to one side (within 180 degrees) is proposed. However, since these motors are all rectifier devices, it is necessary to make them brushless to extend their life. The present applicant has previously proposed a cylindrical coreless type brushless vibration motor as disclosed in Japanese Patent Application No. 3-149906 (U.S. Pat. No. 5,036,239).

An object of the present invention is disclosed in Japanese Patent Application No. 3-14990.
No. 6 (U.S. Pat. No. 5,036,239), which was created to further improve the cored structure. By making the cored, it is advantageous in terms of cost, and the displacement of the center of gravity for generating centrifugal force can be increased to increase vibration. A cored brushless vibration motor is provided.

[0007]

The above object can be attained by providing at least one member constituting the epicyclic rotor with unbalance means. This makes it possible to increase the vibration with a simple configuration.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As one embodiment of the present invention, as shown in claim 1, a cored stator having a plurality of armature coils and a radial gap provided outside the cored stator. The rotor may include a magnet having a plurality of magnetic poles and a magnet holder for holding the magnet, and at least one member constituting the rotor may be provided with an unbalance means. In this way, a large vibration can be obtained with a very simple configuration. As a specific embodiment, as described in claim 2, the unbalance means can be easily started with a simple configuration if a part of the magnet holder is cut out. In another embodiment, the magnet holder is made of a lightweight resin, and a crescent-shaped high-specific-gravity member as viewed from a plane is embedded as the unbalance means, thereby reducing the weight. Then, an unbalance means is obtained. Claim 4
As shown in (1), a part of the magnet may be cut out and used as the unbalance means. In this case, the vibration can be increased. Furthermore, in these embodiments, if a cover for protecting the rotor is provided as a part of the stator as described in claim 5, there is no danger, which is advantageous. In these embodiments, the structure can be simplified by fixing the shaft to a part of the stator and adopting the magnet holder on the bearing side.

[0009]

FIG. 1 shows a configuration of a flat shaft-fixed cored brushless vibration motor as a first embodiment of the present invention.
This will be described with reference to the cross-sectional views of the main parts shown in FIG. In the figure, a burring hole 1a is arranged at the center of a plate-shaped stator base 1, and a shaft 2 is press-fitted into the burring hole 1a. Further, a stator core 4 having an armature coil 3 # wound around a plurality of, for example, six salient poles 4a # via a core cover, as shown in FIG.
Are attached via a plurality of cut-and-raised portions 1b. The stator core 4 is configured so that two silicon steel plates are bent in opposite directions at the blade portion 4b so that magnetic flux can be efficiently picked up. Each of the armature coils 3
The {terminal 3a} is connected to the flexible substrate 1c disposed on the stator base 1 so that power is supplied from outside. A magnet holder 5 made of a highly slidable resin is rotatably mounted on the shaft 2. That is, the magnet holder 5 itself is a bearing. As shown in FIG. 2, the magnet holder 5 has a shallow cylindrical shape having a plurality of (for example, eight in this case) field magnetic poles inside the blade portion 4b of the stator core 4 through a radial gap as shown in FIG. A magnet R is integrally formed with a crescent-shaped high-specific-gravity metal body 7 arranged outside to form a rotor R. A space E is formed on the opposite side of the high specific gravity metal body 7. For this reason, since the center of gravity of the rotor R moves toward the crescent-shaped high-specific-gravity metal body 7, vibration is generated during rotation. In the drawing, reference numeral 8a denotes a thrust washer, and 8b denotes a thrust washer which also serves to prevent the rotor R from coming off. In this embodiment, the outer cover is omitted because there is no protrusion at the turning portion of the rotor R. However, this cover can be attached as described later.

FIG. 3 is a sectional view of a main part of a shaft-rotating cored brushless vibration motor as a second embodiment of the present invention. In the figure, a bearing holder 12 is provided at the center of a bracket 11. The bearing holder 12 includes a rising portion 12b which is cut and raised by press working from the bracket itself while leaving the receiving portion 12a. Inside the bearing holder portion 12, a sintered oil-impregnated bearing 13 is provided with a backing plate 13
a and a stator core 4 having an armature coil 3 # wound around a plurality of (for example, six in this case) salient poles 4a # as described above. On the other hand, the rotor RR has a magnet holder 55 having an anchor-shaped plane as shown in FIG. 4 and an inner side fixed to the magnet holder 55 and facing the blade portion 4b of the stator core 4 through a radial gap. And a burring hole 55a arranged at the center of rotation of the magnet holder 55. The burring hole 55a has a plurality of (for example, eight in this case) field magnetic poles.
The shaft 22 is mounted by press fitting. The shaft 22 has one end rotatably supported by the sintered oil-impregnated bearing 13 and the other end rotatably supported by the sintered oil-impregnated bearing 14 disposed in the case 9 also serving as a cover.

FIG. 5 is a plan view of an essential part showing a modified example of the above embodiment. In order to exert the power of the magnet 6, the magnet holder 56 is made of a magnetic material and the outer periphery of the magnet 6 is also used as a return path plate. It is made into a case type to cover. In this case, in order to increase the amount of eccentricity, a large through hole 56a is formed on the side opposite to the center of gravity. In this case, a part 6a of the magnet 6 may be cut off as shown by an imaginary line within a range in which the magnet 6 can be started. This way,
The movement of the center of gravity can be increased with good efficiency.

FIG. 6 is a side view of a main part of a core showing a configuration for facilitating starting as another modification of the above embodiment. That is, a notch 4c may be formed in the blade portion 4b of the stator core 4 to improve the cogging torque to facilitate starting.

Although the description has been made of the case where the number of the cores is two, it is possible to adopt a single core for thinning, or an axially long one in which several tens are laminated for generating power. Needless to say.

In order to drive such a brushless vibration motor, a known sensorless system using back electromotive force detection is used.

[0015]

According to the present invention, there is provided a cored brushless vibration motor having the above-described structure, which is made cored, which is advantageous in cost, and which has a large amount of movement of the center of gravity for generating centrifugal force. can do.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part of a fixed-shaft cored brushless vibration motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of an essential part taken along line AA of the embodiment.

FIG. 3 is a sectional view showing a main part of a shaft-rotating cored brushless vibration motor according to a second embodiment of the present invention;

FIG. 4 is a plan view of a main part of the rotor of the embodiment.

FIG. 5 is a cross-sectional view of a main part showing a modification of the embodiment.

FIG. 6 is a side view of a main part showing a modification of the stator core.

FIG. 7 is a perspective view of a conventional vibration motor.

FIG. 8 is a side view of another conventional vibration motor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator base 2, 22 axis 3 Armature coil 4 Stator core 5, 55 Magnet holder 6, 66 Magnet R, RR rotor 7 High specific gravity metal body 8a, 8b Thrust washer 9 Case

Claims (6)

[Claims] 1. A cored stator having a plurality of armature coils, a magnet having a plurality of magnetic poles facing the outside of the cored stator through a radial gap, and a magnet holder holding the magnet. A cored brushless vibration motor comprising a rotor having at least one member provided with an unbalance means. 2. The cored brushless vibration motor according to claim 1, wherein said unbalance means is formed by cutting out a part of a magnet holder. 3. The cored brushless vibration motor according to claim 1, wherein the magnet holder is made of a lightweight resin, and a crescent-shaped high specific gravity member as viewed from a plane is embedded as an unbalance means. 4. The cored type brushless vibration motor according to claim 1, wherein a magnet is used as said unbalance means. 5. The cored type brushless vibration motor according to claim 1, wherein a cover for protecting the rotor is provided as a part of the stator. 6. The cored brushless vibration motor according to claim 1, wherein the shaft is fixed to a part of the stator, and the magnet holder is on the bearing side.