JP2002143767A - Eccentric weight for small-size brushless vibration motor and small-size brushless vibration motor using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent both the size and the amount of vibration from being sacrificed by enabling an eccentric weight to form at least a weak magnetic circuit and by directly fixing the weight to a magnet. SOLUTION: An eccentric weight (W) comprising a tungsten alloy and having a pure iron plating (M) formed on the surface is used. An eccentric rotor (R) is prepared by forming a first cut-off section (5b) on a rotor case (5) for holding a magnet (6); directly fixing the eccentric weight (W) to the magnet by eccentrically putting the weight into the first cut-off section; and forming, at the opposite side of the rotor case (5), a second cut-off section (5c) as a weight reduction means and also as a magnetic circuit homogenization means. An objective brushless vibration motor has the eccentric rotor (R), a stator (S) for driving the rotor, and a stator base (1) for rotatably supporting the rotor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an eccentric weight for a small-sized brushless vibration motor and a small-sized brushless vibration motor using the same, which is suitable for use as a silent notification means of a mobile communication device.

[0002]

2. Description of the Related Art Conventionally, as a flat small brushless vibration motor, the applicant of the present invention has previously disclosed Japanese Utility Model Laid-Open No. 4-137463 (U.S. Pat. No. 2,549,357) and Japanese Patent Application Laid-Open No. 10-248.
No. 203 is proposed. Further, as a similar one, there has been proposed a rotor case in which the side surface of a rotor case is turned off and eccentric as shown in Japanese Patent Application Laid-Open No. 11-98761. However, in such a configuration, since the material of the normal rotor case is steel having a specific gravity of about 7.9, the amount of eccentricity is small and is not practical. For this reason, a shallow cylindrical magnet is arranged inside a rotor case constituting a magnetic circuit as a small brushless vibration motor, and a semi-cylindrical tungsten alloy is formed outside the rotor case.
No. 173, as shown in FIG.

[0003]

However, in such a structure, since the eccentric weight portion must protrude from the turning outer diameter of the rotor, this danger is avoided and the cover is attached so as to be easily handled. It has become. Therefore, there is a dislike that the size becomes large in the radial direction. That is, as the eccentric weight is increased in order to increase the vibration amount, there is a problem that the size in the radial direction is sacrificed. As a countermeasure against this, there is conceivable a means in which the side surface of the rotor case is cut out and the eccentric weight is stored here. By the way, since the eccentric weight is a copper tungsten alloy,
Since it is usually a non-magnetic material, a magnetic circuit cannot be formed as it is.

Therefore, the present invention is directed to an eccentric weight in which the eccentric weight has means for forming a magnetic circuit at least to be directly fixed to the magnet so that the size is not sacrificed and the amount of vibration is not sacrificed. And a small brushless vibration motor using the same weight.

[0005]

An eccentric weight for a small brushless vibration motor which solves the above-mentioned problems is achieved by using a tungsten alloy in which a magnetic material is integrated at least in part as described in claim 1. it can. The specific structure of the weight is as follows. The magnetic body has a surface plated with iron, or the magnetic body contains an iron powder and is sintered. It is better to do it. A small vibration motor using such an eccentric weight is provided with a first notch provided in a rotor case holding the magnet as described in claim 4, and the eccentric is provided in the first notch. An eccentric rotor in which at least a part of the weight is stored and directly fixed to the magnet, and the rotor case is provided with lightening means on the opposite side of the eccentric weight, a stator for driving the eccentric rotor, and the eccentric rotor This can be attained by providing a stator base rotatably supported by. Specifically, in the motor, the first cutout portion is provided on a side surface of a rotor case, and a mounting guide portion for the eccentric weight is provided in the rotor case. It is preferable to provide an eccentric rotor having a second notch provided on the side surface of the rotor case opposite to the eccentric weight as the means for forming the eccentric weight. In order to form an axial gap type motor, the first cutout is provided in the ceiling of the rotor case in the form of a fan which is widened when viewed from a plane. An eccentric rotor having substantially the same shape as the eccentric weight inserted into the notch portion and directly adhered to the axial gap type magnet, and an eccentric rotor having a lightening means provided on the rotor case opposite to the eccentric weight, and driving the eccentric rotor. This can be achieved by providing a stator having a stator base and a stator base rotatably supporting the eccentric rotor and having terminals arranged on the side. Specifically, the motor preferably has an eccentric rotor having a second notch provided on the ceiling of the rotor case on the opposite side of the eccentric weight, as the weight reducing means. . The motor may also be
As shown in the figure, the stator base is formed of a resin in which a plurality of terminals are independently integrated except for a common terminal, and a skeleton made of a magnetic material is integrated, and a part of the magnetic material is used in the axial direction. It is desirable to be configured to receive the magnetic flux of the air gap type magnet. These motors may be provided with a cover that covers the eccentric rotor, wherein the terminals are provided so as not to be outward at square corners.

According to the first aspect of the present invention, a simple function of the magnetic circuit of the magnet is achieved, and the magnet can be easily held when directly bonded to the magnet. According to the second aspect of the present invention, the present copper-tungsten alloy can be simply subjected to a surface treatment, so that it can be simplified. According to the third aspect of the present invention, a part can be replaced by iron powder instead of copper. According to the fourth aspect of the present invention, it is possible to provide a motor whose size is not sacrificed even when an eccentric weight is added. According to the fifth aspect of the invention, the weight of the eccentric rotor can be reduced, and the magnetic imbalance can be reduced. According to the invention as set forth in claim 6, the eccentric weight and the magnet can be easily bonded, and the weight of the eccentric rotor can be reduced. According to the seventh aspect of the invention, the eccentric rotor can be reduced in weight and magnetic imbalance can be reduced. In the invention described in claim 8, the magnetic attraction force can be controlled by the arrangement structure of the terminals made of a magnetic material. According to the ninth aspect, chucking can be easily performed, heat resistance can be obtained by the cover, and reflow soldering can be performed.

[0007]

FIG. 1 is a plan view showing the first embodiment as an example of use of an eccentric weight according to the present invention, and is a plan view showing the inside of a small brushless vibration motor of a radial gap type cored type. FIG. 2 is a longitudinal sectional view of the motor of FIG. FIG. 3 is a plan view showing the inside of a modification of the motor shown in FIG. FIG. 4 shows a second example of the use of the eccentric weight of the present invention.
FIG. 1 is a longitudinal sectional view of a small brushless vibration motor of an axial gap type coreless system, showing an embodiment of the present invention. FIG. 5 is a plan view of the inside of the motor of FIG.

Hereinafter, the configuration of the present invention will be described based on each embodiment shown in the drawings. 1 and 2 show a three-phase radial gap type cored type small brushless vibration motor, that is, a shaft 1 constituting a part of a housing H.
h, a stepped shaft support 1a is burred from the skeleton 1h at the center of a square stator base 1 made of a heat-resistant resin formed by outsert molding, and fixed by press-fitting the shaft 2 into the shaft support 1a. . By attaching the stator core 4 in which the armature coils 3a, 3b, 3f are wound around the salient poles 4a, 4b, 4f via a core cover (not shown) to the shaft supporting portion 1a, the three-phase six poles are formed. As a stator S. Part of the diaphysis 1h independently forms a terminal portion 1t except for the common terminal 1k. In addition, the armature coil is usually formed by connecting facing armature coils in series,
The terminal is connected to an exposed portion 1u connected to each terminal 1t. On the other hand, the rotor R comprises a shallow cylindrical rotor case 5 provided with a bearing 5a at the center and a shallow cylindrical magnet 6 fixed inside the rotor case.
A first notch portion 5b and mounting guide portions 5bb at both ends of the first notch portion 5b, and a light-weight magnetic circuit adjusting means on an opposite side surface of the first notch portion 5b via the bearing 5a. A second notch 5c is provided. The size of the second cutout portion 5c is determined in accordance with a return path function by a magnetic portion of the eccentric weight described later. In order to further reduce the weight, a third half-moon shaped notch 5d is formed on the ceiling opposite to the first notch 5b. The semi-cylindrical eccentric weight W, which is a feature of the present invention, is fitted into the first cutout portion 5b, and is attached directly to the outer periphery of the shallow cylindrical magnet 6 by bonding or the like, and is disposed at the center. The shaft is rotatably mounted on the shaft via a bearing 5a. Here, the eccentric weight W is formed by applying a pure iron plating Wa to a copper-tungsten alloy to a thickness of about 30 μm, and furthermore, the surface is subjected to a rust-proof treatment. Here, the magnet 6 has eight magnetic poles alternately magnetized by NS so that a good start can be obtained. Since the eccentric rotor R is exposed, if it is inconvenient to mount the eccentric rotor R on the device, cover the eccentric rotor R with a thin non-magnetic stainless steel cover C having a heat insulating effect as shown by an imaginary line. It may be. The cover C is attached to the square stator base 1 by bending the skirt Ca insulated from the terminal portion 1t. In this way, even if there is some leakage magnetic flux of the magnet, there is no possibility that the rotation of the rotor will be hindered, and the magnet can be insulated even in the reflow soldering. Further, the eccentric weight may be a material obtained by mixing and sintering fine iron powder instead of pure iron plating. The driving method of such a configuration is 3
A phaseless unipolar or bipolar sensorless system is used. Since the driving principle is well known, the description is omitted.

Hereinafter, modifications and other embodiments of the above embodiment will be described. In some cases, the same members or substantially the same members having the same functions are denoted by the same reference numerals, and description thereof will be omitted. is there. FIG. 3 shows the first modified example, in which a part of a shallow cylindrical magnet 66 made of resin as the eccentric rotor R1 has an open angle (here, 90 degrees) biting portion having no problem in starting. A notch 66a having iron powder and a density (specific gravity) of 1
An eccentric weight W1 made of a polyamide resin made of about three tungsten alloys is attached by integral molding with a shallow cylindrical magnet 66 made of the resin. Also on the opposite side of the eccentric weight W1, the side surface of the rotor case 55 is cut out so as to have a biting portion 55e, and the shallow cylindrical magnet 6 made of resin
Part of 6 is to cut into. That is, the rotor case 55 and the rotor case 55 are integrally formed. In the figure,
Reference numeral 55f denotes a through hole provided in the ceiling of the rotor case 55 for connecting the eccentric weight W1 and the rotor case 55, whereby the eccentric weight W1 is held by the rotor case 55.

FIGS. 4 and 5 show a third embodiment of the present invention, which is a small brushless vibration motor of an axial gap type coreless system. The eccentric rotor R2 has a central portion 57.
a rotor 22 to which the shaft 22 is fixed and a plurality of through-holes 57c are provided while leaving the bridging portion 57b from the central portion 57a, and a flat axial gap magnet 68 is fixed inside the rotor yoke 57; A flat eccentric weight W2 plated with pure iron M on a surface of a copper tungsten alloy having a specific gravity of 17 is bonded to a part of 57c. in this case,
Since the flat eccentric weight W2 has a relatively large size, the flat eccentric weight W2 can be made thin enough to be accommodated within the thickness of the rotor case 57, and the eccentric weight does not raise the posture. The rotor case 55 on the opposite side of the eccentric weight W1 is provided with a second notch portion 55c slightly smaller than the first notch portion 55b as a magnetic circuit uniforming means for lightening. It is. Stator S for driving such eccentric rotor R2
2 is a square stator made of heat-resistant and slidable barium titanate whisker-containing polyphenylene sulfide resin outsert molded on a diaphysis 11a cut out of a lead frame made of a thin tinned steel plate (tinplate) in the same manner as described above. Shaft support 1 serving as a bearing in the center of base 11
1a is raised from the diaphysis 11h with the reinforcing tongue 11k included therein, and three-phase six air-core armature coils 33a, 33b ‥‥ 33f are arranged around the shaft support 11a to form a stator S2. Things. A space 11n is provided below the air-core armature coils 33a, 33b and 33f so as to lead out the coil terminals so that the coil ends are not crushed. Part of the diaphysis 11h independently forms a terminal portion 11t except for the common terminal 1k.
h is set to a predetermined shape so that the attraction force by the magnetic force of the axial gap magnet can be controlled. The armature coil is usually formed by connecting opposed armature coils in series, and the terminal is connected to each of the terminals 1t via the exposed portion 1u.

The stator for driving the eccentric rotor as described above may be composed of three-phase six air-core armature coils as described above. The driving circuit member may be stored at the place. In this case, only two positive and negative power supply terminals are required.

The present invention can take various other embodiments without departing from the technical concept and characteristics thereof. Therefore, the above-described embodiments are merely examples and should not be construed as limiting. The technical scope of the present invention is defined by the appended claims, and is not limited by the description.

[0013]

According to the present invention, the eccentric weight has a function of constituting a magnetic circuit to the eccentric weight as described above and is directly fixed to the magnet so that the size is not sacrificed and the amount of vibration is not sacrificed. It is possible to provide a flat small brushless vibration motor using the eccentric weight and the weight. That is, according to the first aspect of the invention, the magnetic circuit of the magnet performs a simple function and can be easily held when directly bonded to the magnet. Claim 2
In the mold invention shown in (1), the present copper-tungsten alloy can be simply processed by surface treatment as it is. According to the third aspect of the present invention, a part can be replaced by iron powder instead of copper. According to the fourth aspect of the present invention, it is possible to provide a motor whose size is not sacrificed even when an eccentric weight is added. According to the fifth aspect of the invention, the weight of the eccentric rotor can be reduced, and the magnetic imbalance can be reduced. According to the invention as set forth in claim 6, the eccentric weight and the magnet can be easily bonded, and the weight of the eccentric rotor can be reduced. According to the seventh aspect of the invention, the eccentric rotor can be reduced in weight and magnetic imbalance can be reduced. In the invention described in claim 8, the magnetic attraction force can be controlled by the arrangement structure of the terminals made of a magnetic material. According to the ninth aspect, chucking can be easily performed, heat resistance can be obtained by the cover, and reflow soldering can be performed.

[Brief description of the drawings]

FIG. 1 is a plan view showing the inside of a small brushless vibration motor of a radial gap type cored type showing a first embodiment as an example of using the eccentric weight of the present invention.

FIG. 2 is a longitudinal sectional view of the motor of FIG.

FIG. 3 is a plan view of the inside of a modified example of the motor of FIG. 1;

FIG. 4 is a longitudinal sectional view of a small brushless vibration motor of an axial gap type coreless system showing a second embodiment as an example of using the eccentric weight of the present invention.

FIG. 5 is a plan view of the inside of the motor of FIG. 4;

[Explanation of symbols]

 1, 11 {stator base 2, 22} axis 3a-3f} armature coil 33a-33f {air core armature coil 4, 44} stator core 4a-4f, 44a-44f {salient pole S, S1, S2} stator R, R1, R2 {eccentric rotor 5, 55} shallow cylindrical rotor case 5b {first notch 5c} second notch 5d {third notch 57} rotor yoke 57a {central part 57b} bridging part 57c} Through hole 6, 66 mm shallow cylindrical magnet 67 ring-shaped axial gap magnet 68 ring-shaped flat magnet C cover W, W1, W2 eccentric weight

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02K 7/065 H02K 7/065 5H622 21/22 21/22 M 29/00 29/00 Z F term (reference) ) 5D107 AA02 AA13 BB08 CC09 DD09 5H019 AA07 AA09 CC02 CC04 CC09 DD01 DD06 5H605 AA07 BB05 BB14 BB19 BB20 CC06 EC08 5H607 BB01 BB07 BB09 BB13 BB14 BB17 BB25 CC01 CC03 DD02 CA08 J08H13K01 PP20 QA03 QA10

Claims (9)

[Claims] An eccentric weight for a small brushless vibration motor, comprising a tungsten alloy having a magnetic material integrated at least partially. 2. The eccentric weight for a small brushless vibration motor according to claim 1, wherein the magnetic body has a surface plated with iron. 3. The eccentric weight for a small brushless vibration motor according to claim 1, wherein the magnetic material is sintered by incorporating iron powder. 4. A first cut-out portion is provided in a rotor case holding the magnet, and at least a part of the eccentric weight is stored in the first cut-out portion and is directly fixed to the magnet. A small brushless vibration motor comprising: an eccentric rotor having a weight reduction means provided on the rotor case on a side opposite to a weight; a stator for driving the eccentric rotor; and a stator base rotatably supporting the eccentric rotor. 5. The rotor according to claim 1, wherein the first notch is provided on a side surface of the rotor case, and the rotor case is provided with a mounting guide for the eccentric weight. 5. An eccentric rotor having a second notch on a side surface.
A small brushless vibration motor according to item 1. 6. The first cut-out portion is provided on a ceiling portion of a rotor case in a fan shape that is expanded when viewed from a plane, and the eccentric weight having substantially the same shape is fitted into the first cut-out portion to form a shaft. An eccentric rotor which is directly adhered to the directional air gap type magnet and provided with a lightening means on the rotor case opposite to the eccentric weight, a stator for driving the eccentric rotor, and a rotatable support for the eccentric rotor. 5. A stator base having terminals arranged sideways.
A small brushless vibration motor according to item 1. 7. The small brushless vibration motor according to claim 6, further comprising an eccentric rotor having a second notch provided in a ceiling portion of the rotor case on the opposite side of the eccentric weight as the lightening means. 8. The stator base is formed of a resin in which a plurality of terminals are independently integrated except for a common terminal, and a skeleton of a magnetic material is integrated, and a part of the magnetic material forms the shaft. 7. The small brushless vibration motor according to claim 6, wherein the small-sized brushless vibration motor is configured to receive a magnetic flux of a direction gap type magnet. 9. The system according to claim 4, wherein at least the stator base is formed in a rectangular shape as viewed from a plane, and each of the terminals is provided so as not to be outward at a corner of the square, and a cover for covering the eccentric rotor is attached. A small brushless vibration motor according to any one of the preceding claims.