JPH07303349A - Small-sized vibrating motor with eccentric armature core - Google Patents

Abstract

PURPOSE:To increase the vibration of a vibrating motor the eccentric weight of which is reduced and the vibration of which is caused by its rotor itself by increasing the moving amount of the center of gravity of the rotor, to prevent the bending of the shaft of the armature core while the core is of a deformed salient-pole type, and to reduce the cogging torque of the motor so that the motor can be started with a low voltage. CONSTITUTION:A small-sized vibrating motor is provided with a field magnet 1 composed of 2n (n is an even number equal to or larger than 2) pieces of magnetic poles alternately magnetized at nearly equal opening angles, a casing 2 which becomes the magnetic path of the magnet 1, an eccentric armature core in which all of a plurality of salient-poles which receive magnetic fluxes from the magnet 1 are biased to one side, a shaft 5 which supports the armature core, an armature coil wound around the armature core, a commutator composed of a plurality of pieces of commutator segments connected to the terminals of the armature coil, and a blush which is brought into contact and slid on the commutator. The motor is also provided with a notch 3e which reaches the shaft 5 on the opposite side of the shaft supporting section 3d of the armature core.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small vibration motor used as a silent call means of a pager (product name pager), and more particularly to a small vibration motor provided with an eccentric armature core that does not require an eccentric weight. .

[0002]

2. Description of the Related Art Conventionally, as a silent call means such as a pager, an eccentric weight W made of a tungsten alloy is arranged on an output shaft S of a cylindrical coreless DC motor M as shown in FIG. It is known that vibration is generated by utilizing the difference in force.

However, in the above-mentioned conventional type in which the eccentric weight W is added to the output shaft S, there is a design restriction such that the turning space of the eccentric weight W must be taken into consideration on the equipment side such as a pager. However, since an expensive tungsten alloy is used, there is a problem in cost.

Therefore, the applicant of the present invention has previously proposed a cylindrical coreless type vibration motor in which the output shaft is eliminated and the built-in rotor itself is eccentric.
155).

Since the motor does not have an output shaft or an eccentric weight, it is not restricted by design, is easy to use, and has no danger at the time of turning. Since it is a cylindrical coreless winding type, the problem of increased processing man-hours is included.

In order to vibrate the rotor itself in the iron core type instead of the cylindrical coreless winding type, the applicant of the present invention has previously proposed one of the three salient pole type iron cores as shown in Japanese Patent Application No. 2-294482. The one with the pole removed is proposed.

However, the two salient pole type iron core type as described above is suitable for a motor having a relatively large output such as a massager, but the cogging torque becomes large and the starting voltage is considerably high. It is not suitable for portable devices that use low voltage such as pagers.

As shown in FIG. 5, teeth of the salient poles are divided into substantially equal parts, and winding arm portions are formed into non-uniform parts, as a structure for preventing the cogging torque and for increasing the starting voltage. , A means of moving the center of gravity from the center as a whole is also conceivable.

[0009]

Unfortunately, in the structure having the structure for preventing the cogging torque as described above, the center of gravity moves only slightly, so that the difference in centrifugal force during rotation is small and the amount of vibration generated to the outside. Less is. If it is attempted to cover this small amount of vibration with high rotation, the vibration frequency becomes high, giving an unpleasant sensation to the human body, and it is necessary to incorporate an auxiliary eccentric weight.

Moreover, since the salient poles are unequal,
If the shaft is pressed into the center hole of the iron core as it is in order to make the armature core elongated in the longitudinal direction, the pressure applied to the shaft increases as the core thickness increases, and the shaft bends easily. In particular, in recent ultra-fine cylindrical motors, the shaft diameter has to be 0.8 mm or less, so this problem is greatly highlighted. In order to prevent the bending of the shaft, there is a means of gradually changing the mutual positions of the salient poles of the core to disperse the stress, but this cannot be done unless the salient poles are of equal division type.

[0011]

It is a first object of the present invention to eliminate the eccentric weight so that vibration can be obtained only by the armature iron core, and in particular, a structure for increasing the moving amount of the center of gravity is provided. To provide.

A second object of the present invention is to prevent the shaft from bending even though the deformed salient pole core is used, that is, without changing the mutual positions of the salient poles.

A third object of the present invention is to reduce the cogging torque and, therefore, to enable a sufficient starting at a low voltage.

A fourth object of the present invention is to firmly integrate the shaft and the eccentric armature iron core, including the winding protection portion.

[0015]

[Means for Solving the Problems] The basic problem is claim 1
As in the invention shown in FIG. 2, a field magnet composed of 2n (n is an even number of 2 or more) magnetic poles magnetized in N and S alternately at substantially equal opening angles, and a casing serving as a magnetic path of the field magnet. An eccentric armature core in which all of a plurality of salient poles that receive the magnetic flux of the field magnet are biased to one side, a shaft that supports the eccentric armature core, and an armature wound around the armature core. A commutator comprising a coil, a plurality of commutator pieces to which terminals of the armature coil are connected, and a brush slidably contacting the commutator, wherein the shaft support portion of the eccentric armature core is provided. This can be achieved by providing a notch reaching the shaft on the side opposite to the center of gravity.

Another object can be achieved by setting the opening angle of the cutout portion to be smaller than the shaft diameter and fixing the shaft to the shaft support portion by press fitting as in the invention described in claim 2.

Another problem is that the eccentric armature core is made to communicate with the notch as in the invention according to claim 3, and is fixed to the shaft integrally by a resin cover having winding protection portions formed at both ends. Can be achieved.

[0018]

According to the above-mentioned basic object achieving means, since the salient poles are all biased to one side and the notch reaching the axis is provided on the side opposite to the center of gravity, the amount of movement of the center of gravity becomes large. Moreover, since the field magnet has four or more poles, the cogging torque is reduced,
Low voltage startup is possible. The notch allows stress to escape at the time of press fitting, so the shaft does not bend.

According to the above-mentioned means for achieving another object, the eccentric armature iron core is not likely to be off the shaft even if it has a notch.

According to the other means for achieving the above object, the resin easily flows through the notch, so that the eccentric armature core can be integrally resin-molded including the winding protection portions at both ends.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of an embodiment of the present invention will be described below with reference to the embodiments shown in the drawings. FIG. 1 is a horizontal cross-sectional view of a main part of a small vibration motor showing the features of the present invention, and FIG. 2 is a vertical cross-sectional view thereof. In the figure, reference numeral 1 denotes a ring-shaped field magnet made of a rare earth plastic, which is alternately magnetized into four poles N and S.
Reference numeral 2 is a casing made of tin-plated steel plate that holds the field magnet 1 and serves as a magnetic path. 3 is an eccentric armature iron core showing the characteristics of the present application, in which three salient poles on one side are deleted from the salient poles divided into six equal parts, and the remaining three salient poles 3a, 3b and 3c are used to form the eccentric armature iron core. I am configuring.

A notch 3e reaching the shaft 5 is provided in the shaft supporting portion 3d (that is, on the side opposite to the center of gravity) on the opposite side of the three salient poles 3a, 3b and 3c. The width of the notch 3e is made slightly smaller than the shaft so that the eccentric armature core 3 does not come off from the shaft 5 due to centrifugal force or impact. The shaft 5 is attached to the shaft hole 3e by press fitting.

Reference numeral 40 denotes a resin cover which communicates with the cutout 3e and has protective portions 40a and 40b formed at both ends thereof, and is integrated with the shaft 5 including the eccentric armature core 3.

Windings 4a, 4b and 4c of each phase of the armature coil 4 are wound around the three salient poles 3a, 3b and 3c via a resin cover 40. The shaft 5 on which the armature cores are laminated and supported is bearing 2a on the casing 2 so that one end does not project outward and the other end on a bracket 6 fitted in the opening of the casing 2. , 6a are rotatably supported.

Reference numeral 7 denotes a plate type commutator, as shown in FIG. 3, which is divided into six equal commutator pieces 7a, 7b, 7c, 7d, 7
e and 7f between opposing commutator segments 7a-7d, 7
Electrode patterns 8a, 8b and 8c which short-circuit b-7e and 7c-7f are printed.

Reference numeral 9 denotes a pair of positive and negative brushes whose base ends are implanted in the bracket 6 via the terminal 10.
As shown in FIG. 3, the tip of the field magnet 1 is slidably contacted with the commutator 7 at an opening angle (90 ° in this case) of the width of the field magnet 1.

Next, the operation of the rotation principle of the embodiment of the present invention will be described with reference to FIG. The armature coil of FIG. 3 is a star connection system. Now, the positive and negative brush pieces 9a, 9b of the brush 9
When a DC voltage is applied to the armature coil by a required power source (not shown), the armature coil winding 4 is first placed at the position (0 °) of the rotor including the armature coil, the iron core and the commutator.
b and 4c flow in the direction of the arrow, the salient poles 3b and 3c are magnetized to N and S, respectively, and the salient pole 3b is attracted to the S1 pole of the field magnet and repelled by the N1 pole, and is directed in the direction of the arrow A. Torque is generated. Since the salient pole 3c is magnetized to the S pole, the salient pole 3c is attracted to the N2 pole of the field magnet and repelled by the S1 pole, so that torque is also generated in the direction of arrow A.

When the rotation advances to the position of (60 °), torque is similarly generated in the direction of arrow A to rotate, but no anti-torque that hinders the rotation is generated at other positions. Therefore, as long as the power is supplied, it will switch to cyclic and continue rotation.

Although not particularly shown, a delta connection armature coil may be used. Needless to say, the shape and width of the teeth of each salient pole are set to be the ones that are considered to be the best in terms of design.

In the above embodiment, the number of salient poles is three, and the number of magnetic poles of the field magnet is four. However, the number of poles is not limited to this, and the balance with the number of processing steps is not limited. It is also possible to increase the number of poles on the top as required.

Further, in the above embodiment, the resin cover 40 integrated with the cutouts 3e communicating with each other is shown. However, if the core is insulated from the winding, only the core is coated. May be deleted.

Further, the notch 3d has a width smaller than the shaft diameter, but if the notch 3d is integrated by the resin cover 40, it extends into the shaft support portion 33d in a fan shape as shown in FIG. The cutout 33e may be opened. In this case, there is an advantage that a larger amount of movement of the center of gravity can be obtained.

[0033]

As described above, in the small vibration motor according to the present invention, all the salient poles of the armature core are biased to one side, and the notch reaching the shaft is provided on the side opposite to the center of gravity. Is large, vibration with large amplitude is obtained, and since the field magnet is composed of four or more poles, there are advantages that the cogging torque is relatively small and the starting voltage does not increase. Since the stress is dispersed by the notches 3e and 33e without changing the mutual positions of the salient poles, the shaft 5 is not bent. In addition, since the expensive eccentric weight made of copper-tungsten alloy is not used, it is advantageous in terms of cost, and the pager device side is not required to consider the turning space of the eccentric weight, resulting in excellent usability.

[Brief description of drawings]

FIG. 1 is a transverse cross-sectional view of a main part of an embodiment of a small vibration motor including an eccentric armature iron core of the present invention.

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

FIG. 3 is a diagram illustrating a principle of rotation of the motor.

FIG. 4 is a cross-sectional view of a main part of another embodiment of the motor of the present invention.

FIG. 5 is a perspective view of a conventional small vibration motor.

FIG. 6 is a cross-sectional view of a main part of a small vibration motor including a conventional eccentric armature iron core.

[Explanation of symbols]

 1 field magnet 2 casing 2a bearing 3 armature iron core 3a salient pole 3b salient pole 3c salient pole 3d shaft support 33d shaft support 3e notch 33e notch 4 armature coil 5 shaft 6 bracket 6a bearing 7 plate type commutator 9 Brush 10 Terminal 40 Cover

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Arai 236, Hinode Town, Isesaki City, Gunma Prefecture Tokyo Parts Industry Co., Ltd.

Claims (3)

[Claims] 1. A field magnet composed of 2n (n is an even number of 2 or more) magnetic poles magnetized alternately at N and S at substantially equal opening angles, a casing serving as a magnetic path of the field magnet, and An eccentric armature iron core in which all of the plurality of salient poles that receive the magnetic flux of the field magnet are biased to one side, a shaft that supports the eccentric armature iron core, and an armature coil wound around the armature iron core. Comprising a commutator composed of a plurality of commutator pieces to which terminals of the armature coil are connected, and a brush slidingly contacting the commutator, the anti-center of gravity of the shaft bearing portion of the eccentric armature core. A small vibration motor having an eccentric armature iron core, characterized in that a notch reaching the shaft is provided on the side. 2. The small vibration motor with an eccentric armature iron core according to claim 1, wherein an opening angle of the cutout portion is smaller than a shaft diameter, and the shaft is fixed to the shaft support portion by press fitting. 3. The eccentric armature iron core according to claim 1, wherein the eccentric armature iron core is integrally fixed to the shaft by a resin cover having cutouts communicating with each other and winding protection portions formed at both ends. Small vibration motor equipped.