JP3707027B2 - Optimized structure of micro flat vibration motor - Google Patents

Description

[0001]
[Industrial application field] In the present invention, when two coreless coils are equally arranged on an electric rotor within a range of 180 degrees, the half-moon shaped rotor has a heavy eccentric load. Generates strong vibration. Micro flat vibration motors are used in mobile phones, pagers, massage machines, signal receivers for the visually impaired, watches, and toys, as you all know.
[0002]
[Prior Art] Normally, a flat vibration motor has a structure in which three coreless coils and a magnet magnet have four poles. The number of commutators is 6 and can be restarted at any time. The above-described three-coil flat vibration motor becomes a vibration motor if one coil is reduced. However, the arrangement range of the remaining two coils exceeds 180 degrees, and the eccentric weight of the rotor becomes insufficient. In some cases, a micro flat vibration motor composed of a flat field magnet having six magnetic poles alternately and N, S and a commutator having nine commutator pieces by placing two coreless coils in an eccentric half-moon shape. There is also.
[0003]
[Problems to be solved by the invention]
The magnetic flux lines in the magnetic path space of the 4-pole or 6-pole N and S alternately magnetized field magnets flow in the horizontal direction at the magnetic field boundary. There is almost no generation of the rotor rotating electromagnetic force on the radial lead wire that entered (Fig. 2). When a coil energized with direct current enters an area where the magnetic flux lines are perpendicular to the plane of the field magnet, the rotor rotating electromagnetic force is generated and output as a motor power source. I can do it. Therefore, whether or not the number of magnetic field poles is optimized is a problem. This significantly affects the energy conversion efficiency of the motor.
[0004]
In the structure of the commutator, the number of commutator pieces is six or nine, or simply speaking, the more the number of the insulating grooves increases, the more friction of the brush becomes when rotating. As the frictional energy loss increases, the efficiency of the motor naturally becomes worse. Therefore, it is necessary to confirm the optimization of the number of commutator pieces. When the brush is passed to the insulating groove of the commutator piece, the power of the coil is turned off and on, so even if some sparks are generated, the brush wears quickly. At the same time, the energization status of the coil, that is, the output status of the motor is also affected. Electromagnetic noise is also generated when the power is turned off and on. Various problems have been pointed out, such as poor contact conduction between the brush and segment, thermal deformation, and increased barrier force passing through the insulating groove. In particular, when the brush direction and the rotor rotation direction do not match, the above-mentioned problem becomes significant. In fact, when tested, the opposite brush sliding surface is completely worn, and the forward brush wears slightly. This is a direct factor for the service life of the motor. The problem of drive torque ripple due to rotor position must also be considered. The problems of motor electrical restart performance and start-up torque ripple are electromagnetic balance problems. The simplest motor that satisfies the above conditions is of course the optimization choice. The development of high-performance motors with the simplest structure and electromagnetic balance for further product miniaturization is an important issue.
[0005]
Conventional oil-impregnated bearings have a problem of lubricating oil popping out by centrifugal force due to high-speed rotation of the rotor. After all, the inside of the motor is dirty. One issue is the use of bearings that do not use oil. One important issue is how to fix the shaft to the case easily and reliably.
[0006]
[Means for Solving the Problems] An N, S dipole planar magnetic field magnet is used. The area having the magnetic flux lines distributed perpendicular to the magnet plane required to generate the rotor rotational torque is the effective magnetic field area. The choice that maximizes the area is the simplest field structure with only two N and S magnetic poles (FIG. 1). As a result of maximizing the entire circumference driving effective magnetic field area, the electromagnetic driving torque works during the rotor rotation, and the time becomes longer. The conversion rate from electrical energy to mechanical energy is also improved. The electromagnetic performance of permanent magnets can be maximized. The magnetizing accuracy is high when magnetizing the magnet, and the magnetizing yoke can be manufactured with only two poles. In particular, the advantages of minimizing the number of magnetic fields can be clearly seen for ultra-small magnets.
[0007]
In the present invention, the basic structure of the vibration motor is a system of “two coils, two magnetic poles, and three commutator pieces” (FIG. 3). The fact that the electromagnetic balance can be obtained will be described with reference to FIG. As shown in Aiming for Intuitive Effects (Fig. 4), two conductors in the four conductors are combined with the radial conductors a1, a2 and b1, b2 that can generate the effective torque of the drive coil at any position of the rotor. Always enter the effective magnetic field area. In other words, the source of the motor rotation driving electromagnetic force is always secured from the two conductors of the rotor coreless coil. In particular, since the density of the vertical magnetic flux lines in the center of the effective magnetic field area is higher than the density in the peripheral part, there is a difference in the driving electromagnetic force received by the conductors a1 and a2 or b1 and b2 of the coil. Rotation drive torque. The drive torque ripple value is minimized. The result of detailed analysis shows that the electromagnetic field number of the magnet is more than 4 or 6 or more even if the source of rotational driving electromagnetic force of other micro-balanced motors with electromagnetic balance is supplied from the same two wires. The range of the area will also increase.
[0008]
The result of optimizing the number of commutator pieces is three. The function of the commutator can be sufficiently exhibited with only three insulating grooves. The number of commutator pieces, that is, the number of insulating grooves can be reduced from 6 or 9 to 2 to 3 times, so that when the rotor rotates, the blocking force passing through the groove between the brush and the commutator, noise, poor conduction, thermal deformation, and spark generation Damage can be largely reduced. In addition, the life of the brush is extended by using a brush structure that matches the rotor rotation direction. Since the connection between the commutator piece and the opposite side of the printer board is performed through a through hole, if the number of commutator pieces is reduced, the number of through holes is also reduced, and the manufacturing cost can be reduced.
[0009]
The minimum number of coils having the ability to restart the motor at any time is two. In the case of a vibration motor, the result of equally arranging the two coreless coils in the 180 degree range of the rotor maximizes the eccentric weight of the half-moon shaped rotor. Since the relationship between the eccentric weight and the rotor centrifugal force is directly proportional, it is directly linked to the vibration strength of the motor. Compared with the three-coil system, the two-coil method enables the manufacture of smaller motors with smaller dimensions.
[0010]
Use dry lubricated sliding bearings. It is possible to optimize the quality, life and cost, such as anti-friction alloy materials and surface physical anti-friction treatment technology. The fixing method of the rotor rotation support fixed shaft is press-fitted into a specially shaped lower case (FIG. 5). There is a round base protruding in the center of the lower case, and there is a punched hole in the center of the round base. Because the hole entrance is chamfered in an arc when pressing, it is easy to set the shaft pin. In the final stage of the press-fitting operation, the metal remaining in the lower case is collected around the hard shaft tip, and a stopper ring-like structure of the shaft is formed. It is a firm fixing method that can withstand vibration by combining the positioning of the upper case center hole.
[0011]
[Embodiment of the Invention] The motor shown in FIG. After wiring the coil 6 on the printed circuit board 8 having two coils printed with the commutator, the coil 6 is set together with the bearing 5 to perform a resin molding operation. The shaft 4 is press-fitted into the lower case 12. The brush 9 is set on the fusible wiring board 13 and soldered, and then bonded and fixed to the lower case 12. Then, the magnet magnet 7 is bonded and fixed to the lower case 12. After optimizing the height of the brush and the clearance of the bearing, the rotor 2 (resin frame), the upper and lower washers 3 and 10 as thrust bearings are inserted and assembled together with the upper case 1.
[0012]
【Example】
As a result of structural optimization, the micro flat vibration motor of “2 coils, 2 magnetic poles, 3 commutator pieces, forward brush” can make a smaller motor. First, looking at the winding work of the coreless coil, the aligned windings of coil a and coil b as shown in (Fig. 3) are similar in shape to the winding cross section of the winding jig. It will be easy to do. Until now, the minimum outer diameter of micro flat vibration motors is close to 10Φ, making rotor design and manufacturing very difficult. In short, it is difficult to arrange the three coils equally on the half-moon-shaped rotor base that is too small in terms of process capability. In the special case of a single coil, the arrangement base is sufficient, but the cross-sectional shape of the coil core is flat, making alignment winding difficult. The two-coil proposal provided here opens the way for rotor design and manufacture of micro flat vibration motors with an outer diameter of 10Φ or less. Two coreless coils can be equally arranged on the half-moon shaped rotor base. It is important that the width of the segment insulation groove and the field groove of the commutator are narrower and more accurate. Since the motor basic structure is the simplest, high precision can be obtained by the principle of precision engineering.
[0013]
[Effects of the Invention] The simplest basic structure was obtained as a result of optimizing the design of each component constituting the motor in the micro flat vibration motor. There are advantages in terms of energy saving, low noise, strong vibration, smaller size, excellent startup performance, long life, stable output, quality, yield rate, and cost reduction.
[Brief description of the drawings]
FIG. 1 is a distribution map of magnetic flux lines of 2, 4, and 6 magnetic pole field magnets.
FIG. 2 is a plan view showing that a coreless coil carrying a direct current is placed in a magnetic field to generate a rotating electromagnetic force.
FIG. 3 is a basic structure and connection plan view of a “2-coil, 2-pole, 3-commutator piece, forward brush” micro flat vibration motor according to the present invention.
FIG. 4 is an intuitional explanatory diagram of the state of all-round rotation torque ripple of a “2-coil, 2-pole, 3-commutator piece” type micro flat vibration motor.
FIG. 5 is a cross-sectional view illustrating a method for fixing a shaft to a lower case.
FIG. 6 is a cross-sectional view of a basic structure of an embodiment of a “2-coil, 2-pole, 3-commutator piece, forward brush” micro flat vibration motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Upper case 2 Resin frame 3 Upper thrust bearing washer 4 Shaft 5 Bearing made of anti-friction alloy or surface anti-friction physical modification 6 Coreless armature coil 2 7 N, S bipolar field magnet permanent magnet 8 Coil wiring printed board 9 Forward Brush 10 Oriented in the Same Direction as the Rotor Rotation Direction 10 Lower Thrust Bearing Washer 11 Commutator Copper Foil Piece 12 Formed on Printed Circuit Board Special Case Lower Case 13 Brush Base Flexible Board

Claims (1)

  DC DC power supply micro flat vibration motor with the following structural features: A rotary electric motor rotor is a half-moon 180 degree range, a vibration motor in which two coreless coils are equally divided; the entire circumference of the commutator The three commutator pieces are arranged at an appropriate angle, and are bonded and fixed to a lower case having a special shape by using a permanent magnet magnet magnetized with N and S dipole planes as a stator. Two brushes coinciding with the rotation direction of the electric rotor are symmetrical with respect to the rotation center.

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