JPH0681443B2 - Vibration motor without output shaft - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration motor having no output shaft, which is suitable as a silent notification source for a small wireless calling device (pager) or a vibration source for a massager.

[Prior art]

Conventionally, a vibration motor having no output shaft, especially a flat coreless motor, has been disclosed in Japanese Patent Application Laid-Open No. 63-290153 and Japanese Patent Application No. 63-111868.
Known by the issue. As shown in FIG. 5, each of these has an eccentric rotor R arranged in a housing H composed of a case 28 and a bracket 29. The eccentric rotor R has a rotor holder 30, a shaft 31 and a case 28, The structure is such that the oil-impregnated bearings 32 and 33 respectively arranged on the bracket 29 are rotatably supported. In the figure, S1 and S2 are thrust washers, and S1 is necessary to receive the pressing force of the brushes 12 and 13, but S2 may be omitted.

[Problems to be Solved by the Invention]

However, in the twin bearing type as described above, the coaxiality of the upper and lower bearings becomes important. In a coin type flat motor with a thickness of about 3 mm, in order to prevent the lock and tilt of the rotor, it is necessary to keep the coaxiality of the fitting part of the case and bracket and each bearing below 10 μm. High precision is required. Problems like this
It should be possible to solve it by using a so-called cantilever type bearing with only one of the bearings, but as can be judged from the thickness of the motor, a soft oil-impregnated bearing has poor fixing strength and is not practical, and the bearing fitting If the part is made longer, the fitting margin of the rotor holder fitted to the shaft is shortened, which is also a problem in practical use. In addition, as a shaft-fixed vibration motor that prevents the shaft from protruding outside the housing,
There is one as disclosed in FIG. 1 of 4966. However, in such a configuration, both ends of the shaft are fixed to the brackets as can be seen from the drawings,
It is difficult to install. That is, when the rotor 12 is attached to the bearings 5 and 6 fitted to the brackets 2 and 3 via the shaft support brackets 10 and 11, the stator 7 is an obstacle and cannot be normally incorporated. Further, since the bearings 5 and 6 are not attached to the shaft 4 but are unavoidably arranged on the brackets 2 and 3 due to the lead wire 9 being pulled out, the bearings must be large in outer diameter. The sliding loss of the brackets 10 and 11 cannot be made as small as that of the shaft, so it becomes very large and impractical.

[Object of the Invention]

According to the present invention, in order to overcome each of the problems described above, a vibration motor that does not have an output shaft and uses the vibration of the motor itself does not need to rotate the shaft, and the shaft only needs to be fixed at one end. It was created with a focus on ``, '' it is easy to assemble without keeping the precision of each part more than necessary, and therefore cost effective, and if it is a flat type, it is highly practical even though it is extremely flat. The present invention aims to provide a vibrating motor of a dry cell type, which has a good appearance.

[Means for Solving the Problems]

According to the present invention, an eccentric rotor is arranged in a housing composed of a case and a bracket, a commutator is arranged on the rotor, and a brush is slidably contacted with the commutator.
In a vibration motor without an output shaft, in which a shaft supporting the rotor is prevented from projecting outward from the housing, one end of the shaft is fixedly supported by a part of the housing, and the shaft is eccentric from the open end. Is rotatably mounted by incorporating it through a bearing integrated with this rotor. In the flat type, this bearing is composed of a single oil-impregnated known resin or sintered metal bearing. Well, the case to one power supply electrode,
A means for electrically insulating the case and the bracket may be provided while the bracket serves as the other power supply electrode.

[Action]

As described above, one end of the shaft is fixed and the shaft is rotated toward the bearing, so there is no problem with the coaxiality of the upper and lower bearings, which is the conventional problem. Will be advantageous. Further, since only one end of the shaft is fixed, when adopted in the battery type vibration motor, the means for insulating the case and the bracket can ignore the shaft portion, which simplifies the structure.

First Embodiment A first embodiment of the present invention is applied to a lithium battery type flat coreless vibration motor as shown in FIG. 1, and is applied to a central portion of a case 1 forming a part of a housing. One end of a stainless steel shaft 2 is press-fitted through a shaft holder 1a, a bearing 3 made of resin or sintered metal impregnated with oil from the open end, and a rotor 5 eccentric through a rotor holder 4 Is installed. The eccentric rotor 5 is, as shown in FIG. 2, specifically, two armature coils 6.6 formed by winding a rectangular copper wire at a pitch of about 120 ° and a flat plate with an anchor type weight 7. It is fixed to the commutator 8 by soldering. On the other hand, the bracket 9 which is a part of the housing is outsert-molded with an insulating means 10 made of polyethylene terephthalate resin on the outer periphery thereof, and a neodymium magnet 11 facing the rotor 5 is placed thereon, and an electric angle of 90 ° is provided inside the magnet 11. Then, a pair of brushes 12 and 13 are planted and brought into sliding contact with the flat plate commutator 8 with an appropriate pressing force. Therefore, the rotor 5 is always biased toward the case 1 side and is rotatably pressed by the thrust washer S1, so there is no risk of moving to the bracket 9 side and hitting it. In this embodiment, one of the brushes 12 is directly soldered to the bracket 9 in order to use the case 1 and the bracket 9 as a power feeding electrode, and the other brush 13 is placed under the magnet 11 via the flexible plate 14. And is connected to the inside of the case 1. The rotor holder 4 is not particularly required, and may be directly integrated with resin as in Japanese Patent Application No. Sho 63-111868, or the bearing 3 may be directly integrated with the flat plate commutator 8. Next, the principle of rotation of this motor will be explained with reference to FIG. 3. The magnet 11 is equally magnetized in N and S alternately at a 90 ° opening angle, and two armature coils 6.6 constituting the rotor 5 are formed.
Winding ends of the commutator 8 are connected to the respective segments 8a and 8c of the commutator 8, and end-of-winding terminals are collectively connected to the same segment 8b.
Shorted at b and 15c. Now, when positive and negative voltages are applied to the case and the bracket by a power source such as a battery, first, at the position of "0 °", a current flows in the armature coil 6.6 in the direction of arrow A, and the rotor 5
Rotates according to Fleming's left-hand rule, with torque being generated in the direction of arrow B. The same applies to the position of “60 °” below, and the anti-torque that hinders rotation does not occur at other positions as well. Therefore, as long as power is supplied, the rotation is cyclically switched to continue rotation. Since this rotor has a center of gravity at a position moved from the center in the radial direction, a large centrifugal force is generated during rotation, and the rotor functions as a vibration motor. In addition, although the above-mentioned embodiment shows the one composed of two armature coils, the applicant of the present application filed a Japanese patent application No. Sho 63-111868.
As a matter of course, it may have three armature coils as shown in FIG.

[Second Embodiment] FIG. 4 shows a second embodiment applied to a cylindrical vibration motor without an output shaft.
The cross section of the essential part of the embodiment of That is, 16 is a metal dry battery type cylindrical case, the surface of which is metal-plated with good electrical conductivity, and the opening edge of the case 16 is a bracket that also serves as an insulator made of a thick double-sided printed wiring board. 17 is fitted. The bracket may be a molded product made of polyethylene terephthalate resin instead of the printed wiring board. The case 16 has a recess 16a in the center of the ceiling, and a shaft 18 is press-fitted therein. This shaft
The armatures 22 and 22 are wound around an iron core 21 composed of two poles in which a center of gravity is shifted by cutting out at least a part of one pole among the three poles which are arranged in three equal parts through oil-impregnated bearings 19 and 20. Eccentric rotor 23
Is rotatably attached. A cylindrical commutator C is attached to the rotor R2, and a pair of brushes 24 and 25 are in sliding contact with the sliding surface of the commutator C, and the base of the brush is planted in the bracket 17. One brush 24 is an electrode pattern 17a extended to the outer peripheral end of the bracket 17, and the other brush 25 is the electrode pattern 1a.
It is planted in the other electrode pattern 17c, which is provided even on the outer surface through a through hole 17b insulated from 7a. If the bracket is made of a resin molded product instead of the printed wiring board, a brass plate may be outsert molded instead of the pattern. In the figure, 26 is a cylindrical field magnet that drives the rotor R2, and the magnetic center is displaced upward with respect to the center of the rotor R2, so that the rotor R2 is always biased upward. ing. Reference numeral 27 denotes two or three polyester washers which act as sliders under the urging force of the rotor R2. Therefore, the rotor R2 is always biased in the direction of the slider 27, and there is no risk of slipping downward. With such a configuration, one of the brushes 24 is electrically connected to the case by the electrode pattern 17a when the bracket is assembled to the case 16, so that the entire brush 24 can be a dry-cell type vibration motor. Also in such an embodiment, since the center of gravity of the rotor is moved in the radial direction, a large centrifugal force is generated during rotation and the rotor functions as a vibration motor. In each of the above-described embodiments, the lead wires and terminals are deleted to form the battery type using the case and the bracket as electrodes, but it goes without saying that a normal type having lead wires and terminals may be used. In the flat type, one end of the shaft may be fixed to the bracket side instead of the case.

【The invention's effect】

According to the present invention, since the shaft is fixed as described above, it is not necessary to raise the problem of the core of the case and the bracket, that is, the accuracy of the coaxiality, and the assembly can be easily performed from one side, so that automation is facilitated and the shaft The number of oil-impregnated bearings is more advantageous in terms of cost. Also, by fixing one end of the shaft to the case or bracket, it is not necessary to consider the shaft part as a means for insulating the case and the bracket in the battery type vibration motor.
The structure is simple and the number of parts is reduced, which is advantageous from the working process.

[Brief description of drawings]

FIG. 1 is a sectional view of the essential parts of the first embodiment of the present invention.
FIG. 2 is a plan view of the eccentric rotor in the same embodiment.
FIG. 3 is a development view for explaining the operation. FIG. 4 is a sectional view of the essential parts of the second embodiment. FIG. 5 is a sectional view of the main part of a conventional vibration motor without an output shaft. 1, 16 are cases 2, shafts 5 and 23 are eccentric rotors 9, 17 brackets 10 are insulating means

Claims (3)

[Claims] 1. A eccentric rotor is arranged in a housing composed of a case and a bracket, a commutator is arranged on the rotor, and a brush is slidably contacted with the commutator.
In a vibration motor without an output shaft, in which a shaft supporting the rotor is prevented from projecting outward from the housing, one end of the shaft is fixedly supported by a part of the housing, and the shaft is eccentric from the open end. This is a vibration motor with no output shaft that is rotatably mounted by incorporating this through a bearing integrated with this rotor. 2. The vibration motor without an output shaft according to claim 1, wherein the bearing is a flat type by being constituted by one oil-impregnated bearing. 3. The output shaft according to claim 1, further comprising means for electrically insulating the case from the bracket while the case serves as one of the power feeding electrodes and the bracket serves as the other power feeding electrode. No vibration motor.