JP3476075B2 - Fixed shaft type flat vibration motor without output shaft - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output suitable as a silent information source of a small wireless calling device (pager) or a mobile communication device (portable telephone) or a vibration source of a massager. The present invention relates to a flat type vibration motor having no shaft. 2. Description of the Related Art Conventionally, a flat type vibration motor having no output shaft, especially a flat coreless motor, is disclosed in Japanese Patent Publication No. 7-8 / 1994.
No. 5636 and Japanese Patent Publication No. Hei 8-10972. As shown in FIGS. 6A and 6B, an eccentric rotor R is disposed in a housing H including a case 28 and a bracket 29, and the eccentric rotor R is connected to the case 28 and the bracket 28 via a rotor holder 30 and a shaft 31, as shown in FIG. The structure is such that the bearings are rotatably supported by oil-impregnated bearings 32 and 33 respectively disposed at 29. Since the eccentric rotor R is fixed to the shaft 31, its position is determined by the shaft 31 flush with the housing H. However, in the case of the twin bearing type as described above, the coaxiality of the upper and lower bearings becomes important. In the case of a coin-type flat motor having a thickness of about 3 mm, a case,
10μ coaxiality between the fitting part of the bracket and each bearing
The precision of each component is required, for example, it is necessary to keep the accuracy below m. Such a problem could be solved by using a so-called cantilever type bearing with only one of the bearings.However, as can be judged from the thickness of the motor, a soft oil-impregnated bearing has a low fixing strength and is practical. However, if the fitting portion of the bearing is lengthened, the fitting margin of the rotor holder fitted to the shaft is shortened, and this also poses a practical problem. Further, as a vibration motor of a fixed shaft type in which the shaft does not protrude outside the housing, there is one as disclosed in FIG. 1 of Japanese Patent Publication No. 59-14966. However, such a configuration is difficult to assemble because both ends of the shaft are fixed to the bracket as can be determined from the drawings. In other words, when the rotor 12 is mounted on the bearings 5 and 6 mounted on the brackets 2 and 3 via the shaft support brackets 10 and 11, the stator 7 is in a hindrance. Cannot be embedded. Also, since the bearings 5 and 6 are not attached to the shaft 4 but are unavoidably arranged on the brackets 2 and 3 for the lead wire 9 drawing process, the shafts have to be large in outside diameter. Since the sliding loss of the support brackets 10 and 11 cannot be made as small as that of a shaft, the sliding loss is very large and is not practical. In order to overcome the above-mentioned problems, the applicant of the present invention does not need to rotate the shaft of a vibration motor having no output shaft that utilizes the vibration of the rotor itself, and furthermore, this shaft is fixed at one end only. Focus on what should be done first
No. 814443 has been commercialized as a fixed-shaft flat coreless vibration motor. Such a motor is easy to assemble the rotor, has excellent cost performance, and is popular in the market. By the way, with the miniaturization of portable devices, motors mounted on them are required to be smaller and consume less current. If the diameter of the shaft is 1.2 mm, the shaft must be about 0.6 mm. If it is no longer possible, if such a single shaft support system is used, sufficient consideration must be given to the impact resistance. However, if the fixed portion of the shaft is enlarged, it becomes a bottleneck in thinning. SUMMARY OF THE INVENTION The present invention has been made to overcome the above-mentioned problems, and has sufficient impact resistance in the axial and radial directions while using a thin shaft. An object of the present invention is to provide a flat vibration motor having no output shaft which can be simplified and which is advantageous in cost. [0007] Such a problem can be solved by making it possible to easily assemble the rotor, while supporting the thin shaft at both ends. Specifically, as shown in claim 1, an eccentric rotor having a plurality of armature coils is arranged in a housing consisting of a case and a bracket, and a commutator is arranged on one side of the rotor. A brush is slid on the commutator, and a magnet faces the rotor through a gap, so that a shaft supporting the eccentric rotor does not protrude outward from the housing. Has one end fixed to a part of the housing by press-fitting, the rotor is assembled from the other end of the shaft via one bearing part constituting the rotor, and the other end of the shaft is arranged in the other part of the housing. in the flat type vibration motor without output shaft to form a recess in the casing, the other end of the shaft by disposing made of an insulating material film so as to cover the other end of the shaft to the recess the Fi By entering through the arm, the tip of the shaft is prevented from protruding from the casing, the shaft is prevented from moving in the radial direction, the rotor is eccentric by biasing the recess side And said
A flat vibration motor without an output shaft, wherein the periphery of a bearing hole of the rotor is slidably contacted with the periphery of the recess through a film . In this way, the rotor can be easily assembled, and the shaft can be prevented from moving in the radial direction without increasing the fixed portion at the end of the shaft. It will be able to withstand the impact of such as. The means formed so as to cover the other end of the shaft is provided with a film covering the other end of the shaft at the other part of the housing, and the periphery of the eccentric rotor bearing hole is provided through this film. Since the shaft and the housing are in sliding contact with each other, the shaft and the housing are electrically and mechanically insulated, and at the same time, the slidability of the rotor is maintained. FIG. 1 is a sectional view of a main part of a first embodiment of a flat type vibration motor without an output shaft according to the present invention. FIG. 2 is a plan view of the eccentric rotor of FIG. FIG.
FIG. 6 is a sectional view of a main part of a second embodiment of the motor.
FIG. 4 is a sectional view of a main part of the third embodiment of the motor. FIG. 5 is a sectional view of a main part of a fourth embodiment of the motor. The first embodiment of the present invention is applied to a flat coreless vibration motor as shown in FIG. 1, and a shaft integrally raised at the center of a bracket 1 constituting a part of a housing H. A thin stainless steel shaft 2 is fixed via a holder 1a by press-fitting one end thereof, and a rotor 3 eccentric from an open end is rotatably mounted on the shaft 2. Specifically, the eccentric rotor 3 has three air-core armature coils 3a, 3a, as shown in FIG.
3b and 3c are arranged eccentrically on one side at a pitch of about 60 ° behind the flat plate commutator 5, and are integrally formed with the flat plate commutator 5 provided with the spark quenching element 4a of resin 4 having a low friction coefficient. That is, the resin having a low friction coefficient also serves as one bearing. A ring-shaped magnet 6 made of neodymium is placed on the bracket 1 facing the rotor 3 through a gap, and a pair of brushes 7 are implanted inside the magnet 6 at a sliding contact angle of 90 °. Thus, the flat plate commutator 5 is brought into sliding contact with an appropriate pressing force. On the other hand, a case 8 constituting the other part of the housing
In the center, a tapered through hole 8a functioning as a recess in which the other end of the thin stainless steel shaft 2 is mounted is arranged. The tip of the through hole 8a is smaller than the shaft diameter. That is, the shaft 2 is formed so as to cover at least a part of the other end of the shaft so that the shaft 2 does not protrude outward. The eccentric rotor 3 is connected to the bank 3 around the bearing hole through the polyester film P disposed around the through hole 8a.
The brushes 7 are brought into sliding contact with each other by the pressing force of the pair of brushes 7 through d. For this reason, the eccentric rotor 3 is constantly urged toward the case 8 and is rotatably pressed by the polyester film P. Therefore, there is no danger that the rotor 3 will move toward the case 8 and hit. The rotation can be stably supported without variation.
In addition, since the polyester film itself is also used as a thrust washer, its slidability is good. With this configuration, the rotor 3 prepared in advance is fitted to the bracket 1 also prepared in advance from the open end of the shaft 2, the case 8 is covered, and the outer periphery of the bracket 1 Can be easily assembled. FIG. 3 shows a second embodiment, which is a coin battery type, that is, a bag in which the other end of the shaft 2 of the case 88 is covered so that the case and the bracket can be used as power supply electrodes. The molded recess 88a is formed of a resin 88b having good slidability in order to insulate the case 88 from the case 88, and an insulating means 11a such as polyethylene terephthalate resin is formed on the outer periphery of the bracket 11 by outsert molding. You may make it insulate.
Naturally, the eccentric rotor has the other end of the shaft 2 fitted into the recess 88a, and is rotatably received by the resin 88b having good slidability at a rising portion near the periphery of the recess 88a. In this example, one of the brushes 7 is used in order to use the case and the bracket as power supply electrodes.
7 is soldered directly to the bracket 11, and the other brush 77 passes under the magnet 6 via the flexible plate F and is connected to the inside of the case 88. In order to form a recess for receiving the other end of the shaft 2 so as to provide insulation, slidability and prevent protrusion of the shaft, a third embodiment will be described with reference to FIG. As shown, a through hole T is provided in the case 8 to receive the shaft 2, the through hole T is formed slightly larger than the shaft 2, and the glued polyester film is disposed around the through hole T. P
1, the other end of the shaft 2 may be inserted into the through hole T about halfway. In this case, the periphery of the through hole T of the case 8 is crushed so that the thickness and the gap of the motor itself are not sacrificed by the thickness of the glued polyester film P1, and the glued polyester film P1 is attached here. desirable. This makes it possible to adopt a configuration in which insulation and slidability are maintained without sacrificing thinness. Therefore, it is needless to say that the present invention can be adopted in the coin battery type. FIG. 5 shows a cross section of a main part applied to a shallow cored type flat vibration motor having no output shaft as a fourth embodiment. That is, reference numeral 12 denotes a metal dish-shaped case, and a bracket B is fitted to an opening edge portion thereof. A thin shaft 2 similar to the above is press-fitted and fixed to the bracket B. The shaft 2 has an iron core K formed by bending two eccentric silicon steel plates in the outer periphery in opposite directions to each other. An armature coil 13a is attached to the iron core K via a cover (not shown). An eccentric cored rotor 13 formed by winding is rotatably mounted via one oil-impregnated bearing J fitted inside. A cylindrical commutator C is attached to the rotor 13, and a pair of brushes 77 and 78 are slidably contacted on a sliding surface of the commutator C. The base of the commutator C is mounted on the bracket B via a resin-made brush base 79. Have been. Therefore, the cored rotor 13 decentered here naturally has the iron core K and the armature coil 1.
3a, a cylindrical commutator C and one oil-impregnated bearing J are included. At the top of the dish-shaped case 12, a bag-shaped recess 12a formed by outsert molding a resin having good slidability is provided.
At the time of installation, the other end of the shaft is supported by the recess 12a. For this reason, there is no possibility that the shaft will protrude, and even if the shaft is thin, it can withstand radial movement. In the drawing, reference numeral 14 denotes a cylindrical field magnet disposed on the rotor 13 with a gap therebetween, the magnetic center of which is shifted upward with respect to the center of the rotor 13, whereby the rotor 13 is constantly biased upward. I'm going to let you Therefore, since the rotor 13 is constantly urged in the direction of the recess 12a, there is no possibility that the rotor 13 will slip downward and fall, and the oil-impregnated bearing J portion (around the bearing hole) via the slider 15.
And the position of the rotor 13 is stabilized. Instead of the oil-impregnated bearing J, a resin core cover Ka may be extended inward to function as a resin bearing. In this way, the rotor 13 can be brought into sliding contact with the case ceiling directly via the resin bearing.
As a modified example of the third and fourth embodiments, it is needless to say that the battery type using the case and the bracket as electrodes by removing the lead wires and terminals may be used. Further, one end of the shaft may be fixed to the case side instead of the bracket. Even in this case, since the rotor is at the position where the center of gravity has moved in the radial direction, a large centrifugal force is generated during rotation, and the rotor functions as a vibration motor. As described above, according to the first aspect of the present invention, the rotor can be easily assembled, and the shaft moves in the radial direction without increasing the size of the fixed portion at the end of the shaft. Therefore, even a thin shaft can sufficiently withstand an impact such as a fall. The means formed so as to cover the other end of the shaft is provided with a film covering the other end of the shaft in the other part of the housing, and the periphery of the bearing hole of the eccentric rotor is provided through this film. Since the shaft and the housing are in sliding contact with each other, the shaft and the housing can be electrically and mechanically insulated, and at the same time, the slidability of the rotor can be maintained. Further, if the rotor eccentric by the pressing force of the brush is brought into sliding contact with the housing as the urging means, the urging can be performed only by the spring pressure of the brush, so that the number of parts is increased. Thus, the axial movement of the rotor can be suppressed with a simple structure by effectively utilizing the spring pressure of the brush. Further, when the housing is brought into sliding contact with the housing by the magnetic force of the magnet, the attractive force of the rotor and the magnet can be effectively used.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a main part of a first embodiment of a flat type vibration motor without an output shaft according to the present invention. FIG. 2 is a plan view of the eccentric rotor of FIG. FIG. 3 is a sectional view of a main part of a second embodiment of the motor. FIG. 4 is a sectional view of a main part of a third embodiment of the motor. FIG. 5 is a sectional view of a main part of a fourth embodiment of the motor. FIG. 6 is a sectional view of a main part of a conventional flat vibration motor without an output shaft. [Description of Signs] 1,11 {Bracket 2} Shaft 3} Eccentric coreless rotor 13 {Eccentric cored rotor 4} Resin constituting rotor 5> Commutator 6> Magnets 7, 77, 78, brush 8, 88, case 8a, through hole (recess) 88a, bag-shaped recess 11a, insulating means 12, dish-shaped case 12a, bag-shaped recess P {Polyester film P1} Polyester film T with glue} Through hole (recess)

Continued on the front page (51) Int.Cl. ⁷ Identification code FI H02K 23/54 H02K 23/54 23/58 23/58 Z

Claims (1)

(57) [Claim 1] An eccentric rotor having a plurality of armature coils is arranged in a housing consisting of a case and a bracket, and a commutator is arranged on one side of the rotor. A brush is slid on the commutator, and a magnet faces the rotor via a gap, so that a shaft supporting the eccentric rotor does not protrude outward from the housing. One end of the shaft is fixed to a part of the housing by press-fitting, the rotor is incorporated from the other end of the shaft via one bearing part constituting the rotor, and the other end of the shaft is arranged in the other part of the housing. In a flat type vibration motor without an output shaft , a recess is formed in the case so as to cover the other end of the shaft.
A film made of an insulating material is provided, and the shaft is
By entering the end through the film, while preventing the tip of the shaft from jumping out of the case ,
By preventing the shaft from moving in the radial direction and biasing the eccentric rotor toward the concave side, the film is
A flat vibration motor without an output shaft, wherein the periphery of a bearing hole of the rotor is slidably contacted with the vicinity of the periphery of the recess through the rotor.