JP2006068593A - Vibrating motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent contacting of washers with its shaft, which serves as a noise-generating source during rotation of a motor and a cause of rotation loss of a rotor. <P>SOLUTION: The motor is a brush-less vibrating motor having an eccentric rotor whose rotation is supported by a shaft fixed to a housing. The eccentric rotor consists of an oil-containing bearing having a shaft hole and a cylindrical part, a cylinder part composed of a magnetic plate covering the outer cylindrical surface of the oil-containing bearing, a yoke having a magnet-attaching part extending from the cylinder part in the direction of the outside diameter, a driving magnet attached to the magnet-attaching part, and an eccentric weight attached to the rotor, and the driving magnet opposes a coil arranged in the housing. The end of the cylinder part is protruded from the end face of the bearing in the axial direction so that the contour restricts the motion from the end face in the radial direction. The motor has a washer having a through hole penetrating the shaft and covering the end face of the bearing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a vibration motor used as a silent vibration notification source of a small mobile communication body or a vibration source of a massage device, and more particularly to a brushless vibration motor capable of extending the life.

Conventionally, cylindrical or flat brush type motors have been widely used as silent vibration notification sources for small communication bodies and vibration sources for massage devices.
However, in such a brush type motor, since the brush and the commutator are in sliding contact with each other to supply power to the coil provided on the rotor, the sliding contact portion is used when aiming at higher rotation and higher output of the motor. The brush and commutator were very burdensome, and there was a limit to extending the service life.
In order to further extend the life of the motor, a brushless motor that controls the direction of the current flowing in the coil by a drive circuit and rotationally drives the rotor in accordance with the relationship between the magnetic force generated from the coil and the magnetic force of the magnet provided in the rotor. A vibration motor was developed.
As such a brushless vibration motor, an oil-impregnated bearing is used as a bearing provided on the rotor, and a rotor yoke is fixed to the bearing. (See Patent Document 1)

Japanese Patent No. 3537815

However, in the oil-impregnated bearing, oil retained inside the oil-impregnated bearing may be scattered when the rotor rotates, and the bearing surface needs to be covered to prevent the oil from scattering.
In the configuration of the rotor as shown in the patent document, the bearing side surface is covered with a yoke, but impregnated oil may be scattered from other portions.

  In order to solve the above problems, in a vibration motor having an eccentric rotor that is rotatably supported by a shaft fixed to a housing, the eccentric rotor includes at least an oil-impregnated bearing, a drive magnet, and an eccentric weight. The oil-impregnated bearing has a shaft hole and an end surface perpendicular to the shaft, the rotor has an end protruding in the axial direction from the end surface, and movement in the radial direction is restricted by the end. It is possible to achieve this with a vibration motor characterized by having a through-hole through which the shaft passes and a washer that covers the end face.

  In the vibration motor having an eccentric rotor that is rotatably supported by a shaft fixed to the housing, the eccentric rotor includes an oil-impregnated bearing having a shaft hole through which the shaft is inserted and a cylindrical portion, and an outer cylinder of the oil-impregnated bearing. A cylindrical portion formed of a magnetic plate covering the surface, a yoke having a magnet mounting portion extending continuously in the outer diameter direction with the cylindrical portion, a driving magnet attached to the magnet mounting portion, and attached to the outer peripheral side of the rotor A brushless vibration motor, wherein the driving magnet is opposed to a coil provided in the housing, and one end of the cylindrical portion protrudes in an axial direction from an end surface formed on the bearing. And having an outer shape in which movement in the radial direction is restricted by the one end portion, a through-hole through which the shaft passes, and covering the end surface of the bearing It is possible to achieve a vibration motor having a shear.

As a specific means, an end edge that protrudes in the axial direction from the end face of the bearing and bendable in the axial direction is provided at one end of the cylindrical portion, and the end edge is deformed in a direction in which the shaft is located, What is necessary is just to comprise the vibration motor which regulates the movement of the said washer in the radial direction with the front-end | tip part of the said edge while fixing the said yoke and the said bearing.
Further, there is a problem with a vibration motor in which the difference between the diameter of the circumference formed by the one end and the outer diameter of the washer is smaller than the difference between the diameter of the shaft hole of the bearing and the diameter of the through hole of the washer. Can be achieved.

  If each part is configured as in the present invention, it is possible to prevent the oil from being scattered by the washer formed on the rotor, and further, the movement of the washer in the radial direction is suppressed, so that the rotor rotates on the shaft during rotation. Since it is possible to prevent the washer from coming into contact, it is possible to suppress the occurrence of rotational loss and noise due to friction between the shaft and the washer.

Next, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a longitudinal sectional view of the vibration motor according to the first embodiment.
FIG. 2 (a) is a plan view of the rotor as viewed from the radial direction, and FIG. 2 (b) is an XOY sectional view of FIG. 2 (a).
3 is an enlarged view of a YOZ cross-sectional view of the bearing portion of the vibration motor shown in FIGS. 1 and 2 (a) and 2 (b). (A) is a view before crimping the opening edge 41g. Indicates after caulking.

The axial gap type brushless vibration motor shown in FIG. 1 is a housing formed of a bracket 20 and a case 30, a shaft 21 whose ends are fixed to the case 30 and the bracket 20, and a shaft 21 within the housing. The rotor 40 is freely supported.
The bracket 20 is formed in a disk shape with a plate material such as stainless steel, and a recess 20a for fixing one end of the shaft 21 is formed at the center. One end of the shaft 21 is inserted into the recess 20a and fixed to the bracket 20 by welding, press fitting, or the like.
An FPC board 24 is attached to the inner surface of the housing of the bracket 20. The FPC board 24 is provided with a coil 22 and a drive circuit 23 so as to face the rotor 40, and a holding portion in which a power supply terminal 24 b for supplying power to the coil 22 and the drive circuit 23 is provided on the bracket 20. It is supported by 20b and led out of the housing.

The case 30 is formed of a plate material such as stainless steel in a cup shape, and a recess 30a for holding the other end of the shaft 21 is formed at the center.
The oil-impregnated bearing 43 is formed in a cylindrical shape having a cylindrical large-diameter portion 43r having a large outer diameter and a small-diameter portion 43s having a smaller outer diameter, and a step portion 43a is formed by the large-diameter portion 43r and the small-diameter portion 43s. Yes. The oil-impregnated bearing 43 is supported by the shaft 21 through the shaft hole 43h.
The yoke 41 is concentric with the shaft 21 and has a cylindrical portion 41b formed in a cylinder with substantially the same inner diameter as the large-diameter portion 43r of the oil-impregnated bearing 43, and has an outer diameter continuously from the upper end portion 41a of the cylindrical portion 41b on a plane perpendicular to the shaft 21. The flat portion 41c is formed in the direction, and the extended end portion 41d is provided on the outer peripheral side of the flat portion 41c. The oil-impregnated bearing 43 has a large-diameter portion 43r accommodated in the cylindrical portion 41b.

At the lower end of the cylindrical portion 41 b, an end portion 41 e that supports the stepped portion 43 a of the oil-impregnated bearing 43 in the direction of the shaft 21 is extended toward the center so as to form a surface perpendicular to the shaft 21. The central opening of the end 41e is opened slightly larger than the diameter of the small diameter portion 43s, and the small diameter portion 43s is exposed to the bracket 20 side.
The rotor 40 is always pulled toward the bracket 20 by the magnetic force of the drive magnet 42, and the exposed portion of the oil-impregnated bearing 43 is in contact with the spacer 25 and maintains the position with the bracket 20.
An annular drive magnet 42 magnetized with a predetermined number of poles is attached to the bracket 20 side of the flat surface portion 41c, and an eccentric weight 44 is attached to the extended end portion 41d.
In the oil-impregnated bearing 43, the outer peripheral side of the large-diameter portion 43r is covered with the cylindrical portion 41b, the step portion 43a is supported in the axial direction by the end portion 41e, and the opening edge 41g provided at the end portion 41a of the cylindrical portion 41b. Is fixed to the yoke 41 by deforming the shaft toward the shaft 21 side.

Hereinafter, the configuration will be described in detail with reference to FIGS.
A plurality of openings 41h are formed in the flat surface portion 41c of the yoke 41 along the cylindrical portion 41b. In this embodiment, four openings 41h are formed at intervals of 90 degrees. The opening 41h is substantially rectangular, but the cylindrical portion 41b side is opened so as to form an opening edge 41g along the outer periphery 41f of the cylindrical portion 41b, as shown in FIG. An opening edge 41g as an end portion of the cylindrical portion 41b is formed so as to protrude in the axial direction from the end surface 43b of the oil-impregnated bearing 43 on the case side.
Then, by bending the opening edge 41g in the axial direction, the tip portion presses the large-diameter portion 43r (so-called caulking processing), and the oil-impregnated bearing 43 is fixed to the yoke 41. That is, the large-diameter portion of the oil-impregnated bearing 43 is inserted and fixed by the end portion 41e and the processed opening edge 41g.

  If it fixes in this way, since it crimps using the outer peripheral part of the large diameter part 43r, the shaft hole part 43h of the oil-impregnated bearing 43 will not be affected, but favorable fixation can be performed. The number of the openings 41h may be determined as appropriate depending on the size of the bearing, the thickness of the yoke, and the like.

Next, a washer 45 is attached to the end face 43 b of the oil-impregnated bearing 43 so that the oil impregnated in the oil-impregnated bearing 43 does not scatter. The washer 15 is made of a thin plate material having good slidability, such as metal or resin, and is formed in an annular shape. Its outer diameter is slightly smaller than the inner diameter of the cylindrical portion 11b, and an opening 15a through which the shaft 21 is inserted is formed at the center. Is done. The outer diameter of the washer 45 is set to be slightly smaller than the diameter of the circle formed by the respective front end portions 41i around the shaft hole so as to be positioned at the front end portion 41i of the opening edge 41g after crimping. In the center of the washer 45, an opening 45a larger than the shaft hole 43h is provided as a shaft insertion hole.
At this time, the relationship between the outer diameter of the washer 45, the size of the opening 45a, the diameter of the circle formed by the tip 41i, and the diameter of the shaft hole 43h of the oil-impregnated bearing 43 is as shown in FIG.
That is, as shown in FIG. 3B, the radial clearance (movable range amount b1 + b2) between the washer 45 and the tip 41i is the diameter of the opening 45a of the washer 45 and the shaft hole 43h of the oil-impregnated bearing 43. The difference is smaller than the difference in diameter (corresponding to the clearance between the washer and the shaft a1 + a2).
The washer 45 is attached to the end face 43 b by the surface tension of the oil impregnated in the oil-impregnated bearing 43.

If each part is constituted as described above, the tip 41i as a positioning is formed by the opening edge 41g for caulking and fixing the yoke 41 and the oil-impregnated bearing 43, and the washer 45 is attached to the exposed end face 43b. The end face 43b can be covered to prevent oil from scattering.
Further, by configuring the dimensions of the washer 45 and each component as described above, it is possible to prevent the shaft 21 and the washer 45 from contacting each other while the rotor 40 is rotating, and to prevent generation of abnormal noise and rotation loss. Become.
In addition to the above-described embodiment, the end 41e can be further extended in the axial direction so as to cover the small-diameter portion 43s of the oil-impregnated bearing 43, and the small-diameter portion 43s is made small and within the plate thickness of the yoke 41. Also comes out. Furthermore, it is possible to eliminate the small-diameter portion and to make the oil-impregnated bearing 43 only by the large-diameter portion 43r.
In the present embodiment, the oil-impregnated bearing 43 has a shape in which cylinders having different large-diameter portions 43r and small-diameter portions 43s are stacked, but any shape can be used as long as it has a surface perpendicular to the shaft and a shaft hole. good.

Next, a second embodiment of the present invention will be described with reference to FIG.
FIG. 4 is a longitudinal sectional view of the vibration motor according to the second embodiment. In addition, about the thing of the same structure, an effect | action, and an effect as 1st Embodiment, the code | symbol similar to FIG. 1 thru | or FIG. 3 is attached | subjected and description is abbreviate | omitted.
The rotor 10 includes an oil-impregnated bearing 13 supported by a shaft 21, a yoke 11 formed of a magnetic plate, a driving magnet 12 having a plurality of magnetic poles, and an eccentric weight 14.
The oil-impregnated bearing 13 is formed in a cylindrical shape having an outer diameter having a large diameter portion 13r and a small diameter portion 13s, and a step portion 13a is formed by the large diameter portion 13r and the small diameter portion 13s. The oil-impregnated bearing 13 is supported by the shaft 21 through the shaft hole 13h.

The yoke 11 is concentric with the shaft 21 and has a cylindrical portion 11b formed in substantially the same inner diameter as the large-diameter portion 13r of the oil-impregnated bearing 13. It is formed by an extended end portion 11d provided on the outer peripheral side of the flat surface portion 11c. And the large diameter part 13r is accommodated in the cylindrical part 11b, and the oil-impregnated bearing 13 is fixed by press fit, welding, or the like.
At the lower end of the cylindrical portion 11b, an end portion 11e that supports the step portion 13a of the oil-impregnated bearing 13 in the direction of the shaft 21 is extended toward the center so as to form a surface perpendicular to the shaft 21. The central opening of the end portion 11e is opened slightly larger than the diameter of the small diameter portion 13s, and the small diameter portion 13s is exposed to the bracket 20 side.

The rotor 10 is always pulled toward the bracket 20 by the drive magnet 12, and the exposed portion of the oil-impregnated bearing 13 is in contact with the spacer 25. An annular driving magnet 12 magnetized to a predetermined number of poles is attached to the bracket 20 side of the flat surface portion 11c, and an eccentric weight 14 is attached to the extended end portion 11d.
The axial dimension of the cylindrical portion 11b is slightly larger than that of the large diameter portion 13r. The oil-impregnated bearing 13 has a step portion 13a supported by the end portion 11e, a large-diameter portion 13r covered with the cylindrical portion 11b and fixed to the yoke 11, and the case-side end surface 13b of the oil-impregnated bearing 13 is cylindrical. The portion 11b is slightly lower than the end portion 11n on the case 30 side, and is positioned with a step.

And the washer 15 is attached to the end surface 13b of the oil-impregnated bearing 13 using this level | step difference. The washer 15 is made of a thin plate material having good slidability, such as metal or resin, and is formed in an annular shape. Its outer diameter is slightly smaller than the inner diameter of the cylindrical portion 11b, and an opening 15a through which the shaft 21 is inserted is formed at the center. Is done. The washer 15 is large enough to cover the end face 13b. The washer 15 is attached to the end surface 13 b by the surface tension of the oil impregnated in the oil-impregnated bearing 13.
At this time, the relationship between the outer diameter of the washer 15, the size of the opening 15a, the inner diameter of the cylindrical portion 11b, and the diameter of the shaft hole 13h of the oil-impregnated bearing 13 is the radial clearance between the washer 15 and the inner diameter of the cylindrical portion 11b ( The amount of the movable range) is made smaller than the difference between the diameter of the opening 15a of the washer 15 and the diameter of the shaft hole 43h of the oil-impregnated bearing 43 (corresponding to the clearance between the washer and the shaft).

If each part is configured as described above, the inner diameter side of the cylindrical portion 11b formed in the yoke 11 serves as the positioning of the washer 15, so that the washer 15 can be prevented from moving in the radial direction, and the oil-impregnated bearing 13 is greatly exposed. It is possible to cover the end surface 13b to be prevented, and the impregnated oil can be prevented from scattering.
In addition, by setting the outer diameter of the washer 15 and the inner diameter of the opening 15a as described above, the shaft 21 and the washer 15 are prevented from contacting each other while the rotor 10 is rotating, and abnormal noise and rotation loss are prevented. It becomes possible to prevent.

FIG. 1 is a longitudinal sectional view of a vibration motor according to the first embodiment. FIG. 2 (a) is a plan view of the rotor as viewed from the radial direction, and FIG. 2 (b) is an XOY sectional view of FIG. 2 (a). FIG. 3 is an enlarged view of a YOZ cross-sectional view of the bearing portion of the vibration motor shown in FIGS. 1 and 2A and 2B. FIG. 4 is a longitudinal sectional view of the vibration motor according to the second embodiment.

Explanation of symbols

10, 40 Rotor 11, 41 Yoke 12, 42 Driving magnet 13, 43 Oil-impregnated bearing 15, 45 Washer 20 Bracket 21 Shaft 22 Coil 23 Drive circuit 30 Case

Claims (4)

In a vibration motor having an eccentric rotor rotatably supported by a shaft fixed to a housing,
The eccentric rotor is a brushless vibration motor including at least an oil-impregnated bearing, a drive magnet, and an eccentric weight,
The oil-impregnated bearing has a shaft hole and an end surface perpendicular to the shaft,
The rotor has an end protruding in the axial direction from the end face;
A vibration motor having an outer shape in which movement in a radial direction is restricted by the end portion, a through hole through which the shaft passes, and a washer that covers the end surface. In a vibration motor having an eccentric rotor rotatably supported by a shaft fixed to a housing,
The eccentric rotor includes an oil-impregnated bearing having a shaft hole through which the shaft is inserted and a cylindrical portion, a cylindrical portion formed of a magnetic plate that covers an outer cylindrical surface of the oil-impregnated bearing, and an outer portion that is continuous with the cylindrical portion. It is composed of a yoke having a magnet attachment portion extending in the radial direction, a drive magnet attached to the magnet attachment portion, and an eccentric weight attached to the outer peripheral side of the rotor,
The drive magnet is a brushless vibration motor facing a coil provided in the housing,
Project the end of the cylindrical portion in the axial direction from the end surface of the bearing;
A vibration motor having an outer shape in which movement in a radial direction is restricted by the end portion, a through hole through which the shaft passes, and a washer that covers an end surface of the bearing.   An end edge protruding from the end face of the bearing in the axial direction and bendable in the axial direction is provided at an end of the cylindrical portion, the end edge is deformed in a direction in which the shaft is positioned, and the yoke and the bearing are 3. The vibration motor according to claim 1, wherein the vibration motor is fixed and the radial movement of the washer is restricted by a tip portion of the end edge. 4.   The difference between the diameter of the circumference formed by the end portion and the diameter of the outer diameter of the washer is smaller than the difference between the diameter of the shaft hole of the bearing and the diameter of the through hole of the washer. The vibration motor according to claim 1.

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