JP2005094844A - Mold type eccentric rotor and axial air-gap type coreless vibrating motor comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance impact resistance against falling, etc. by devising an arrangement/structure and a shape of a reinforcing member without sacrificing a thickness or characteristics. <P>SOLUTION: Two air-core armatures 2A and 2B are eccentrically placed on a printed wiring board 1, and integrally molded with resin 5 together with eccentric weight 4. A hanging part 5a is so formed of resin as to turn around the outer periphery of the eccentric weight in a top view, so as to hang on the winding type air-core armature coil. The outer periphery of the eccentric weight is bonded to the hanging part so that a reinforcing member C of non-magnetic metal acts as a framework with one part embedded to hang on the winding type air-core armature coil. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an improvement in impact resistance of a mold type eccentric rotor used for silent call means of a mobile communication device and the like, and relates to a flat and thin axial gap type coreless vibration motor provided with the rotor.

The coreless type eccentric rotor used for the eccentric rotor, especially the thin axial gap type motor used for the silence notification means of mobile communication devices, etc., is a coreless type with an extremely thin thickness of 0.8 mm or less. The one that the armature coil itself is integrally molded with resin so that it can withstand, that is, the one that obtains strength by integrally molding the air-core armature coil with resin together with the printed wiring board is often used.
Moreover, the smaller the eccentric rotor, the more the gap loss must be avoided, and as much as possible, one surface of the armature coil is exposed without being covered with resin. (See Patent Document 1)
However, when pressing with an injection mold so that one surface of the armature coil is exposed, the winding start terminal is crushed by the coil side, causing problems such as short circuit and disconnection.

As a means for preventing problems such as short circuit and disconnection of the coil terminal, the rotor is connected to the metal frame through the terminal in a recess provided below the coil side of the metal frame on which the air-core coil is mounted. There is something. (See Patent Document 2)
However, this product is not molded with resin and has a metal frame, so it cannot be expected to be thin.
Japanese Patent No. 3407803 JP-A-9-322503

  In addition, when such a vibration motor is mounted on a mobile communication device such as a cellular phone, it is required to be as small as possible in size and about 10 mm in diameter, and as a result, the coil itself does not constitute an eccentric rotor. The amount of vibration is small, and an eccentric weight made of tungsten alloy must be used. Also, since the shaft must be 0.6 mm or less, the impact resistance must be fully considered. In particular, when a device on which a motor is mounted is inadvertently dropped, an electronic member such as a motor receives an impact of about 10,000 times its own weight depending on the weight of the device to be mounted depending on the weight of the device to be mounted. There is a fear, and in the case of a small-sized eccentric weight made of a tungsten alloy and integrally molded with a resin, it is important to take measures against damage to the resin due to the weight of the eccentric weight.

  An object of the present invention is to provide an eccentric rotor that reliably takes measures against impact resistance such as dropping without sacrificing thickness and characteristics, and combining such eccentric rotors is extremely useful as a configuration of an axial gap motor. A thin one is realized.

As a basic means for solving the above problem, as in the invention shown in claim 1, the printed wiring board (1, 11) is formed on the first surface side (1a) radially outward at a predetermined opening angle. There are at least two air-core armature coil placement areas (1h, 1n) , and a terminal connection land (1t) formed between the air-core armature coil placement areas is provided, and the second surface side (1b ) , A commutator (1S) composed of a plurality of commutator segments is formed radially outward from the center of rotation, and at least two wire-wound air-core armature coils (2A, 2B) are formed in the air-core armature coil placement area. Are arranged eccentrically, the winding start terminal is connected to the terminal connection land (1r) and the winding end terminal is connected to the terminal connection land (1t), and the eccentric weight (4) made of tungsten alloy is connected to the center of rotation. The above volume Said include rotation center arranged the oil-impregnated bearings to the position of (3) to the printed wiring board with the resin (5) there is a 1.8 specific gravity with the air-core armature coils on the opposite side of the mold the air-core armature coil A reinforcing member made of a non-magnetic metal, which is integrally formed and has a drooping portion (5a) formed of the same resin so as to wrap around the outer peripheral portion of the eccentric weight in plan view and hang on the wound-type air-core armature coil (C) can be achieved by being fixed to the outer peripheral portion of the eccentric weight and being embedded as a diaphysis in the drooping portion so as to be hooked on the wire wound core armature coil.
More specifically, as in the invention shown in claim 2, the printed wiring board has a non-circular shape by removing the main arrangement portion of the eccentric weight, and the winding air-core armature coil has an arrangement opening angle. It is preferable that the reinforcing member is composed of two pieces of 150 to 170 degrees, and at least a part of the reinforcing member is fixed to the eccentric weight or the printed wiring board (11) before resin molding.
Further, as in the invention shown in claim 3, there is an area for placing more than half of each effective conductor portion of the plurality of wound type air-core armature coils as the air-core armature coil placement area, and a part of the outer diameter Is formed linearly near the outside in the radial direction of the inner diameter of the wound air-core armature coil outside this region, and a terminal connection land (1r) is formed at the position of the inner diameter portion of the wound air-core armature coil. It is good to make it.
And in order to make such an eccentric rotor into a vibration motor, as shown in Claim 4, the mold type eccentric rotor (R) of any one of Claims 1-3 and this mold type eccentric rotor are used. A shaft (8) for supporting, a housing (H) having a thickness of 0.2 mm or less for supporting the shaft, a bracket (6) constituting a part of the housing, and an attachment to the bracket A brush base (F) having a total thickness including the adhesive layer of 0.18 mm or less, and an axial gap type magnet (9) disposed in a part of the bracket so as to face the eccentric rotor via a gap; A brush which is arranged on the brush base inside the magnet and slidably contacts the commutator of the eccentric rotor and urges the mold type eccentric rotor toward a case which forms a part of the housing 10) and provided with, derived as a feeding electrode (Fa) in the brush base portion passes through the hole (6b) provided in said bracket so as to cross the part where the magnet is placed the housing side Can be achieved.

According to the first aspect of the present invention, the drooping portion can be configured to bite into the thickness of the magnet to be combined, so that the substantial thickness of the rotor itself does not increase, that is, there is no loss on the magnetic circuit and the reinforcing member is embedded. In addition, since the reinforcing member serves as a skeleton, damage to the resin due to the weight of the eccentric weight can be prevented.
According to the invention of claim 2, since the weight of the eccentric weight is obtained by the thickness of the printed wiring board, the amount of vibration can be increased.
According to the invention of claim 3, the impact resistance is improved and another eccentric rotor is obtained.
According to the fourth aspect of the present invention, a thin shaft-fixed axial gap type coreless vibration motor with improved impact resistance and negligible brush base thickness can be obtained.

  An eccentric rotor for integrally resin-molding an air-core armature coil and an eccentric weight on a printed wiring board, wherein the drooping portion wraps around the outer peripheral portion of the eccentric weight at the outer periphery of the printed wiring board in a plan view. The outer peripheral portion of the eccentric weight is fixed to the winding-type air-core armature coil so that a reinforcing member made of a non-magnetic metal is formed on the hanging portion and becomes a skeleton. It was buried to hang.

Next, drawings of embodiments of the present invention will be described.
FIG. 1 is a plan view of an eccentric rotor of the present invention. (Example 1)
FIG. 2 is a bottom view of the eccentric rotor.
FIG. 3 is a longitudinal sectional view of an axial gap type coreless vibration motor provided with the eccentric rotor of FIG. (Example 2)
FIG. 4 is an assembly explanatory diagram of one member of the eccentric rotor of FIG.
FIG. 5 is a plan view of a modification of the eccentric rotor of FIG. (Example 3)

Next, a first embodiment of the mold type eccentric rotor of the present application will be described with reference to FIGS.
1 is a plan view seen from the first surface side of the printed wiring board, and FIG. 2 is a plan view seen from the second surface side corresponding to the back side of FIG.
The printed wiring board 1 has regions 1h and 1n formed on the first surface side 1a so that more than half of each of the effective conductor portions of the plurality of wound air-core armature coils can be placed at an open angle of about 160 degrees in plan view. And the upper part 1c, 1d is more than half of the inner diameter of the wound air-core armature coil outside the region, and the radius of the inner diameter of the wound air-core armature coil is substantially the same. The first terminal connection land 1r is formed in the inner diameter portion of the straight line having a tangent line around the outer arc, and the second terminal connection land 1t is formed on the straight portion 1e between the regions. It is formed.
On the second surface side 1b of the printed wiring board 1, a commutator 1S composed of a plurality of commutator segments is concentrically formed with the center of rotation, and the surface thereof is gold-plated. Winding-type air-core armature coils 2A and 2B are placed in each region of the first surface, and winding start terminals 2a and 2b are connected to the first terminal connection land 1r, and a winding end terminal is 2 is connected to the terminal connection land 1t, and is integrated with the printed wiring board 1 with the resin 5 so as to cover the outer diameters of the winding type air-core armature coils 2A and 2B.
Here, a jig as shown in FIG. 3 is used as means for connecting the winding start terminals 2a and 2b of the wound air-core armature coils 2A and 2B to the first terminal connection land. That is, the jig J has a flat portion Ja on which the printed wiring board 1 is placed, and portions 1c and 1d of the outer diameter formed by straight lines of the printed wiring board 1 at the air core armature coils 2A and 2B. In order to use this jig J, each of the air-core armature coils 2A, 2B is set up in the recess Jb. The winding start terminals 2a and 2b are soldered to the first terminal connection land 1r, and then each of the air core armature coils 2A and 2B is rotated by 90 degrees with the outer diameter portions 1c and 1d as fulcrums. Then, as shown by an imaginary line, the regions 1h and 1n may be laid and bonded. If the outer diameter of the coil varies considerably, the movable member Jc supported by the retaining pin Jd is slid as necessary to fit the outer shape of the coil before the adhesive hardens. It is also possible to make the placement position constant.
In this way, even an air core armature coil with a small inner diameter does not have to be forced to insert a soldering iron, so it is easy to connect the winding start terminal, and the air core armature coil has an outer diameter even if the size varies. Since the position is constant, the amount of resin that wraps around the outer diameter of the coil during resin molding can be made constant, and the strength is stable.
Thereafter, the winding end terminal is solder-connected to the second terminal connection land 1t, but this portion is separated so as not to overlap the winding type air-core armature coils 2A, 2B. Attaching can be done easily.

The printed wiring board 1 has a non-circular shape in which the wider side on the opposite side of the air-core armature coil is removed through the rotation center in order to generate vibrations in the rotor itself. An eccentric weight 4 made of tungsten alloy having a specific gravity of 15 or more and provided with first and second stepped portions 4a, 4b as axial retaining means is disposed on the portion, and the printed wiring board 1, air core armature coil 2A, The eccentric rotor R is integrated with the resin 5 having a specific gravity of 1.8 or less together with 2B.
The eccentric rotor R is further provided with one sintered oil-impregnated bearing 3 at the center of rotation. The sintered oil-impregnated bearing 3 may be integrally molded with the resin J, or a means for fitting by press-fitting after resin molding may be employed.
A drooping portion 5a is formed on the outer peripheral portion of the resin 5 in order to increase the cross-sectional area of the resin portion as much as possible to increase the strength. The hanging portion 5a is formed so as to overlap from the arc-shaped portion of the eccentric weight 4 to the air-core armature coils 2A and 2B in a plan view.
On the eccentric weight 4, a horseshoe-shaped reinforcing member C is fixed to the outer periphery by means such as spot welding in a plan view. This reinforcing member is made of a springy non-magnetic stainless material in order to obtain rigidity. Both ends of the reinforcing member are hooked so as to partially overlap the air-core armature coils 2A and 2B in plan view. Therefore, when the air-core armature coils 2A, 2B and the eccentric weight 4 are integrally formed of resin, the reinforcing member C is embedded in the hanging portion 5a as a skeleton, so that the eccentric weight and the air-core armature coil Is less likely to break.
In addition, since this drooping part 5a comes to the outer periphery of the magnet combined as shown in below-mentioned FIG. 3, there is no possibility that a magnetic circuit may be sacrificed.
In this way, since the winding start terminal 2a of the air-core armature coils 2A and 2B is accommodated within the inner diameter of the coils, it is protected from the injection mold, so that the problems of disconnection and short circuit can be avoided.
Here, the resin 5 has a low density (specific gravity) so as not to cancel the position of the center of gravity as much as possible, and has a density of 1.8 or less, such as a polybutylene terephthalate resin having good moldability and reproducibility, and elongation. A glass fiber containing about 15% glass fiber is selected in view of the balance of bending strength.
The eccentric weight 4 is selected to have a density (specific gravity) of 17 to 18.4 in consideration of current consumption and centrifugal force in response to a motor size, for example, a diameter of 14 mm to 10 mm.
As shown in FIG. 3, the sintered oil-impregnated bearing 3 has a cylindrical shape and is provided at the center position of the printed wiring board 1, and an eccentric rotor R is rotatably supported on the bracket 7 by a shaft 8 described later. Further, a convex portion 3 a is provided on the outer periphery at the center portion in the axial direction of the sintered oil-impregnated bearing 3. By this convex portion 3a, the sintered oil-impregnated bearing 3 can increase the axial pull-out strength with respect to the eccentric rotor R after molding.
Further, the same effect can be obtained even if the convex portion 3a is intermittently formed not over the entire outer periphery of the cylindrical sintered oil-impregnated bearing 3, and in this way, the mounting strength in the rotating direction is also increased. be able to.

The eccentric rotor R thus configured is used as an axial gap type coreless motor as shown in FIG. That is, the eccentric rotor R is rotatably mounted on the shaft 8 whose base end is press-fitted and fixed to the burring portion 6 a provided at the center of the bracket 6 via the sintered oil-impregnated bearing 3. In a housing H.
The housing H is made of magnetic stainless steel with a thickness of 0.2 mm or less, preferably 0.15 mm to 0.1 mm, so as to be thin and strong. The eccentric rotor R receives the magnetic field of the ring-shaped axial gap type magnet 9 disposed on the bracket 6 through the axial gap. Electric power is received through the commutator S by a pair of brushes 10 and 10 disposed on the flexible brush base F at the inner diameter portion of the magnet. Here, the flexible base F is made of polyester or polyimide film, and a thickness of about 0.18 mm including the glue is selected.
The bracket 6 is provided with a through hole 6b so as to cross a portion where the magnet 9 is placed, and a part of the brush base F is extended in the radial direction, and passes through the through hole 6a. It is derived as a feeding electrode Fa.
Since the thickness of the brush base can be ignored by this through hole, a thin motor can be realized.

FIG. 5 shows a modification of the eccentric rotor, in which the reinforcing member CC is formed in a ring shape so as to cover the entire circumference of the eccentric weight 4 and the printed wiring board 11, and the eccentric rotor R1 is formed by resin molding into a disk shape. Therefore, the same members as those in the previous figure are denoted by the same reference numerals and the description thereof is omitted.
That is, here, the printed wiring board 11 is different from the printed wiring board 1 of FIG. 1 in that the upper portion is an arc portion 11e in plan view, and the portion in which the eccentric weight 4 is stored is deleted and is non-circular. It has not changed. The hanging portion 55a as described above can be formed on the entire circumference by the arc portion 11e so as not to hit the magnet.
Here, the reinforcing member CC is made of a springy white material having a nonmagnetic thickness of about 0.3 mm, is formed in a ring shape in plan view, and is fixed to the outer periphery of the eccentric weight 4 by means such as spot welding. At the same time, it is fixed to the land 11g formed on the arc portion 11e by soldering.
Thereafter, the reinforcing member CC is embedded in the hanging portion 55a when the printed wiring board 11, the air-core armature coils 2A and 2B, and the eccentric weight 4 are integrally formed with the resin 55.
In this way, the reinforcing member CC fixed to the eccentric weight 4 is hooked so as to partially overlap the air-core armature coils 2A and 2B in a plan view, and is also fixed to the land 11g of the printed wiring board. Therefore, the reinforcing member CC becomes a strong skeleton, and even if the weight of the eccentric weight increases, the resin 55 is hardly damaged.

The mold type eccentric rotor according to the present invention can be thinned because the structure is such that the air-core armature coil and the eccentric weight are integrally molded on the printed wiring board as described above, so that the strength can be sufficiently reduced, and particularly the axial gap coreless vibration motor. Therefore, it can be configured to be extremely thin and can be used as an industrially meaningful technical means as a silent notification means for portable devices such as mobile communication devices.
Moreover, although what was formed with the printed wiring board as a commutator was shown, the commutator segment may arrange | position another commutator to this segment with a copper foil.
The number of magnetic poles can be adjusted according to the axial air-core armature coil to be combined even with 6 poles or 4 poles, and the number of coils does not need to be limited to 2; according to the magnetic pole of the magnet to be combined, It can be set to three.

It is a top view of the eccentric rotor of this invention. (Example 1) It is a bottom view of the eccentric rotor of FIG. The axial direction void | hole type coreless vibration motor provided with the same eccentric rotor is shown, and the part of an eccentric rotor is sectional drawing of the AA of FIG. It is assembly explanatory drawing of one member of the eccentric rotor of FIG. It is a top view of the modification of the eccentric rotor of FIG. Example 3

Explanation of symbols

1,11 Printed wiring board
2A, 2B Air-core armature coil 3 Sintered oil-impregnated bearing 4 Eccentric weight 5, 55 Resin 6 Bracket 7 Case H Housing 8 Shaft 9 Magnet 10 Brush F Flexible base
R, R1 Eccentric rotor

Claims (4)

  The printed wiring board is provided with a shaft insertion hole at the center of rotation, and has at least two air-core armature coil mounting areas formed at a predetermined opening angle radially outward through the shaft insertion hole on the first surface side. Furthermore, a terminal connection portion formed between the air-core armature coil placement areas is provided, and a commutator including a plurality of commutator segments is formed around the shaft insertion hole on the second surface side, At least two wound-type air-core armature coils are arranged eccentrically in the air-core armature coil placement area, and an eccentric weight made of tungsten alloy is located in a space on the opposite side of the wound-type air-core armature coil via a rotation center. The air core armature coil is integrated with the printed wiring board with a resin having a specific gravity of 1.8 or less so as to wrap around the outer periphery of the eccentric weight in a plan view so as to be hooked on the wire wound type armature armature coil. Hanging part Formed in the same resin, the wire-wound air-core buried molded eccentric rotor as diaphysis to the suspended portion as applied to the armature coil with a reinforcing member made of a nonmagnetic metal is secured to the outer periphery of the eccentric weight.   The printed wiring board has a non-circular shape in which a main arrangement portion of the eccentric weight is deleted, the winding air-core armature coil has two arrangement opening angles of 150 to 170 degrees, and the reinforcing member is at least The mold type eccentric rotor according to claim 1, wherein a part thereof is fixed to the eccentric weight before resin molding, and a sintered oil-impregnated bearing is disposed in the shaft insertion hole.   The molded eccentric rotor according to claim 1, a shaft that supports the molded eccentric rotor, a housing that supports the shaft, a bracket that constitutes a part of the housing, and a bracket that is attached to the bracket. A brush base, an axial gap type magnet disposed in a part of the bracket so as to face the eccentric rotor via a gap, and a brush base disposed inside the magnet. A brush that slidably contacts the commutator and urges the mold-type eccentric rotor toward a case forming a part of the housing, and a part of the brush base passes below the magnet to the side of the housing. An axial gap type coreless vibration motor derived as a feed electrode.   At least one end of the shaft is fixed to the bracket, an opening of a case constituting a housing is assembled to the bracket, the housing is configured with a thickness of 0.2 mm or less, and the brush base is a flexible substrate. The thickness of the adhesive layer is 0.18 mm or less, and the housing is provided with a through hole in a part of the part where the magnet is arranged, and a part of the brush base is disposed on the side of the housing through the through hole. The axial gap type coreless vibration motor according to claim 3, wherein the motor is led out as a feeding electrode.

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