JP2010148188A - Eccentric rotor and axial air-gap type coreless vibrating motor equipped with the eccentric rotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an eccentric rotor which improves durability by securing rigidity for holding a bearing which is embedded in a motor while the motor is low in back height, and the axial air-gap type coreless vibrating motor equipped with the rotor. <P>SOLUTION: The eccentric rotor includes: a printed wiring board 1 having a bearing support hole 1a at its center; a plurality of air-core armature coils 2; the bearing 3 which is arranged in the bearing support hole 1a, and joined to the printed wiring board 1 at its external periphery; an eccentric weight W which is arranged so that a main part is not overlapped with the printed wiring board 1; resin 4 integrated with these items; and a commutator 5 arranged on the printed wiring board 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an eccentric rotor and an improvement in an axial air gap type motor provided with the rotor, and is particularly suitable for use in a silent notification means of a mobile communication device. It relates to the thing which secures enough.

  A vibration motor using centrifugal force vibration is generally used as a silence notification means of a mobile communication device, and such a vibration motor has an eccentric shape having a cross-sectional shape like a ginkgo leaf on the output shaft of a normal rotary type cylindrical motor. Some have weights attached. In addition, some axial gap type flat motors generate centrifugal force vibration in the built-in rotor itself. Since the rotor built-in type vibration motor does not require an output shaft, in recent years, a shaft-fixed type in which one bearing is built in the rotor has been awarded. As such a fixed shaft type, in Patent Document 1, a burring hole is provided in a bracket so that the base end of the shaft is press-fitted and fixed, and the other end of the shaft is received on the case side.

  These motors are generally axially slidable to reduce the height, and as a rotor, a commutator is generally formed by printing a plurality of segment pieces on one side of a printed wiring board, and several microns of precious metal It is plated and integrally molded with resin together with one sintered oil-impregnated bearing.

  However, when a motor having a diameter of about 10 mm and a thickness of about 2.5 mm is required, the bearing also becomes a small one having a diameter of about 1.5 mm. A corresponding acceleration of gravity is applied, and a problem arises that the bearing comes off in the axial direction in the rotor.

Japanese Patent No. 3261329

  In order to prevent this axial movement of the bearing, it is only necessary to form an uneven portion on the outer periphery of the bearing so as to bite into the resin. However, the outer diameter is about 1.5 mm and the length is 1.1 mm. If this is done, it is difficult to form the irregularities, and the bearing length is short and the projected area of the bearing is also reduced, resulting in a problem in durability.

  An object of the present invention is to secure a sufficient bearing holding strength built-in in spite of a low-profile motor and to obtain sufficient durability by securing a bearing projection area.

  In order to solve the above-mentioned problem, as shown in claim 1, as a basic configuration, a printed wiring board provided with a shaft support hole at the center, a plurality of air-core armature coils, and a position of the shaft support hole are arranged. A bearing whose outer periphery is joined to the printed wiring board, an eccentric weight arranged so that the main part does not overlap the printed wiring board, a resin in which these are integrated, and a printed wiring board. This can be achieved with a commutator.

  As a specific configuration, as shown in claim 2, it is preferable that a joining pattern is printed and formed on the outer side of the shaft support hole, and a part of the outer periphery of the bearing is joined to the joining pattern by welding.

  Further, as shown in claim 3, it is preferable that the eccentric weight protrudes from the main portion and is joined to the printed wiring board by a tongue piece overlapping the printed wiring board.

  As another specific configuration, as shown in claim 4, the printed wiring board is preferably arranged so as not to overlap with the air-core armature coil.

  Further, as shown in claim 5, the resin preferably covers the terminal of the air-core armature coil as a terminal protection means, and the printed wiring board is formed with a resin insertion hole. .

  In order to make a motor using such an axial gap type rotor, an axial gap type coreless motor using the eccentric rotor according to any one of claims 1 to 5 as shown in claim 6. The axial gap type eccentric rotor is rotatably supported via a shaft by a housing made up of a case and a bracket, and a brush whose tip is in sliding contact with the commutator and a base end of the brush are implanted. This can be achieved by providing a brush base that is partially led out as a power supply terminal to the side of the case through the lower side of the magnet within the thickness of the bracket.

  According to the first and second aspects of the invention, since the bearing is joined to the printed wiring board by welding such as solder, the printed wiring board functions as a skeleton when integrated with the resin. The impact resistance is sufficient without moving out.

  According to a third aspect of the present invention, since the thickness of the eccentric weight is ensured to the full extent of the rotor by the main portion that does not overlap with the printed wiring board, a large amount of eccentricity is obtained, and the printing is performed with a tongue piece thinner than the main portion Since it is welded to the wiring board and covered with resin, sufficient impact strength can be obtained.

  According to the invention of claim 4, since the printed wiring board does not enter the effective magnetic field, the effective magnetic flux density applied to the coil can be increased even with a thin rotor.

  According to the fifth aspect of the present invention, since the end of the air-core armature coil is not crushed by the mold and the flow of the resin during molding can be secured by the resin insertion hole, there is no short mold during molding.

  According to the sixth aspect of the present invention, it is possible to obtain a low-profile motor without sacrificing the thickness while sufficiently securing the built-in bearing holding strength and utilizing the lower part of the magnet when supplying power to the brush.

  Printed wiring board provided with a shaft support hole in the center, a plurality of air-core armature coils, a bearing disposed at the position of the shaft support hole, and an outer periphery joined to the printed wiring board, and a main part of the printed circuit board An eccentric weight arranged so as not to overlap with a wiring board, a resin in which these are integrated, and a commutator arranged on the printed wiring board are provided. FIG. It is sectional drawing of the axial direction air gap type coreless vibration motor provided with the direction air gap type eccentric rotor. 2 is a bottom view of the axial gap eccentric rotor of FIG. 1, FIG. 3 is a plan view of the axial gap eccentric rotor of FIG. 1, and FIG. 4 is an axial gap eccentric rotor according to the second embodiment (modified example). FIG. 5 is a plan view of a commutator used in the axial gap eccentric rotor of FIG. 4, and FIG. 6 is an axial gap coreless in which the axial gap eccentric rotor of FIG. 4 is incorporated. It is sectional drawing of a vibration motor.

  1 to 3, the axial gap type eccentric rotor R according to the first embodiment of the present invention includes a printed wiring board 1 in which a shaft support hole 1a is formed at the center, and a radially outer side of the printed wiring board 1. A plurality of (here, three at an arrangement pitch of 60 °) air-core armature coils 2 arranged so as not to overlap with the printed wiring board 1, the bearing 3 mounted and joined to the shaft support hole 1a, and the printing A plurality of (in this case, six) commutator pieces 5 which are integrated with a resin 4 having a thermal deformation temperature of 250 ° C. or more together with an eccentric way W which is partially soldered to the wiring board 1 and which is formed with a noble metal clad on the surface. It is a thing arranged.

  The bearing 3 mounted in the shaft support hole 1a of the printed wiring board 1 generates a vertical degree by using a jig on the bonding pattern 1b printed and formed around the shaft support hole 1a, and then generates heat around it. It is welded and joined by soldering 1c by laser irradiation that is not easily transmitted. The eccentric weight W is soldered to the printed wiring board 1 by soldering 1d by applying a solder to the tongue piece Wa protruding inward, and also by laser irradiation. Therefore, even if both ends of the bearing 3 are exposed, the injection-molded resin soldered portion is covered, and the pull-out strength is sufficiently secured. The commutator piece 5 is composed of a sliding contact portion 5a clad with a noble metal on the surface and a connection portion 5b bent in the axial direction, and is arranged in six equal portions with a slit groove 4a therebetween. The connecting portion 5b is inserted into a through hole 1e formed in the printed wiring board 1 and soldered on the upper surface.

  Further, the printed wiring board 1 has a part of the outer periphery as viewed from the bottom surface serving as a guide that matches the outer shape of the air-core armature coil 2, and through a through hole 1 e to short the opposing commutator pieces 5. A short-circuit pattern 1f is formed, and terminal connection patterns 1g for soldering the respective winding start terminals a, b and c of the air-core armature coil are printed on the upper surface side and printed at the positions of the recesses 4e. A terminal connection pattern 1h for collectively soldering the terminals d is printed. In the printed wiring board 1 configured as described above, after the ends of the respective air-core electric coils are soldered, the outer periphery of the bearing 3 is welded to the bonding pattern 1b by the soldering 1c as described above, and the eccentric weight W is formed as a tongue piece. It is welded and joined by soldering 1d with Wa, and is integrally formed with the resin 4 so as to be within the thickness of the air-core armature coil. Therefore, since these members are housed in the resin, they function as a diaphysis, and sufficient strength is ensured. In particular, even if the resin on the upper surface of the tongue piece Wa becomes thin, a sufficient resin portion is secured between the printed wiring board and the removal strength is ensured. Here, the bearing 3 is secured in the longitudinal direction so as to protrude from the top and bottom of the rotor as seen from the configuration shown in the drawing, that is, 85% or more of the thickness of the motor, for example, the thickness of the motor is about 2.4 mm. Since the length of 2.1 mm or more is secured, the inclination of the rotor due to the clearance between the shaft and the bearing is reduced, and it is not necessary to take a lot of air gaps. The durability during rotation is good.

  The axial gap type eccentric rotor R is further formed with a part of the resin, which forms a slightly raised portion 4b as a terminal protection means, for example, the coil terminal is hidden, and each winding start terminal a, b of the air-core armature coil. And c are covered with resin so as to pass through the raised portion, and care is taken so as not to be crushed by the mold during injection molding. Further, a drooping portion 4c is formed over the entire outer periphery on the side where the commutator piece 5 is disposed, and the winding end terminals d of the armature coils are collectively passed through the drooping portion 4c and covered with resin. As a result, the terminal protection means is configured, and the function as a strength securing means for retaining the eccentric weight W due to dropping or the like is achieved.

  In order to secure weight, the eccentric weight W needs to be full of the rotor thickness, that is, formed so that the main both surfaces are exposed, and tongue pieces Wa and Wb are integrally formed inside and outside, As the joining means, the tongue pieces Wa are fixed by soldering, and the tongue pieces Wa and Wb and the printed wiring board 1 are covered with the resin 4 to ensure the removal strength. By doing so, a sufficient amount of eccentricity can be obtained by the specific gravity difference and volume ratio between the air-core armature coil 2 and the eccentric weight W.

  The axial gap type eccentric rotor R is further formed with a recess 4e on the upper surface of the printed wiring board 1 so that the connecting portion 5b can be soldered, and the air core electric coil 2 is wound together with the connecting portion 5b. At first, the terminals a, b and c are solder-welded by laser irradiation or the like, and a resin insertion hole 1j is provided in an appropriate space, so that the resin 4 is well wound.

  In order to store the axial gap type eccentric rotor R, the tip of the shaft 7 is first inserted into a recess 9a having a small-diameter through hole at the center of the case 9, and prepared by laser welding from the outside. The The eccentric rotor R is rotatably mounted on the shaft 7 having such a configuration via the oil-impregnated bearing 3 and the thrust washer S, and is slidably contacted with the bracket 6 via the brush base 10 at an opening angle of 90 °. The brush B faces the magnet 8 disposed on the bracket 6 outside the brush B through a gap, and is stored in a bracket 6 as a housing and a case 9. After that, the shaft 7 is assembled by being laser-welded at the outer periphery of the bracket 6 and the opening of the case 9 by fixing the base end to the recess 6 a having a small-diameter through hole in the center of the bracket 6. In the figure, r is a spark erasing print forming resistor that connects adjacent commutator pieces, 4d is a through hole formed by a guide pin used for positioning during injection molding, 4f is a mold gate, and Wc is an injection mold. It is a positioning recess of an eccentric weight provided for positioning.

  Here, the brush B is a 0.05 mm white plate with a noble metal clad on the sliding contact surface, and a base end is soldered and connected to a brush base 10 attached to the bracket. As shown in FIG. 1, the brush base 10 in which the brush B is implanted has a portion 10 a led out to the side of the case 9 through a through hole 6 c formed in the bracket 6 and serves as a power supply terminal.

  In addition, if the thickness of a bracket is about 0.25, you may make it the recess formed by crushing instead of the said through-hole 6c.

  In this way, the thickness of the brush base 10 can be neglected when the power supply terminal is led out to the side of the case through the lower part of the magnet.

  4 to 6, FIG. 4 shows a modification of FIG. 3, and is a winding type in which the effective conductor portion is opened up to about the opening angle of the magnetic pole of the magnet combined (90 ° in this case) to increase the efficiency. Here, the air-core armature coil 22 is composed of two pieces with an arrangement opening angle of about 120 degrees. Here, the printed wiring board 11 is superimposed on these coils by ensuring the efficiency of the coils. Then, the winding start connection pattern 11k is formed, and the winding end batch connection pattern 11h is formed between the coils. It is soldered to 11h to the batch connection pattern. The outer periphery of the sintered oil-impregnated bearing 3 is welded and joined to the joining pattern 11b by soldering, as in the first embodiment. Since the other members are the same as described above, the same reference numerals are given and description thereof is omitted. However, since there are two air-core armature coils, the terminal processing is reduced and each connection pattern can be omitted considerably. The printed wiring board 11 shown in FIG. 5 has a commutator piece 55 formed by printing, and a slidable contact surface is plated with gold of several microns. In the figure, 11m is a reinforcing pattern formed on the printed wiring board, 55d is an air-core armature coil mounting positioning guide provided on the printed wiring board 11, and 55e is the winding start terminal 22a, 22b of the same coil. The recess is designed so as not to be crushed at the time of molding, and is contained within the thickness of the printed wiring board at the time of resin molding to constitute a terminal protection means. Other members having the same function are denoted by the same reference numerals and description thereof is omitted.

  The opening angle of the air-core armature coil 22 is allowed to be about 150 degrees when it is necessary to increase the weight (area in plan view) of the eccentric weight.

  In the above embodiment, the bearing and the eccentric weight are shown as welded and joined to the printed wiring board by soldering for the sake of simplicity. However, since the sintered oil-impregnated bearing is porous, the oil is impregnated to some extent. Since the adhesive force can be maintained, these may be joined by a strong epoxy adhesive or the like.

1 is a cross-sectional view of an axial gap type coreless vibration motor including an axial gap type eccentric rotor according to Embodiment 1. FIG. It is a bottom view of the axial direction air gap type eccentric rotor of FIG. It is a top view of the axial direction air gap type eccentric rotor of FIG. FIG. 10 is a plan view of a modified example of the axial gap type eccentric rotor according to the second embodiment. It is a top view of the commutator used for the axial direction space | gap type eccentric rotor of FIG. FIG. 6 is a cross-sectional view of an axial gap type coreless vibration motor including an axial gap type eccentric rotor according to a second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 Printed wiring board 1a Shaft support hole 1b Joining pattern 1c, 1d Soldering 1e Through hole 1f, 1g, 1h Connection pattern 2, 22 Winding type air-core armature coil 3 Sintered oil-impregnated bearing 4 Resin 4a Slit groove 4b Swelling part 4c hanging part 4e recess 5 commutator piece 5a sliding contact part 5b connecting part 6 bracket 7 shaft 8 magnet 9 case B brush R eccentric rotor W eccentric weight Wa tongue piece Wb tongue piece

Claims (6)

A printed wiring board with a shaft support hole in the center;
A plurality of air-core armature coils;
A bearing which is arranged at the position of the shaft support hole and whose outer periphery is joined to the printed wiring board;
An eccentric weight arranged so that the main part does not overlap the printed wiring board;
A resin in which these are integrated;
An eccentric rotor provided with a commutator disposed on the printed wiring board.   The eccentric rotor according to claim 1, wherein a joining pattern is printed on the outside of the shaft support hole, and a part of the outer periphery of the bearing is joined to the joining pattern by welding.   The eccentric rotor according to claim 1, wherein the eccentric weight protrudes from the main portion and is joined to the printed wiring board by a tongue piece overlapping the printed wiring board.   The eccentric rotor according to claim 1, wherein the printed wiring board is arranged so as not to overlap with the air-core armature coil.   The eccentric rotor according to claim 4, wherein the resin covers a terminal of the air-core armature coil as a terminal protection means, and a resin insertion hole is formed in the printed wiring board.   An axial gap type coreless motor using the eccentric rotor according to any one of claims 1 to 5, wherein the axial gap type eccentric rotor is freely rotatable via a shaft in a housing composed of a case and a bracket. A brush supported at the tip of the commutator and a base end of the brush are planted, and a part of the brush passes below the magnet within the thickness of the bracket and is led out to the side of the case as a power supply terminal. An axial gap type coreless vibration motor provided with a brush base.

Images