JP2010004599A - Flat vibration motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flat vibration motor in which a defect of contact, occurring in assembling, between the outer circumferential side of a rotor and the inner face of the top plate portion of a case can be suppressed to improve the yield. <P>SOLUTION: The flat vibration motor inludes: a stator plate 11 obtained by inserting one end of a support shaft 13 into a center hole H<SB>1</SB>for being welded therein; the rotor 20 having an eccentric weight 24 and rotatably supported relative to the support shaft 13 via a slide bearing 21; and a flat cup-shaped case 17 having a top plate portion 17a with the other end of the support shaft 13 entered into a center hole H<SB>2</SB>for being welded therein and having a circumferential wall 17b with its opening sealed with the stator plate 11. The top plate portion 17a has a thin portion T with a circular groove R on the circumferential portion 17b side of the inner face of the top plate portion. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a so-called coin-shaped flat vibration motor configured using a brushless motor or the like.

In the flat vibration motor disclosed in Japanese Patent Laid-Open No. 9-131020, a rotor that is rotatably supported via a slide bearing with respect to a spindle that has one end fixed to a metal stator plate, and the other end of the spindle are fixed. In order to prevent the rotor from flapping due to the clearance of the fitting tolerance between the slide bearing and the support shaft, a magnetic plate attracted by a magnet fixed on the stator plate is used for the rotor. It is provided on the side, so that the slight inclination posture of the rotor with respect to the plane orthogonal to the support shaft can be maintained.
Japanese Patent Laid-Open No. 9-13310 (FIG. 1)

  For assembly, one end of the support shaft is fixed to the stator plate by welding or the like, and the other end of the support shaft is fixed to the top plate portion of the case by welding or the like. The vertical error with respect to the vertical axis and the vertical error with respect to the top plate of the spindle inevitably occur, and in the flat vibration motor, the top plate of the case and the rotor face each other with a small gap. This causes a problem that the outer peripheral corner of the rotor comes into contact with the inner surface of the top plate of the case, causing a reduction in the yield of the flat vibration motor.

  Accordingly, in view of the above problems, an object of the present invention is to provide a flat vibration motor that can suppress the problem that the outer peripheral side of the rotor contacts the inner surface of the top plate portion of the case due to variation in assembly, and can improve the yield. is there.

  The present invention includes a stator plate in which one end of a support shaft is fixed in a first hole, a rotor having an eccentric weight and rotatably supported by a support shaft via a slide bearing, and the other end of the support shaft. A flat vibration motor including a top plate portion fixed in a second hole and a flat cup-shaped case having a peripheral wall portion in which an opening portion is closed with the stator plate, the top plate portion having an inner surface Of these, a thin wall portion having an annular groove is provided on the peripheral wall portion side.

  Even if an error in the verticality of the support shaft relative to the stator plate and an error in the verticality of the support shaft relative to the top plate portion inevitably occur in assembly, the inner surface of the top plate portion has an annular groove on the peripheral wall side. Since the thin-walled portion is formed, as long as the outer peripheral side corner of the rotor is not excessively tilted by the depth of the annular groove, it is possible to suppress problems that come into contact with the inner surface of the thin-walled portion and improve the yield. This partial thinning of the top plate portion can be easily realized by a crushing process when the case is obtained by press molding, so that the cost can be reduced without impairing the flattening. Further, it is not necessary to reduce the weight of the eccentric weight as compared with the case where the outer peripheral side corner portion of the rotor is chamfered, and the vibration force does not need to be reduced.

  The thin portion may have a uniform thickness, or may have a gradient thickness that gradually becomes thinner as it moves outward in the radial direction.

  In addition, even when the outer peripheral corner portion facing the top plate of the rotor has a gradient thickness that gradually becomes thinner in the radial direction, the outer peripheral side of the rotor is in contact with the inner surface of the top plate portion of the case. Can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the flat vibration motor which can suppress the malfunction which the outer peripheral side of a rotor contacts the inner surface of the top-plate part of a case for the depth of an annular groove, and can improve a yield can be provided.

  Next, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 is a cross-sectional view showing a flat vibration motor according to a first embodiment of the present invention. The flat (coin-shaped) vibration motor of this example is a brushless motor including a stator 10 and a rotor 20.

The stator 10 includes a metal (magnetic material) circular stator plate (base plate or bottom plate) 11, a support shaft (fixed shaft) 13 that is welded by fitting one end into the center hole H ₁ of the stator plate 11, and the support shaft. Switching washer including a washer 12 fitted to 13, a power supply flexible substrate 30 that is heat-welded on the top surface of the stator plate 11, and a rotational position detection Hall element mounted on the power supply flexible substrate 30. the circuit 14 and capacitor 15, two disposed on the power supply flexible board 30 and the flat-shaped air-core coil 16 for driving the opening stator plate 11 is fitted in the central hole H ₂ on a support shaft 13 It has a metal shallow cup-shaped case 17 fitted and welded at the other end. The case 17 includes a top plate portion 17a and a peripheral wall portion 17b.

  The rotor 20 is rotatably supported on the support shaft 13 via a plain bearing 21 of the bearing holder portion 23a, and is made of a magnetic material having an annular six-pole permanent magnet 22 facing the flat air core coil 16 on the lower side. The rotor plate 23 and an arc-shaped eccentric weight 24 provided on the outer peripheral side of the rotor plate 23 are provided.

  And the top-plate part 17a of the case 17 of this example is the thin part T of the uniform thickness in which the peripheral wall part 17b side of the inner surface has the annular groove R. FIG. In assembly, both the error in the perpendicularity of the support shaft 13 with respect to the stator plate 11 and the error in the perpendicularity of the support shaft 13 with respect to the top plate portion 17a are inevitably generated. Since the thin portion T having a uniform thickness having the annular groove R is formed on the side of the portion 17b, the corner portion 24a of the eccentric weight 24 is excessively inclined by the depth of the annular groove R, and then the inner surface of the thin portion T is formed. Since it contacts, the malfunction which contacts the inner surface of the top-plate part 17a can be suppressed, and a yield can be improved. The partial thinning of the top plate portion 17a can be realized by a crushing process when the case 17 is press-formed, so that the cost can be reduced without impairing the flattening. Further, it is not necessary to reduce the weight of the eccentric weight 24 as compared with the case where a corner 24a of the eccentric weight 24 described later is chamfered, and the vibration force does not need to be reduced.

  FIG. 2 is a sectional view showing a flat vibration motor according to a second embodiment of the present invention. 2 that are the same as those shown in FIG. 1 are given the same reference numerals, and descriptions thereof are omitted.

  The thin portion T of Example 1 has a uniform thickness, but the thin portion T ′ of this example has a gradient thickness that gradually becomes thinner as it moves outward in the radial direction. Even in the thin portion T ′ formed by the annular groove R ′, the corner portion 24a of the eccentric weight 24 may be inclined until it comes into contact with the inner surface of the thin portion T ′. Therefore, the yield can be improved, and the same as in the first embodiment. There is an effect.

  Further, as shown in FIG. 2, it is possible to make the thickness of the eccentric weight 24 have a gradient thickness that gradually becomes thinner as the corner 24 a side is moved radially outward. In this structure, the weight of the eccentric weight 24 is reduced and the vibration force is reduced. However, when implemented in combination with the configurations of the first and second embodiments, the corner 24a of the eccentric weight 24 contacts the inside of the top plate portion 17a. Can be further suppressed. Although the gradient of the eccentric weight 24 is too steep, since the weight of the eccentric weight 24 is excessively reduced and the vibration force is significantly reduced, the gradient angle is desirably about 2 °.

It is sectional drawing which shows the flat vibration motor which concerns on Example 1 of this invention. It is sectional drawing which shows the flat vibration motor which concerns on Example 2 of this invention.

Explanation of symbols

10 ... Stator 11 ... Stator plate 12 ... Washer 13 ... Support shaft (fixed shaft)
DESCRIPTION OF SYMBOLS 14 ... Switching integrated circuit 15 ... Capacitor 16 ... Flat air-core coil 17 ... Case 17a ... Top plate part 17b ... Peripheral wall part 20 ... Rotor 30 ... Power supply flexible substrate 21 ... Sliding bearing 22 ... Permanent magnet 23 ... Rotor plate 23a ... Bearing holder part 24 ... Eccentric weight 24a ... Corner parts H ₁ and H ₂ ... Central holes R and R '... Annular grooves T and T' ... Thin parts

Claims (5)

A stator plate in which one end of the support shaft is fixed in the first hole, a rotor having an eccentric weight and rotatably supported by a slide bearing with respect to the support shaft, and a second end of the support shaft are connected to the second end. A flat vibration motor including a top plate portion fixed in a hole and a flat cup-shaped case having a peripheral wall portion whose opening is closed by the stator plate,
The flat plate vibration motor is characterized in that the top plate portion has a thin portion having an annular groove on the inner wall side of the top plate portion. 2. The flat vibration motor according to claim 1, wherein the thin portion has a uniform thickness. 2. The flat vibration motor according to claim 1, wherein the thin portion has a gradient thickness that gradually becomes thinner as it moves outward in the radial direction. The flat vibration motor according to any one of claims 1 to 3, wherein the outer peripheral corner portion side of the rotor facing the top plate portion has a gradient thickness that gradually becomes thinner as it moves radially outward. A flat vibration motor characterized by being. A stator plate in which one end of the support shaft is fixed in the first hole, a rotor having an eccentric weight and rotatably supported by a slide bearing with respect to the support shaft, and a second end of the support shaft are connected to the second end. A flat vibration motor including a top plate portion fixed in a hole and a flat cup-shaped case having a peripheral wall portion whose opening is closed by the stator plate,
A flat vibration motor characterized in that the outer peripheral corner portion side of the rotor facing the top plate portion has a gradient thickness that gradually becomes thinner in the radial direction.

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