JP2572761Y2 - Rotating yoke type flat brushless motor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary yoke type flat brushless motor suitable for use in portable audio equipment and the like.

[0002]

2. Description of the Related Art A rotary yoke type flat brushless motor conventionally mounted on a headphone stereo player or the like has a basic structure as shown in FIG. 2, that is, a plurality of armature coils are formed by a printed wiring technique. A thin stator 1, a magnet case 2 a on which a ring-shaped field magnet 2 is mounted on one side of the stator 1, and a rotating yoke 3 on the other side of the stator 1 with a gap therebetween.
Are fixed to the rotor holder 4 which is loosely fitted in the through hole 1a provided substantially at the center of the rotor R to constitute the rotor R. A shaft 5 for supporting the rotor R, and the shaft 5 are rotatably supported via bearings 6 and 7 and a metal holder 8 for supporting the bearings 6 and 7, and the stator 1
A bracket 9 for holding the outer peripheral portion of
Reference numeral a denotes a stator holder which forms a part of the bracket 9 and is integrally formed with a rising portion of the bracket 9. In the drawing, reference numeral 10 denotes a receiving plate arranged on the metal holder 8, which pivotally supports the base end of the shaft 5, and reference numeral 4a denotes a step portion for attracting and holding the magnet case 2a and the rotating yoke 3 by the magnetic force of the magnet 2. .

[0003]

[Problems to be Solved by the Invention] Portable audio equipment such as a headphone stereo player is often used at the time of walking or the like, and in such a case, a considerable impact is applied to the set, and the leakage magnetic flux of the field magnet is applied. The rotor R may be lifted upward in the figure against the urging force of the rotor, and the upper surface of the field magnet 2 may contact the stator 1 to generate abnormal noise. If the rotor R comes into contact during rotation, the surface magnet of the field magnet has a rough surface, resulting in a considerable noise.

As a countermeasure against this, if the leakage magnetic flux is intentionally increased to increase the urging force, friction loss of the pivot receiver and eddy current loss of the bracket increase, resulting in a drawback that current consumption increases.

[0005] This invention solves the problem by preventing the entire upper surface of the field magnet from coming into contact with the stator at the time of an impact. Even when an impact is applied at the time of rotation, the field magnet is brought into contact with a small-area nonmetallic member. Accordingly, it is an object of the present invention to provide a rotary yoke type flat brushless motor in which no large noise is generated.

[0006]

Means for Solving the Problems] This invention has a plurality of conductive
A field exposed through a gap to a stator composed of armature rolls
A rotor having a magnetic magnet, the rotor being
It is possible to move in the direction to narrow the gap with the stator
In the opposite direction due to the leakage flux of the field magnet
By biasing, the shaft arranged at the center of the rotor
Rotating yaw with base end pivotally supported on stator base
Before facing the stator
A ring-shaped non-metallic part is located at the approximate center of the surface of the field magnet.
Material to form a step on the surface of this field magnet
It is .

[0007]

In this manner, the field magnet floats up against the biasing force due to the leakage magnetic flux of the field magnet at the time of impact, and even if the field magnet contacts the stator in the figure, the thin nonmetallic member at the center hits the stator. No noise is generated.

[0008]

EXAMPLES While describing the structure of the embodiment of the invention in FIG. 1, similar to FIG. 2 is a conventional example, a plurality of armature co
A thin stator 1 formed by printing wiring technology;
A ring-shaped field magnet 2 is mounted on one side of the stator 1.
The rotating yoke 3 is placed on the other side of the magnet case 2a.
Are arranged through the air gaps, respectively, and are almost at the center of the stator 1.
Each of the rotor holders 4 loosely fitted into the through holes 1a provided
The rotor R is fixed. And this law
Shaft R for supporting the shaft R, and the shaft 5 with bearings 6, 7 and
Via a metal holder 8 that supports the bearings 6 and 7
The rotor R is rotatably supported, and the rotor R
It can move in the narrowing direction and leaks the field magnet 2.
While being urged in the opposite direction by the magnetic flux,
From the bracket 9 holding the outer peripheral portion of the stator 1
9a is a part of the bracket 9.
In the stator holder part,
The body is molded. In the figure, reference numeral 10 denotes a metal holder 8
The pivot plate supports the base end of the shaft 5
4a is a magnet for the magnet case 2a and the rotating yoke 3.
This is a step portion that is attracted and held by the magnetic force of the net 2 . 2 is different from FIG. 2 in that a non-metal member 11 made of a polyester or polyimide film to which an acrylic adhesive is applied is attached to the center of the upper surface of the field magnet 2 as the rotor R, and the surface of the field magnet 2 To form a step
And there .

The film with an acrylic pressure-sensitive adhesive is selected to have a total thickness of 5 mm to 10 mm.
And the width of the ring is preferably as narrow as possible, but is determined in consideration of the adhesive strength.

[0010]

[Effect of the Invention] Since the present invention is constructed as described above, even if the field magnet is lifted in the drawing due to an impact greater than the attraction force due to the leakage magnetic flux of the field magnet, the entire surface (particularly, the outer peripheral portion is not affected). ) Since it does not hit the stator, the noise does not become large, and since the film is non-metallic, it has the effect of not causing unpleasant noise.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a main part of a rotary yoke type flat brushless motor of the present invention.

FIG. 2 is a conventional drawing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator 2 Field magnet 3 Rotating yoke 11 Ring-shaped nonmetallic member

Claims (1)

(57) [Scope of request for utility model registration] 1. A stage comprising a plurality of armature coils.
With a field magnet facing the data through the air gap
The rotor has a narrow gap with the stator.
In the direction of the magnetic field
Urged in the opposite direction by the leakage flux of
The base end of the shaft arranged in the center of the rotor is used as the stator base
Rotating yoke type flat brushless motor with pivot support
The surface of the field magnet facing the stator
A ring-shaped non-metallic member is placed approximately in the center of the
Rotating yoke type flat brushless motor with a step formed on the surface of the net .