JP2596187Y2 - Flat 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 flat motor of a relatively low rotational speed applied to a CD-ROM or a DAT in which the influence of cogging due to a magnetic imbalance is increased by increasing the order and is reduced.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
When fixing the stator yoke 103 in which the coil 102 is disposed on the bearing holding portion 101 of the stator 00, the position facing the magnet 104 is removed as much as possible in order to maintain magnetic uniformity. There is known one fixed by a screw 105.

[0003]

In the prior art, it is difficult to reduce the outer diameter because the bearing holding portion and the stator yoke are connected by removing the portion facing the magnet. In addition, there is a demand for a more compact flat motor, and when a ball bearing is used as a bearing, the diameter of the bearing holding part increases, and the coupling between the bearing holding part and the stator yoke must be performed at a place facing the magnet. It is no longer possible to cope with restrictions on outer diameter dimensions. But,
If a hole is made in the magnet-facing surface of the stator yoke side that constitutes the magnetic circuit and screws are tightened, cogging is induced by the protruding shape of the iron screw head, which has the problem of adversely affecting the rotation accuracy of the motor. I was

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a hole into which a connecting member for connecting a bearing holding portion constituting a stator and a stator yoke is fitted is provided at a position facing the magnet. When the holes are formed, the position of the hole is the central angle in the stator and the electrical angle is substantially (n + 1).
/ 2) π where n is 1 for 4 poles and 1 for 6 poles
Is the field of 3, 12 for 2 and 8 poles, and 4 and 12 for 10 and 10 poles.
In the case of 5 and 14 poles, the position is satisfied. Further, in the case where three fitting holes are formed at positions facing the magnet, the positions of the holes are measured at the central angle in the stator with respect to a predetermined hole, and the electrical angle is measured from the same rotation direction. Approximately (n + ／) π
[Where n is 1 for 4 poles, 2 for 8 poles, 8
In the case of 5, 10 poles, 7, 12 poles, 9, 14
In the case of a pole, the position satisfying 5] is substantially (m + 2/3) π
[Where m is 2 for 4 poles, 3 for 8 poles, 8 for poles
In case 2, 3 in case of 10 poles, 4, 14 in case of 12 poles
In the case of a pole, the position satisfies 8] .

[0005]

The order of the magnetic imbalance can be made uniform and maximized. In general, as the order increases, the absolute value of cogging decreases.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1A is a longitudinal sectional view of the flat plate motor according to the present invention, FIG. 1B is a plan view of a stator having six poles and three coils and three holes, and FIG. With 2 holes
It is a top view of the stator in the case of a part.

The flat motor 1 comprises a rotor 4 having a magnet 2 magnetized in six poles in the thrust direction via a rotor yoke 3 and a stator 6 having three coils 5 arranged face-to-face with the magnet 2. It is composed of Stator 6
Is mounted on a rotating shaft 8 via a bearing 7 and includes a bearing holding portion 9 for holding the bearing 7, a coil 5, and a stator yoke 10 for mounting the coil 5. Holes 12, 13, and 14 for fitting screws 11, which are connecting members, are formed at three places on the stator yoke 10. The holes 12, 1 formed in the stator yoke 10 are also provided in the bearing holding portion 9.
Taps are formed at positions corresponding to 3 and 14, and screws 11 are formed.
Thus, the bearing holding portion 9 and the stator yoke 10 are connected. Reference numeral 15 denotes a Hall element for detecting the magnetic pole of the rotor 4.

First, as shown in FIG. 1B, when the magnet 2 has six poles and three holes, n = 2 and m = 3. The hole 13 of the other holes 13 and 14 with respect to the hole 12 of the stator yoke 10 is (n + ／) π = (2 + ／) π in electrical angle, and the hole 14 is (m + ２) in electrical angle. π = (3 + 2/3) π. The mechanical angles in this case are 140 degrees and 220 degrees, respectively. However,
It is assumed that the hole position does not overlap with the coil 5 and the Hall element 15.

The values of n and m when the number of poles of the magnet 2 is 4 to 14 and the number of holes is 2 and 3 are shown in Table 1.

[Table 1] In Table 1, the value of n with respect to the number of poles of the magnet 2 in the case of two holes is 1 in the case of 4 poles, and 1 in the case of 6 poles.
It is 4 for 2, 10 poles, 5 for 12 poles, and 6 for 14 poles. Further, the value of n with respect to the number of poles of the magnet 2 in the case of three holes is 1 for 4 poles, 2 for 6 poles, 5 for 8 poles, 7 and 12 poles. Is 9 in the case of 14 poles, 5 in the case of 14 poles, and the value of m is 2 in the case of 4 poles, 3 in the case of 6 poles, 2 in the case of 8 poles, and 3 and 12 poles in the case of 10 poles. The number is 4 in the case and 8 in the case of 14 poles.

FIG. 2 is a plan view of the stator 6 in a case where there are six poles and three coils and two holes. Hole 2 of stator yoke 10
0 and the central angle of the hole 21 are n = 2, and the electrical angle is (n + 1).
/ 2) π = (2 + ／) π. The mechanical angle in this case is 150 degrees.

[0011]

As described above, according to the present invention, even if the coupling member for coupling the bearing holding portion and the stator yoke is provided in the magnet-facing surface, the order of the cogging amount generated by the magnetic imbalance is obtained. Is maximized and uniformly generated, so that the cogging amount can be minimized.

[Brief description of the drawings]

FIG. 1A is a longitudinal sectional view of a flat-plate motor according to the present invention, and FIG. 1B is a plan view of a stator having three poles and six holes and three holes.

FIG. 2 is a plan view of a stator in a case where there are two holes with six poles and three coils.

FIG. 3 is a longitudinal sectional view of a flat plate type electric motor according to the prior art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Flat motor, 2 ... Magnet, 4 ... Rotor, 5 ...
Coil, 6 stator, 9 bearing holding part, 10 stator yoke, 11 screw (coupling member), 12, 13, 1
4, 20, 21 ... holes.

Claims (2)

(57) [Scope of request for utility model registration] A rotor provided with a ring-shaped magnet alternately NS- polarized at an equiangular angle in a thrust direction ;
A stator disposed a plurality of coils in the ring-shaped magnet and a surface facing, iron <br/> coupling member for coupling the stator yoke disposed said coil and bearing holder constituting the stator is fitted In a flat-plate type electric motor in which two holes are formed at positions opposed to the ring-shaped magnet ,
The position of the hole in the stator determines the position of the coil in one place.
Electric angle in the circumferential direction as a reference (the ring-shaped magnet
2 [where n is approximately (n + 1/2) π in 2 [pi) in the pole, before
When the multi-pole magnetized number of the ring-shaped magnet is 4 poles, 1;
A flat motor having a position of 2] for 6 poles, 4 for 10 poles, 5 for 12 poles, and 6 for 14 poles. Wherein a rotor is disposed a ring-shaped magnet which is multipolar magnetized in NS alternately at equal angles in the thrust direction, the
A stator disposed a plurality of coils in the ring-shaped magnet and a surface facing, iron <br/> coupling member for coupling the stator yoke disposed said coil and bearing holder constituting the stator is fitted In a flat-plate type electric motor in which three holes are formed at positions opposed to the surface of the ring-shaped magnet ,
The position of the hole in the stator determines the position of the coil in one place.
Electric angle in the circumferential direction as a reference (the ring-shaped magnet
2 [where n is π substantially (n + 1/3) at 2 [pi) in the pole, before
When the multi-pole magnetized number of the ring-shaped magnet is 4 poles, 1;
2 for 6 poles, 5 for 8 poles, 7 for 10 poles,
9 for 12 poles, 5] for 14 poles, and (m
+2/3) π [where m is the number of ring magnets
When the number of poles is 4 poles, it is 2 when it is 6 poles, it is 3 when it is 8 poles, it is 2 when it is 10 poles, it is 3 when it is 12 poles, and it is 4 when it is 14 poles. A flat-plate type electric motor characterized by the following.