JP2591628Y2 - Stator structure of 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 brushless motor and a stator structure of a brushless motor having no commutator in sliding contact with the brush.

[0002]

2. Description of the Related Art
This type of brushless motor uses a plurality of N, S
The rotor is formed by arranging the poles alternately in the same circumference so as to form a rotor, while the tips protruding toward these permanent magnets become the magnetic poles facing the permanent magnet, and the coil is wound around the middle part. A stator (stator core) is formed with a plurality of tastes, and the position of the rotor is detected by magnetic detecting means which is disposed opposite to the rotor and magnetically detects the permanent magnet. Switching control of the application of current to the coil wound around the middle part of the tee is performed so that magnetic energy is generated between the permanent magnet and the stator to generate a rotational torque. By the way, in such a brushless motor, when it is an even-numbered one such as two-phase, there is a point where no rotational torque is generated in the positional relationship between the stator and the rotor, that is, there is a position serving as a dead point. When the relationship between the stator and the rotor is symmetrical, the motor stops at the dead point, and the motor does not start. Therefore, conventionally, in order to avoid this, or an auxiliary salient pole for starting the stator, the Eagiyatsupu of between the permanent magnet asymmetrically changing its outer shape with the Teisu leading edge to a non-circular shape Thus , when the motor is stopped, the stator is prevented from being in the dead center state. However, the former has the problem that the auxiliary salient poles protrude separately, which hinders the coil winding work, resulting in poor workability and a heavy stator, and also the latter. for, Eagiyatsupu is inevitably gap is large between the permanent magnets upon an uneven result, not Motori efficiency is lowered, the teeth tip shape for each setting characteristics
There is a problem that a mold having a different shape must be prepared .

[0003]

SUMMARY OF THE INVENTION The present invention has been made in order to provide a stator structure of a brushless motor capable of eliminating these disadvantages in view of the above-mentioned circumstances. A rotor with permanent magnets alternately arranged in the same circumference so as to have different poles, and a tip protruding toward the permanent magnet becomes a magnetic pole facing the permanent magnet, and a coil is wound in the middle part A brushless motor comprising: a stator having a plurality of tastes to be provided; and a magnetic detecting means disposed to face the rotor and magnetically detecting a permanent magnet, wherein the stator has a plate material made of a ferromagnetic metal. When fixing a plurality of laminated plate materials by a rivet that penetrates in the axial direction, the rivet is made of a material having a magnetic permeability different from the magnetic permeability of the plate material. When And the penetration position of the rivets, is characterized in that the relative radial line as the center of symmetry and the stator a Teisu tip section is set at a position shifted in the circumferential direction either.

[0004] In the present invention, with this configuration, the starting problem does not occur while the outer shape of the stator is symmetrical.

[0005]

Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a brushless motor. A rotor 2 constituting the brushless motor 1 includes a rotating shaft 3, a cylindrical yoke 4 provided integrally with the rotating shaft 3, and an inner periphery of the yoke 4. It is constituted by four permanent magnets 5 which are fixedly arranged on the same circumference so that N and S poles are alternately arranged on the surface. On the other hand, the stator 6 rotatably supports the rotary shaft 3 via a bearing 7, but has a substantially T-shape from a boss portion 6 a externally fitted to the bearing 7 and has an intermediate portion. The four teeth 6b around which a coil (stator coil) 8 is wound project radially in the outer radial direction at an angle of 90 degrees. The outer peripheral edge of the tip end portion 6c has a perfect circular shape, and is configured to be closely opposed to the permanent magnet 5 at an equal interval S.

Reference numeral 9 denotes a wiring board provided integrally with the stator 6. The wiring board 9 is disposed opposite to the permanent magnet 5, and is a magnetic sensing element for detecting the magnetism of the permanent magnet 5. Various elements and electric components for controlling the switching of the current application to the coil 8 based on the detection of the magnetic sensing element 10 are installed and wired. Then, it is set so as to generate magnetic energy between the permanent magnet 5 and the tip end portion 6c to generate a rotational torque based on switching control of current application to the coil 8 in accordance with the detection of the magnetic detection element 10. I have.

Now, the stator 6 is formed by laminating a plurality of sheets 11 formed by punching a plate material 11 made of a ferromagnetic metal having a high magnetic permeability such as iron, cobalt or the like into a predetermined shape. As a specific shape, the outer peripheral edge of the tip end portion 6c forms a perfect circle and faces the permanent magnet 5 at an equal interval S, and passes through each taste 6b of the stator 6 to form a center of symmetry. Are configured to be line-symmetric with respect to the center diameter line L. These laminated plate members 11 are integrally fixed by penetrating the rivet 12, but the rivet 12 is made of a low magnetic metal having a low magnetic permeability such as aluminum or chromium. . And the penetration position of the rivet 12
At the tip end portion 6c, the eccentric position is set so as to be deviated in one of the circumferential directions with respect to the center diameter line L. On the other hand, the side on which there is no rivet 12 is set to have a higher magnetic permeability and is magnetically asymmetric.

In the embodiment of the present invention constructed as described above, as described above, the tip end portion 6 of the stator 6
The outer peripheral edge of the c is set in a symmetrical shape with respect to the center diameter line L in a perfect circle state, but the tip end portion 6c is located at a position where the rivets 12 having different magnetic permeability are eccentric from the center line L. , It is magnetically asymmetric. As a result, when the motor is stopped, the rotor 2 does not stop at the position of the dead center where the stator 5 and the rotor 2 do not generate the rotational torque, and does not stop at the position shifted from the dead point state. Stopping the motor does not hinder the start of the motor.

[0009] Thus, despite one not hinder any motor starting, in order that, or provided for starting the auxiliary salient poles as in the prior art, or to the outer peripheral shape of Teisu destination edge in a non-positive-circular shape Therefore, the rivets 12 necessary for integrally fixing the laminated plate members 11 are effectively utilized to be magnetically asymmetrical. As a result, the winding operation of the coil 8 is hindered by the auxiliary salient poles. The air gap S between the tip end portion 6c and the permanent magnet 5 can be made uniform and as narrow as possible.
Efficiency up can be measured . In addition, the outer peripheral shape of the tooth tip edge
The shape should be the same, and only by changing the rivet position
As a result, it is possible to set multiple
With a common mold for punching tastes
Will be able to.

The present invention is not limited to the outer rotor type in which the rotor is outside the stator as in the above-described embodiment, but may be applied to an inner rotor type shown in FIG. It goes without saying that you can do it.

[0011]

[Effects] In summary, since the present invention is constructed as described above, a rivet made of a material having a different magnetic permeability from the stator is provided at the tip of the taste facing the permanent magnet at a position shifted from the center diameter line. Through it, it becomes magnetically asymmetric. As a result, when the motor is stopped, the stator and the rotor do not stop in a dead center relationship where no rotational torque is generated, but stop in a positional relationship deviated from the dead center state. Does not hinder Like this
Although there is no hindrance to motor start-up, in order to do so, there is no need to provide auxiliary start-up salient poles as in the past, or to make the outer peripheral shape of the edge of the taste wire non-circular, without laminating. The tip of the taste is made magnetically asymmetrical by effectively utilizing the rivets necessary for integrally fixing the plate material. As a result, the coil winding work is not disturbed by the auxiliary salient poles, The air gap between the tip of the taste and the permanent magnet can be made uniform and as narrow as possible, so that the efficiency can be improved, and the shape of the tip of the taste is shared while changing the rebate position for various characteristics. Yes, there is no need for each corresponding mold.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view of a brassless motor.

FIG. 2 is a front view of a stator.

FIG. 3 is a front view of a stator showing another example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brushless motor 2 Rotor 5 Permanent magnet 6 Stator 6b Tace 6c Taste tip 8 Coil 10 Magnetic sensing element 11 Plate material 12 Rebet

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) H02K 29/00 H02K 1/18 H02K 21/00

Claims (1)

(57) [Scope of request for utility model registration] 1. A rotor in which a plurality of permanent magnets are alternately arranged on the same circumference so as to have different polarities, and a tip protruding toward the permanent magnet becomes a magnetic pole facing the permanent magnet, and has a middle part. A brushless motor comprising: a stator having a plurality of tastes around which coils are wound around a portion; and a magnetic detection unit disposed opposite to the rotor and magnetically detecting a permanent magnet. It is assumed that a plurality of plate members made of a magnetic metal are laminated and formed. When fixing these laminated plate members by a rivet penetrating in the axial direction, the rivet is different from the magnetic permeability of the plate material. A material having magnetic permeability, and a penetration position of the rivet is set at a position at a tip end portion of the taste and shifted in any circumferential direction with respect to a radial line serving as a center of symmetry of the stator. Brushless mode Stator structure.