JPH0436225Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a brushless motor that can be started smoothly.

[Conventional technology]

When the motor is stopped, the rotor stops at the most magnetically stable position in relation to the stator. Therefore, when the motor is started, the magnetic stability acts as a resistance, and the motor tends not to start smoothly.

Therefore, a DC brushless motor as illustrated in FIG. 9 is conventionally known. In the figure, 1 is a stator core, which integrally has four phase poles 2 and four auxiliary salient poles 3 located between these phase poles 2,
A phase winding 4 is wound around each phase pole 2, respectively.
Further, reference numeral 5 denotes a rotor, and rotor magnets 6 forming the circumference thereof are alternately magnetized to N and S poles, and have a non-excited pole O.

This motor can be made magnetically stable by shifting the center line of the N pole of the rotor magnet 6, for example, with respect to the center line of the phase pole 2 when the motor is stopped, thereby improving startability. .

[Problem that the invention attempts to solve]

However, according to this motor, since the auxiliary salient poles 3 are not electromagnets, the magnetic field centered on the auxiliary salient poles 3 acts to prevent the rotation of the rotor 5 when the phase poles 2 are excited. There is a problem in that rotational unevenness occurs and efficiency tends to deteriorate. At the same time, the slot area is reduced by the provision of the auxiliary salient pole 3,
Moreover, the coil space (therefore, the number of turns of the phase winding 4, which is a factor in determining the magnitude of rotational torque) is also reduced, and the auxiliary salient poles 3 do not interfere with the winding work of the phase winding 4. There was also the issue of becoming. Therefore, in order to secure a slot area that can improve these problems, the stator core had to be made larger.

[Means for solving problems]

In order to solve the above-mentioned problems and to obtain a thinner design or a large rotational torque, the brushless motor of the present invention connects each phase pole of the stator core to the winding part and the tip of this winding part to the left and right. a protrusion formed by at least one approximately T-shaped pole consisting of an ear portion, and extending along the thickness direction at the rotor-facing end of the ear portion located on the rotation direction side of the left and right ear portions; By setting up
The rotor-facing area of one ear is configured to be larger than the rotor-facing area of the other ear.

[Effect]

According to this brushless motor, when the rotor is stopped (when not energized), the rotor is located on the rotation direction side of the ears of each phase pole of the stator core, and the area facing the rotor is large, and therefore the rotor does not dissipate magnetic flux. The center of each pole of the rotor magnet is moved closer to the ear side that is easier to receive, and magnetically stabilized.

In this way, the center of each pole of the rotor magnet is positioned in the direction of rotation with respect to each phase pole of the stator core. In other words, by forming a self-starting daytent based on such positional deviation, it is possible to start the motor without providing an auxiliary salient pole like in the past, thereby preventing a reduction in the slot area and coil space. In addition to improving performance, efficiency can also be improved.

It has already been mentioned that the area facing the rotor can be increased by providing protrusions on the ears located on the rotational direction side of each phase pole, but this is true under the condition that the area facing the rotor is constant. In the case of comparison, since the thickness of the winding portion of the stator core can be made thinner, the thickness of the entire stator around which the windings are wound can be made thinner, thereby realizing a flattened motor. In addition, when comparing under the condition that the thickness of the winding portion of the stator core is constant, the area facing the rotor can be secured larger by the amount of the protruding portion.
This makes it easier to receive magnetic flux, increasing the rotational torque of the rotor.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

Reference numeral 11 in FIG. 2 is a metal motor body with a mounting collar 12, and an output shaft 13 is mounted on a bearing 1 in the center of the motor body.
It is rotatably attached via 4. The output shaft 13 is provided to penetrate the motor body 11 in the thickness direction. A load connecting portion 15 is connected to one end of this output shaft 13, and a load such as a magnetic disk is attached to this connecting portion 15.
Note that 16 in FIG. 2 is a magnet for connecting a load.

A connecting member 17 is fixed to the end of the output shaft 13 opposite to the side on which the load connection part 15 is attached, and a rotor 18 is fixed to this member 17 with a screw 19. Since this embodiment has an outer rotor type, the rotor 18 is formed by attaching a ring-shaped rotor magnet 21 made of a ferrite magnet or the like to the inner peripheral edge of a disc-shaped rotor yoke 20. For example, it is magnetized into four poles. Note that the rotor magnet 21 may be formed of an independent permanent magnet piece for each pole, and the number of poles can of course be determined arbitrarily.

A stator 22 is attached to the motor body 11. The stator 22 includes a stator core 24 which is opposed to the inner circumferential surface of the rotor magnet 21 and has phase poles 23 of the same number as the number of poles of the rotor magnet 21 protruding from the periphery, and a bifilar for each phase pole 23. It is formed by a wound phase winding 25.

Each of the phase poles 23 is composed of at least one substantially T-shaped pole, and the substantially T-shaped pole includes a winding portion A, an ear portion B integrally connected to the left and right sides of the tip of the winding portion A,
It is formed from C. A protruding portion 26 extends along the thickness direction of the stator core 24 at the rotor-opposing end of the ear portion B located on the rotational direction side of the rotor 18 .

Although not necessarily required, in this embodiment, in order to more easily obtain a self-starting daytent, the thickness of the ear portions B and C and the width along the radial direction of the stator core 24 are adjusted to the rotor diameter. 18, the ear part B on the rotation direction side is the other ear part C.
It's made bigger.

The stator core 24 is constructed by stacking a plurality of core plates 27, for example three, as shown in FIG. 3, and one core plate 28 as shown in FIG. 4. Core plate 27
is made of silica steel plate and has four approximately T-shaped pole forming portions 23a forming each phase pole 23. The core plate 28 is also made of dielectric steel and has four substantially L-shaped pole forming portions 23b forming each phase pole 23, and has ear portions thereof. As shown in FIG. 5, the protrusion 26 is integrally bent at the rotor-facing end of component b.

Further, the arrow in FIG. 1 indicates the rotation direction of the rotor 18. Reference numeral 29 in FIG. 1 is a stacking fixing device, such as a caulking pin, for fixing the stacked state of the core plates 27 and 28, and these support the PC board 30 (see FIG. 2). A sensor 31 such as a Hall element and circuit components (not shown) are attached to this PC board 30 for determining the position of the rotor 18 and controlling the excitation of each phase pole 23. In addition, the second
In the figure, 32 is a lead wire whose one end is connected to the PC board 30 and whose other end is led out of the motor body 11.

According to the outer rotor type DC brushless motor having the above structure, when the rotor 18 is stopped (when not energized), the center of each pole of the rotor magnet 21 is located at the protrusion 2 provided at the opposite end of the rotor.
6, the ear portion B has a larger opposing area with the rotor magnet 21 than the ear portion C (therefore, the ear portion B located on the rotational direction side of the rotor 18 is larger than the other ear portion. It receives more magnetic flux and passes through it easily than C.) It is magnetically attracted and stabilized so that it can be brought closer to C.

In the case of this embodiment, since the relationship between the thickness and width of one ear B side and the other ear C is such that ear part B is larger, more Since it becomes easier for the magnetic flux to pass through, the magnetic attraction effect of the rotor 18 described above can be made more reliable.

A stable state resulting from such an action is shown in FIG. In the magnetically most stable relationship between the rotor magnet 21 and the stator 22 shown in FIG. will be located. In FIG. 1, θ indicates the advancing angle of the rotor 18.

Therefore, when the motor is started using a self-starting detent that forms such a positional shift, the phase pole 23 that faces the pole of the rotor magnet 21 and is excited to the same polarity will Smooth starting is possible due to magnetic repulsion and magnetic attraction due to excitation of different polarities of this phase pole 23 and other phase poles 23 adjacent to each other.

In providing the self-starting detent described above, a protruding portion 26 is provided at the rotor-opposing end of the ear portion B, which is located on the rotation direction side of the ear portions B and C of each phase pole 23 of the stator 22. Because it came true,
There is no need to integrally form the auxiliary salient poles on the stator 22 as in the conventional case. Therefore, uneven rotation caused by the auxiliary salient poles is eliminated, the current is reduced, and the efficiency of the motor can be improved accordingly.

Furthermore, by omitting the auxiliary salient poles, the slot area and coil space of the stator 22 can be secured larger than before. Therefore, the winding work is facilitated, and it is also possible to wind more phase windings 25 if necessary, and conversely, if the slot area is the same as the conventional one, the stator 22 and eventually the motor can be made smaller.

Moreover, by providing the protrusion 26 as described above, the end face of the phase pole 23 facing the rotor magnet 21 has a predetermined dimension D in the thickness direction as shown in FIG. The thickness E of the winding portion A of the phase pole 23 can be determined by the predetermined dimension D in the thickness direction on the end surface of the phase pole 23 facing the rotor magnet, by simply determining the stacked thickness of the end surfaces of a large number of core plates shown in FIG. The stator core 23 can be made thinner than the conventional stator core 23 that obtains the same.

Therefore, not only can the weight of the stator core 23 be reduced, but also the winding 25 can be attached to the winding portion A.
When the stator 22 is formed by winding the same amount of the same amount, the thickness of the stator 22 can be reduced.
That is, dimension F in FIG. 7 is the thickness of the stator 22 according to this embodiment, which is thinner than the thickness of the conventional stator shown in dimension G in FIG. 8. Of course, this thinning helps to flatten the entire motor.

Conversely, when comparing the present invention shown in FIG. 7 with the conventional method shown in FIG. 8, if the number of core plates used to form the stator core is the same, the present invention having the protruding portion 26 is better than the conventional one shown in FIG. Since the dimension D in the thickness direction of the opposing end faces can be increased, that is, the area facing the rotor can be ensured to be large, the magnetic flux can be received more easily, and the rotational torque of the rotor 18 can be increased.

Although the above-mentioned embodiment is configured as described above, the present invention can also be implemented in a DC brushless motor of a type in which a rotor is provided inside a stator. Further, in the above embodiment, the stator core is formed by stacking a plurality of types of core plates, but it may be formed by solidifying metal powder or by cutting out silica steel. Further, the present invention can also be implemented in a DC brushless motor having a stator structure in which each phase pole is formed by a plurality of divided poles each forming a substantially T-shape, and the area facing the rotor is increased as the divided poles are closer to the rotation direction. .

In addition, when implementing the present invention, the stator core, phase poles, winding parts,
It goes without saying that the specific structures, shapes, positions, etc. of the ears, protrusions, etc. are not limited to the one embodiment described above, and can be configured and implemented in various ways.

[Effect of idea]

According to the present invention, which has the gist of the configuration described in the above-mentioned utility model registration claims, by providing a protruding portion on the ear portion on the rotation direction side of the ear portions included in each phase pole, the stator core is provided with a protruding portion unlike the conventional one. A self-starting detent can be formed without integrally providing an auxiliary salient pole, and the motor can be started smoothly. Furthermore, by omitting the auxiliary salient poles, uneven rotation can be prevented and efficiency can be improved, and the slot area and coil space of the stator can be increased, and the winding work can also be made easier. Furthermore, the above-mentioned protrusion can make the stator thinner or increase the rotational torque of the rotor.

[Brief explanation of the drawing]

1 to 7 show an embodiment of the present invention,
Figure 1 is a schematic sectional view taken along line I-I in Figure 2;
The figure is a longitudinal side view, Figures 3 and 4 are plan views of different core plates, Figure 5 is a sectional view taken along the line - in Figure 4, Figure 6 is a side view of the stator core, and Figure 7 is a side view of the stator core. It is a sectional view of a phase pole. FIG. 8 is a sectional view of a phase pole according to a comparative example with respect to FIG. 7. FIG. 9 is a schematic sectional view showing a conventional example. 18...Rotor, 23...Phase pole, 24...Stator core, 25...Winding, 26...Protrusion, A...
...Winding part, B, C...Ear part.

Claims (1)

[Scope of utility model registration request] Each phase pole of the stator core is formed by at least one approximately T-shaped pole consisting of a winding portion and ears connected to the left and right of the tip of the winding portion, and
A protrusion extending along the thickness direction is provided at the end facing the rotor of one of the left and right ears located on the rotation direction side, so that the rotor facing area of the one ear is increased from the other ear. A brushless motor characterized in that the area of the ear portion facing the rotor is larger than that of the brushless motor.