JPS62104465A - Brushless flattened motor - Google Patents

Abstract

PURPOSE:To always stop a device at a re-starting position, by providing an auxiliary yoke on a torque-generating contribution section opposite to the rotor magnet side of driving coils, and by providing the auxiliary yoke, with a salient section protruded to the internal side surface of the driving coils. CONSTITUTION:On a torque-generating contribution section opposite to the rotor magnet 5 side of driving coils 8, an auxiliary yoke 10 made of a soft magnetic member is set. The auxiliary yoke 10 is provided with a salient section 11 protruded to the internal side surface of the driving coils 8. When current fed to the driving coils 8 is interrupted to stop rotational state, then the magnetic poles of a rotor magnet 5 closest to the salient section 11 are attracted by the salient section 11 of the auxiliary yoke 10. Because of said attracting force, the motor stops at a relative position where the center of the rotational direction width and that of the magnetic pole of the rotor magnet 5 do not coincide with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a brushless flat motor, and more particularly to a brushless flat motor that can be driven by a control switching circuit using a Hall element, a Hall IC, or the like.

BACKGROUND ART BACKGROUND ART BACKGROUND ART BACKGROUND ART Conventional brushless flat motors, especially low-cost brushless flat motors, are usually of a two-phase drive type. With this kind of branless polarized i17 motor (J
1. The spacing between adjacent rotor magnets and the spacing in the rotor magnet rotation direction of the torque generation contributing portion of the drive coil are configured to be almost the same.

(c) Problems to be solved by the invention In the conventional two-phase drive type brushless flat motor, the spacing between adjacent rotor magnets and the spacing in the rotational direction of the portion of the drive coil that contributes to torque generation are almost the same. Therefore, during the rotation fQ of the rotor magnet I, at the mutual position of the rotor magnet and the drive coil where the center of the width of the drive coil in the rotor magnet rotation direction and the center of the magnetic pole of the rotor magnet coincide, the current is applied to the drive coil. Even if a current magnetic field is generated, the force generated by the action of the drive coil's TU current magnetic field and the rotor magnet's magnetic field acts in a direction perpendicular to the rotating surface of the rotor magnet, and no torque is generated on the rotor. . Therefore, if the motor stops at such a position, restarting it after stopping cannot be done by simply supplying current to the drive coil; it is necessary to release the positional relationship between the drive coil and rotor magnet as described above. Various methods have been used in the past, but these have had problems such as complicated positioning mechanisms and insufficient position determination.

Additionally, in general, during normal rotation, current is always supplied to only one of the drive coils, and the other drive coil is supplied in close proximity to the center of the magnetic pole of the rotor magnet and the center of the width of the drive coil in the rotational direction of the rotor magnet. Switch the current supply to the coil. Therefore, if the motor rotation stops intentionally or due to some external factor at a mutual position where the magnetic pole center of the rotor magnet and the width center of the drive coil in the rotational direction of the rotor magnet coincide, current is being supplied. In the drive coil, due to the current magnetic field of the drive coil and the magnetic field of the rotor magnet, the rotor magnet and the drive coil are attracted to each other in a direction perpendicular to the rotating surface of the rotor magnet, and no torque is generated. At the same time, in the drive coil that is not currently being supplied with current, the center of the magnetic pole of the rotor magnet and the center of the width of the auxiliary yoke in the rotational direction of the rotor magnet are aligned, and the magnetic force of the rotor magnet causes the drive coil to be placed below the drive coil. The auxiliary yoke is attracted in the direction perpendicular to the rotating surface of the rotor magnet, and no torque is generated. Therefore, the mutual position f of the rotor magnet and drive coil is
, 77, fixed the problem that it could not be restarted unless the relationship was canceled.

In order to solve the above-mentioned problems, an auxiliary yoke made of a soft magnetic member is installed in the part of the drive coil that contributes to torque generation, opposite to the rotor magnet side. In addition, the auxiliary yoke is provided with a protrusion that protrudes from the inner surface of the drive coil.

(e) Operation When the brushless flat motor stops from rotating and the current supply to the drive coil is stopped, the drive coil loses the current magnetic field. In other words, the interaction due to the magnetic force between the rotor magnet and the drive coil disappears, and the protrusion of the auxiliary yoke provided on the part of the drive coil that contributes to torque generation, which is opposite to the rotor magnet side, is connected to the rotor closest to the protrusion. Attracts the magnetic poles of the magnet.

Due to this attractive force, when the rotational force due to the inertia of the rotor becomes smaller than the attractive force of the magnetic poles of the rotor magnet, the center of the magnetic pole of the rotor magnet almost coincides with the protrusion, so the center of the width of the drive coil in the rotational direction of the rotor magnet , they stop in a mutual positional relationship that does not coincide with the center of the magnetic pole of the rotor magnet. That is, it always stops at a position where it can be started.

In addition, if the rotation of the motor is stopped intentionally or due to some external factor at a mutual position where the magnetic pole center of the rotor magnet and the width center of the drive coil in the rotational direction of the rotor magnet coincide, the current supply of current is disabled. In the case of a drive coil that is not in use, the protrusion of the auxiliary yoke provided below is attracted to the magnetic pole of the nearest rotor magnet, and current is currently being supplied to the other drive coil, so the current magnetic field is The interaction between the current magnetic field formed by the drive coil and the protrusion of the auxiliary yoke provided on the inner surface of the drive coil and the magnetic field of the rotor magnet generates torque in the direction of rotation before stopping. When the direction in which the protrusion of the auxiliary yoke attracts the rotor magnet closest to it is the same as the direction of rotation before it stops, there is a difference between the drive coil side that is currently supplying current and the drive coil side that is not currently supplying current. Both directions of torque act on the direction of rotation before stopping. Also, if the direction in which the protrusion of the auxiliary yoke attracts the rotor magnet closest to it is opposite to the direction of rotation before stopping, the torque generated in the drive coil that is currently supplying current is greater than the torque that is generated in the drive coil that is currently supplying current. Since the attraction force acting on the protrusion of the auxiliary yoke provided below the drive coil is larger than the attraction force acting on the protrusion of the auxiliary yoke, the torque acting on the rotor shaft 71 is applied in the direction of rotation before stopping. Therefore, by removing the cause of stopping the motor, the motor can be restarted.

(f) Example This invention will be explained below with reference to Examples.

FIG. 1 shows a two-phase driving force type brushless flat motor, FIG. 2 shows a longitudinal section thereof, and FIG. 3 shows a cross section thereof. Fourth
FIG. 5 is an explanatory diagram of motor rotation taken along the line A--A in FIG. 3.

(1) is a two-phase driving force type branless flat motor. 2
As shown in Figure 1, the phase drive type brushless flat motor (1) has a stator frame (2) that is stationary during driving.
and a rotor frame (3) that rotates when driven.

(4) is the rotor shaft. Rotor shaft (4)
is provided at the center of the rotor frame (3) so as to protrude toward the stator frame (2).

(5) is a rotor magnet. Rotor magnet (
5) is fixed to the rotor frame (3) so that the distance between the rotor magnets (5) and the adjacent rotor magnets (5) is constant on the circumference of the rotor shaft (4).

(6) is an oil-less metal. The oil-less metal (6) is fixed to the center of the stator frame (2) so as to pivotally support the rotor shaft (4).

(7) is a printed circuit board. The printed circuit board (7) is
The drive coil (8) is fixed to the stator frame (2) so as to face the rotor magnet (5), and the drive coil (8) is attached to the rotor magnet (5) to the -diameter of the stator frame (2).
Fix it so that it is facing. Furthermore, printed circuit board (7)
A through hole (9) is located on the inner surface of the drive coil (8).
). (10) is an auxiliary yoke. The auxiliary yoke (10) is made of a soft magnetic material, and as shown in Figs. A magnetic circuit is formed with the magnet (5) to increase the magnetic flux density in the air gap and increase the motor torque output. In addition, in order to minimize the influence of iron loss, the diametrical portion of the rotation area of the rotor magnet (5) of the auxiliary yoke (10) is made equal to the width of the drive coil (8), so that the magnetic field of the rotor magnet (5) acts on the auxiliary yoke (10). They are connected at the parts that do not meet each other, making them a whole.

Furthermore, when the auxiliary yoke (10) is attached to the printed circuit board (7), the protrusion (11) that can be inserted into the through hole (9) of the printed circuit board (7) is inserted into the rotor magnet ( 5) Provided to protrude toward the rotor magnet (5) along the inner surface in the rotational direction.

In this way, after the two-phase driving force type brushless flat motor (1) in the rotating state is stopped by providing the protrusion (11), it can be driven again as follows by supplying current to the drive coil (8). can do. Drive coil (8
) by stopping the current supply to the brushless flat motor (
1), when the drive coil (8) loses its current magnetic field, the torque due to interaction with the magnetic field of the rotor magnet (5) becomes zero. Furthermore, the auxiliary yoke (10)
Since it is made of a soft magnetic material, the auxiliary yoke (10) is attracted by the magnetic force of the rotor magnet (5), and the point where the attraction by the magnetic force of the rotor magnet (5) is maximum, that is, rotor magnet -8= of the net (5). The center of the magnetic pole and the protrusion (11) of the auxiliary yoke (10) stop at a position substantially aligned perpendicularly to the rotating surface of the rotor magnet (5). Therefore, when a current is supplied to the drive coil (8) from a stopped state and a current magnetic field is generated in the drive coil (8), the magnetic pole center of the rotor magnet l-(5) and the drive coil (8) contribute to torque generation. Since the width centers of the rotor magnet (5) in the rotating direction do not match, the magnetic field of the rotor magnet (5) and the drive coil (8)
) due to the interaction of the current and magnetic field of the rotor magnet (
5) Torque is generated and startup is possible. Furthermore, while supplying current to the drive coil (8), the protrusion (
When the motor rotation stops at a mutual position where the rotor magnet (5) and the rotor magnet (5) almost coincide with each other in the vertical direction of the rotation surface of the rotor magnet (5), by removing the cause of the stop, the rotor magnet (5) Due to the mutual position of the magnetic field of the drive coil (8) and the current magnetic field of the drive coil (8), the motor starts to rotate in the direction of rotation before stopping.

In addition, if the rotation stops intentionally or due to some external factor at a mutual position where the magnetic pole center of the rotor magnet (5) and the center of the width of the rotor magnet (5) in the rotational direction of the drive coil (8) coincide, The magnetic pole center of the current magnetic field generated in the drive coil (8) that is currently supplying current is not symmetrical on both sides of the width center in the rotational direction of the rotor magnet (5) of the drive coil (8), and the auxiliary yoke (1, 0) to the rotor magnet (5) of the drive coil (8).
A protruding portion (11) from the center of the width of the rotor magnet (5) in the rotation direction of the drive coil (8) by the amount provided on the inner surface in the rotation direction.
lean to the side. Due to this bias of the current magnetic field, the interaction between the magnetic field of the rotor magnet (5) and the current magnetic field of the drive coil (8) does not act in the direction perpendicular to the rotating surface of the rotor magnet (5), thereby producing torque.

In this embodiment, the protrusion (11) of the auxiliary yoke (10)
was provided on the inner surface of the drive coil (8) in the direction of rotation of the rotor magnet (5), but suppose it is provided on the inner surface of the drive coil (8) in the direction opposite to the direction of rotation of the rotor magnet (5), as shown in FIG. In this case, if the current supply to the drive coil (8) is stopped and the drive coil (8) comes to a natural stop, the projection of the auxiliary yoke (10) (
11) is the center of the magnetic pole of the rotor magnet (5) and the rotor magnet.

(5) Stop at a position that is approximately perpendicular to the rotating surface. Therefore, in order to rotate the motor again, when current is supplied to the drive coil (8), as shown in Fig. 5, the width center of the rotor magnet (5) of the drive coil (8) to which the current was supplied is the rotor magnet (5). Since the rotor magnet (5) is located on the pre-stop rotation direction side of the magnetic pole center, the attractive force of the magnetic field of the rotor magnet (5) and the current magnetic field of the drive coil (8) acts in the pre-stop rotation direction. However, since the torque due to the attraction force is not sufficient, the center of the magnetic pole of the rotor magnet L-(5) and the drive coil (
8) The rotor magnet l-(5) width center in the rotational direction matches 1. In the saw state, the attraction force is maximum, and on the other hand, the protrusion (11) of the auxiliary yoke (lO) installed on the inner surface of the drive coil (8) to which no current is currently supplied and the rotor magnet l-
The attractive force with (5) also does not work in the rotational direction, and the magnetic pole center of the rotor magnet (5) and the width center of the rotor magnet (5) in the rotational direction of the drive coil (8) almost match, and the machine stops and cannot be restarted. . In addition, when current is being supplied to the drive coil (8), the protrusion (11) of the auxiliary yoke (10) and the rotor magnet (5) may be damaged intentionally or due to some external factor. ) When the motor rotation stops at a mutual position that almost coincides with the vertical direction of the rotating surface, it cannot be restarted for the following reasons even if the cause of the motor stop is removed. The protrusion (11) of the auxiliary yoke (10) is connected to the rotor magnet (5) of the drive coil (8).
) is provided on the inner surface opposite to the rotation direction of the protrusion (1
1) and rotor magnet (5) are rotor magnet (
5) At mutual positions that almost coincide with the direction perpendicular to the rotating surface, the current magnetic field of the drive coil (8) currently supplying current and the magnetic field of the rotor magnet (5) attract each other through interaction, and the rotor magnet ( 5) remains stopped and cannot be restarted.

(G) Effects of the Invention Therefore, by providing a brushless flat motor as described above, when the current supply to the motor is stopped and the motor rotation is stopped and then restarted, the relative position of the drive coil and rotor magnet can be adjusted. can always be stopped in a position where it can be restarted. or,
Even if the rotation of the motor stops intentionally or due to some external factor while current is being supplied to the drive coil of the motor, the motor can be restarted by removing the cause. Therefore, it is possible to eliminate a position where the motor cannot be restarted after stopping during the entire rotation angle of the motor.

[Brief explanation of drawings]

FIG. 1 shows a two-phase drive type brushless flat motor, FIG. 2 shows a longitudinal section thereof, and FIG. 3 shows a cross section thereof. Fourth
FIG. 5 is an explanatory view of the motor rotation taken along the line Δ-Δ in FIG. 3. ■・・・Two-phase driving force type brushless flat motor 2 ・
... Stator frame 3 ... Rotor frame 4 ... Rotor shirt) 5 ... Rotor magnet 6 ... Oil-less metal 7 ... Printed circuit board 8 ... Drive coil 9 ...Through hole 10...Auxiliary yoke 11...Protrusion Patent applicant Naiko Electronics Co., Ltd. Representative patent attorney
Tadashi Yasuhara 2nd Masayoshi Yasuhara 1st
Figure 3 Figure 2 Figure 4 Figure 5

Claims (1)

[Claims] A brushless flat panel characterized in that an auxiliary yoke made of a soft magnetic material is provided on a portion of the drive coil that contributes to torque generation opposite to the rotor magnet side, and a protrusion that protrudes from the inner surface of the drive coil is provided on the auxiliary yoke. motor.