JP3046048B2 - Brushless motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thin, high-output, flat brushless motor used for a small-sized tape recorder or the like.

[Conventional technology]

In recent years, with the miniaturization of tape recorders, flat type brushless motors have been widely used, and the demand for high output type motors has been increasing. As shown in a side view of FIG. 12, a brushless motor used in a conventional tape recorder has a rotor or sub-rotor having a stator coil and a permanent magnet housed in a brushless motor main body 101, and a rotor outside the rotor. The shaft 102 protrudes. A pulley 103 is provided on the rotor shaft 102, and the pulley 103
Is configured to output the driving force to the outside.

[Problems to be solved by the invention]

However, in such a conventional brushless motor, no matter how thin the stator coil or the rotor of the motor body is, the rotor shaft and the pulley are protruded, so that there is a limit to the thinning of the entire motor including the rotor shaft and the pulley. there were. In particular, when a permanent magnet is provided as a sub-rotor in order to obtain a high output, there is a problem that the motor body is further thickened. In addition, there is a problem that the configuration of the motor is completely different between a case where a permanent magnet is provided and a case where a permanent magnet is not provided in the sub-rotor due to a demand for high output.

SUMMARY OF THE INVENTION The present invention has been made in view of such problems of the conventional brushless motor, and has as its technical object to provide a brushless motor having a reduced thickness, high output, and low power consumption.

[Means for solving the problem]

The invention according to claim 1 of the present application is directed to a fixed bracket formed of a metal member having a magnetic shielding function in a cup shape, a bearing member fixed to a central portion of the bracket, and a rotatable shaft via a bearing member and a bearing. A supported rotating shaft, a pulley fixed to a part of the rotating shaft and having a belt groove formed in a central portion in the axial direction, and attached to a part of a bracket, and a plurality of driving coils are formed in a planar shape. A central portion of the substrate is opened as a rotor shaft hole so that the pulley can rotate, and a sector shape is formed from the central portion of the substrate toward the outer periphery so as to be a passage of a belt inserted into a belt groove of the pulley. A stator having a cut-out portion is attached to one end in the axial direction of a pulley so as to face a driving coil of the stator with a certain gap, and is magnetized to a plurality of poles along a circumferential direction. The rotor with the first magnet attached thereto is attached to the other end in the axial direction of the pulley so as to face the driving coil of the stator with a certain gap therebetween, and is substantially the same as the first magnet of the rotor. And a sub-rotor having the second magnet having the magnetized pattern described above.

[Action]

According to the present invention having such a feature, by sequentially driving the drive coils of the stator, a repulsive force acts between the permanent magnets of the rotor provided in a position close to the drive coils, and the rotor rotates the rotating shaft. It will rotate around the center. Then, the belt is engaged with a pulley rotatably held at the center of the stator, so that a rotational force is extracted from the belt. Further, by using a sub-rotor having the same permanent magnet as the outer peripheral portion of the rotor so as to sandwich the drive coil of the stator, a strong rotational force is obtained. Further, by using a plate-shaped sub-rotor without a permanent magnet for the stator, the thickness of the motor itself is reduced so as to extract the rotational force of the rotor.

〔Example〕

FIG. 2 is a front view showing the structure of a brushless motor according to one embodiment of the present invention, and FIG. 3 is a side view thereof. FIG. 1 is a sectional view taken along line AA. As shown in these figures, the brushless motor according to the present embodiment is provided with a disk-shaped stator 1 integrally formed with a drive coil 1a. A terminal 1c is formed on a terminal holding member 1b outside the circumference of the stator 1, and a rotor shaft hole 1d is formed in the center of the stator 1. As shown in FIG. 4, the drive coil 1a of the stator 1 has six coils L1a, L2a,... A fan-shaped notch 1e is provided between the drive coils L1a and L3b. In FIG. 1, a rotor 2 is rotatably held below a stator 1. The rotor 2 is a disk-shaped member, and holds the first permanent magnet 2a so as to face the drive coil 1a. permanent magnet
For example, 2a is 12-pole magnetized as shown in FIG. 5, and is configured so that the magnetization angle pitch is 30 ° each. A pulley 2b is provided at the center of the rotor 2, and a shaft 2c is provided at the center thereof. A belt groove 2d having a V-shaped cross section is formed on the outer periphery of the pulley 2b. FIG. 6 shows a front view of the stator 1 from which a sub-rotor described later has been removed, and FIG.
FIG. As shown in FIGS. 1, 6, and 7, a cylindrical convex portion 2e is formed on the upper portion of the pulley 2b.

On the other hand, the bracket 3 is provided with a bearing member 3a having a bearing 3b and a thrust plate 3c. A bent shield plate 3d is provided on the outer peripheral portion. The shield plate 3d reduces the influence of the radiation of electromagnetic waves from the rotor 2 and the stator 1 on the main body of the device such as an amplifier circuit, a tuner circuit, and a magnetic head. The bracket 3 is provided with a plurality of columns 3e for supporting the stator 1. Further, a sub-rotor 4 is provided above the stator 1 at a position facing the rotor 2. The sub-rotor 4 has a second permanent magnet 4a having the same shape as the permanent magnet 2a.
A sub-rotor holding member 4b fixed to the projection 2e is provided. The holding member 4b of the sub-rotor 4 is formed by a protrusion 2e of the pulley 2b.
And the stator 1 is sandwiched between the permanent magnets 4a and 2a. Bracket 3 is rotor 2
And the sub-rotor 4 is integrally rotatably held. In order to make the notch 1e at the center of the stator 1 as small as possible, the projection 2e of the rotor 2 and the holding member 4b of the sub-rotor are attached and connected. The distance between the drive coil 1a of the stator 1 and the permanent magnets 2a and 4a is made equal.

As shown in FIGS. 1, 6 and 7, a belt 5 is provided in the notch 1e of the stator 1. The belt 5 is stretched around the belt groove 2d of the pulley 2b and transmits the rotational force of the rotor 2 to the outside. The stator 1 is mounted on a bracket 3 with screws 6.
Is fixed to the column 3e.

Each of the coils L1a to L1 of the driving coil 1a thus configured
3b, the coils L1a and L1b are directly connected and connected to the terminal 1c1, and the coils L2a and L2b are connected in series and connected to the terminal 1c2, and the coils L3a and L3b are connected in series as shown in FIG. Connected to terminal 1c3. And coils L1a, L2a, L
The other contacts of 3a are commonly connected and connected to a terminal 1c4, and the control circuit 7 is connected to drive these coil groups. Then, as shown in FIG. 9, the terminals 1c of the stator 1 are protruded above the terminal holding members 1b so that the terminals 1c can be easily connected to the printed wiring board 8.

Thus, in the brushless motor of the present invention, the pulley 2b
The belt 5 that engages with the belt 1 is pulled out through the notch of the stator 1. Therefore, unlike the conventional brushless motor, the belt is pulled out from the motor body, so that the thickness of the motor including the pulley can be significantly reduced.

Next, a second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the same parts as those in the first embodiment described above are denoted by the same reference numerals, and detailed description is omitted. In this embodiment, a 12-pole permanent magnet 11a similar to that of the first embodiment is attached to the sub rotor 11. The sub-rotor 11 is not provided with a sub-rotor holding member, but is provided with a recess 11b at the center thereof to be attached to the convex portion 2e of the pulley 2b of the rotor 2. In this case, the depth of the recess 11b is determined so that the distance between the stator 1 and the permanent magnet 11a is the same as in the first embodiment. The diameter of the recess 11b is made equal to the diameter of the sub rotor holding member 4b so that the sub rotor 11 can be mounted in place of the sub rotor 4. Also in this case, similarly to the first embodiment described above,
The rotor sandwiched between the pair of permanent magnets can be rotated by energizing the drive coil 1a of the stator.

FIG. 11 is a diagram showing a configuration of a brushless motor according to a third embodiment of the present invention. Also in this embodiment, the same parts as those in the above-described first embodiment are denoted by the same reference numerals, and detailed description is omitted. In this embodiment, a flat sub-rotor 12 is provided in place of the sub-rotor 4, and the sub-rotor 12 is attached to the convex portion 2e of the rotor 2. Here, the thickness is determined so that the distance between the sub-rotor 12 and the stator 1 is the same as the distance between the stator 1 and the permanent magnet 2a.
The diameter of the sub rotor 12 is set to be the same as the diameter of the sub rotor holding member 4b. In this case, different types of brushless motors can be configured only by replacing the sub rotor. In this embodiment, since the sub-rotor 12 has no permanent magnet, the entire motor can be reduced in thickness.

〔The invention's effect〕

As described above in detail, according to the present invention, by pulling out the belt engaged with the pulley at the center of the rotor from the notch formed in the stator, it is possible to significantly reduce the thickness compared to the conventional brushless motor. Can be. Further, by pulling out the belt from the notch of the stator, a high rotational output can be obtained, and power consumption can be reduced.

According to the second aspect of the present invention, the sub-rotor holding member is provided and connected to the shaft of the rotor. In this way, the sub-rotor having no permanent magnet can be used irrespective of the presence or absence of the permanent magnet, and a thinner or higher output can be achieved by replacing the sub-rotor with almost no change in the shape of the motor body according to the purpose. The effect that it can be obtained is also obtained.

[Brief description of the drawings]

FIG. 1 shows a brushless motor A according to an embodiment of the present invention.
FIG. 2 is a front view of the brushless motor of this embodiment, FIG. 3 is a side view thereof, FIG. 4 is a driving coil of a stator, and FIG. 5 is a magnetic pole distribution of a permanent magnet of a rotor. FIG. 6 is a front view of the brushless motor with the sub-rotor removed, FIG. 7 is a front view of the brushless motor with the stator drive coil removed, and FIG. 8 is a drive of the stator drive coil. FIG. 9 is a diagram showing an electric configuration for the motor, FIG. 9 is a diagram showing a connection state of a driving coil of a stator and its mounting portion and a terminal member, FIG. 10 is a cross-sectional view of a brushless motor according to a second embodiment of the present invention, FIG. 11 is a sectional view of a brushless motor according to a third embodiment of the present invention, and FIG. 12 is a side view showing an example of a conventional brushless motor. 1 ... stator, 1a ... drive coil, 1c ... terminal, 1d ...
... rotor shaft hole, 2 ... rotor, 2a, 4a, 11a ... permanent magnet, 2b ... pulley, 2c ... shaft, 2e ... convex portion, 3 ... bracket, 3b ... bearing, 3c ... thrust Plate, 3d: Shielding plate, 4, 11, 12: Sub-rotor, 4b: Sub-rotor holding member, 5: Belt.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-250653 (JP, A) JP-A 64-34864 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H02K 21 / 00,29 / 00 H02K 7/10

Claims (3)

(57) [Claims] A fixed bracket formed of a metal member having a magnetic shielding function in a cup shape; a bearing member fixed to a central portion of the bracket; and a rotatably supported bearing via the bearing member and a bearing. A rotating shaft, a pulley fixed to a part of the rotating shaft and having a belt groove formed in a central portion in an axial direction, and a plurality of driving coils mounted on a part of the bracket and having a planar shape. A central portion of the substrate is opened as a rotor shaft hole so that the pulley can rotate, and a central portion of the substrate is formed as a passage of a belt inserted into a belt groove of the pulley. A stator having a notch cut in a fan shape toward the outer periphery, and attached to one end of the pulley in the axial direction so as to face a drive coil of the stator with a certain gap therebetween. A rotor having a first magnet magnetized to a plurality of poles along the circumferential direction, and the other end in the axial direction of the pulley facing the drive coil of the stator with a certain gap therebetween. And a sub-rotor mounted and having a second magnet having a magnetization pattern substantially the same as the first magnet of the rotor. 2. The brushless motor according to claim 1, wherein the sub-rotor is attached to the other end of the pulley in the axial direction via an annular sub-rotor holding member. 3. The brushless device according to claim 1, wherein the pulley has a recess cut out along a central axis, and the bearing member is located in the recess. motor.