JPS6334464Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a face-to-face commutatorless motor.

For example, a conventional face-to-face non-commutator motor used to drive a capstan shaft of a tape recorder has a rotor 2 which is integrally coaxial with a capstan shaft 1 and also serves as a flywheel, as shown in FIG.
An annular rotor magnet 3 having a plurality of magnetic poles is fixed to the lower surface of the rotor magnet 3, and a position detection element (3) for detecting the drive coil 5 and the magnetic poles of the rotor magnet 3 is attached to the upper surface of the stator core 4, which is provided facing the rotor magnet 3. For example, a Hall element 6 is provided. However, in the conventional electric motor described above, when providing the drive coil 5, the stator core 4
A hole is drilled in the hole, and an eyelet 7 is inserted through the coil 5.
The position detection element 6 is arranged in a hole 8 made in the stator core 4. Therefore, according to the above-mentioned conventional example, since the drive coil mounting hole and the position detection element mounting hole 8 are formed in the stator core 4, the portions of these holes form an air gap, and the magnetic resistance partially increases. However, this was the cause of Kotsuking. However, if the rotor is large and enough inertia can be obtained, this is not a big problem, but as the rotor becomes smaller and lighter and the inertia becomes smaller, the sagging phenomenon increases, and the smaller and lighter electric motor becomes necessary. The drawback was that it was difficult.

An object of the present invention is to provide a surface-facing type non-commutator motor that eliminates the "knocking" phenomenon and can be made smaller and lighter.

The present invention will be explained below with reference to illustrated embodiments.

In FIGS. 1 to 3, a capstan shaft 11, which is the rotating shaft of the electric motor, is press-fitted and fixed to a rotor 12, which also serves as a flywheel, with the required inertia. A multi-pole magnetized annular rotor magnet 1 is placed in the concave part.
3 is fixed. The capstan shaft 11 is supported by a thrust receiver 15 fixed on the stator core 14, and has a base plate 17 fixed at a predetermined distance in parallel to the stator core 14 through support columns 16, 16. It is inserted into a bearing holder 19 which is fixed between a mechanical chassis 18 which is fixed in parallel above the base plate 17 at a predetermined distance. Bearing metals 19a, 19a are fitted into both ends of the bearing holder 19, and the capstan shaft 11 is rotatably supported by these bearing metals 19a, 19a. The stator core 14 is formed into a flat plate shape. On the stator core 14, a plurality of drive coils 20 are arranged concentrically with the capstan shaft 11 at a predetermined circumferential angle, and the upper surface of each coil 20 and the rotor magnet 13 and are opposed to each other with a predetermined gap therebetween. Further, on the stator core 14 made of an iron core, a position detection element 21 for detecting the magnetic pole of the rotor magnet 13 made of a Hall element or the like is placed at a position facing the rotor magnet 13.
21 is fixed, and by controlling energization to the drive coil 20 based on this detection signal, the rotor magnet 13 and rotor 12 rotate as a well-known non-commutator motor, and the capstan shaft 11 is rotated integrally with the rotor 12. It's supposed to rotate. A concave portion 12a is also formed on the upper surface of the rotor 12, and internal teeth 22 are formed in the shape of an internal gear on the inner peripheral surface of this concave portion 12a. Upper and lower yokes 23 and 24 of a frequency generator fixed to the lower end of the bearing holder 19 are located in the recessed portion 12a, and a ring-shaped excitation ring is formed between the yokes 23 and 24 at the inner circumference thereof. A power generating coil 26 wound in a ring shape in the circumferential direction is further disposed on the outer side of the magnet 25. Gear-shaped external teeth 23a are formed on the outer periphery of one yoke 23 of the frequency generator, and the internal teeth 22 and external teeth 23a face each other with an appropriate interval. The power generating coil 26 detects magnetic changes between the internal teeth 22 and the external teeth 23a due to the rotation of the rotor 12, outputs a signal corresponding to the rotation speed of the rotor 12, and based on this detection signal, the driving coil 20 By controlling the energization to the rotor 12, the rotor 12 is rotated at a constant rotation speed.

A printed wiring board 27 is fixed to the lower surface of the stator core 14. A drive control circuit for obtaining output signals of the position detection elements 21, 21 and output signals of the frequency generator to control energization of the drive coil 20 is configured on the printed wiring board 27. A constituting circuit element group 28 is arranged. The stator core 14 has no holes in the area facing the annular rotor magnet 13, and the air gap between the stator core 14 and the rotor magnet 13 is uniformly formed. Elongated holes 14a and 14b are formed in the outer and inner sides of the annular opposing planes of the rotor magnet 13, respectively, and the long holes 14a and 14b have concentric circular arcs.
The lead terminals 21a, 21a of 1 are inserted and further soldered to predetermined positions on the printed wiring board 27, so that the position detection elements 21, 21 straddle the plane facing the rotor magnet 13 in the radial direction. attached. Further, a plurality of through holes 15a are bored around the thrust receiver 15 located inside the surface facing the rotor magnet 13, and the lead wires 20a of each drive coil 20 are inserted into these through holes 15a. The lead wire 20 is inserted through the
Further, a is soldered to a predetermined position on the printed wiring board 27.

In this way, since the area of the stator core 14 facing the rotor magnet 13 is formed without holes, the lead wires 21a, 21a of the position detection elements 21, 21 tend to be long, making it easy to pick up external noise. However, as described above, by arranging the position detection elements 21, 21 in the radial direction, this problem is prevented.

As described above, according to the present invention, the stator core 14 made of an iron core has no holes within the range of the surface facing the rotor magnet 13, and the air gap between the stator core 14 and the rotor magnet 13 is made uniform, so that the magnetic resistance is reduced. It does not increase locally, but becomes uniform, and the conventional drawback that the magnetic action with the rotor magnet 13 changes locally and causes cocking can be completely eliminated. This effect means that even if the rotor is made smaller and lighter and the inertia is smaller, stable rotation without jerking can be expected, which has the effect of making it possible to make the electric motor smaller and lighter. . In addition, if there is any cocking, it will cause vibration of the rotor magnet and generate mechanical noise, and if it has a frequency generator, it will also cause a change in the interval between the internal teeth 22 and external teeth 23a. The output of the frequency generator is modulated by the above-mentioned vibration frequency, which causes wow and flutter, but according to the present invention, the above-mentioned twitching is prevented and there is no vibration, so the frequency generator is modulated by the vibration frequency. The output of the machine is also accurate, and wow and flutter are greatly improved. According to experiments, mechanical noise was improved by more than 10 dB, and wow and flutter were improved by about 0.005 or more.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional front view showing an embodiment of the present invention, Fig. 2 is a plan view of the same, Fig. 3 is an enlarged sectional front view of the main part of the same, and Fig. 4 is a conventional surface-facing non-commutator motor. FIG. 12... Rotor, 13... Rotor magnet,
14...Stator core, 18...Mechanical chassis,
20... Drive coil, 21... Position detection element, 1
4a, 14b...Through hole.

Claims (1)

[Scope of utility model registration request] An annular rotor magnet having a plurality of magnetic poles held by a rotor fitted with a rotating shaft, a plurality of drive coils arranged close to the rotor magnet, and a flat plate-shaped rotor magnet on which the drive coils are arranged. and a position detection element disposed on the stator core to detect the magnetic pole position of the rotor magnet, the stator core having a surface facing the rotor magnet without holes. forming a uniform air gap between the rotor magnet and the rotor magnet, and forming a through hole outside the range of the surface facing the rotor magnet;
A face-to-face non-commutator motor in which lead wires of the position detection element and the drive coil are inserted through holes in the stator core.