JPS6219094Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor rotor equipped with a shutter portion for detecting a rotational position with a photodetector.

Brushless motors need to switch the current-carrying coil or switch the current-carrying direction according to the rotational angle of the rotor, and for this purpose, a rotor rotational position detection device is provided. As such a rotational position detection device, one using a photocoupler is known. This position detection element has a fan-shaped or semi-cylindrical shutter attached to the periphery of the rotor of the motor, so that the shutter can also block the optical path between the light-emitting element and the light-receiving element of the photocoupler within a predetermined rotational angle range. This is what I did.

In such a brushless motor, if there is an error in the timing of current switching of the stator coil, the output of the motor decreases or torque ripple increases. Therefore, in order to match the phase relationship between the coil flux linkage waveform and the current switching signal (adjust the neutral point), the positional relationship between the position detection element (photocoupler) and the coil or the field magnet and shutter must be adjusted. The configuration is such that any of the positional relationships between the two can be adjusted. Since such neutral point adjustment work is performed while the motor is rotating, the positional relationship between the coil on the stator side and the position detection element is usually adjusted.
Therefore, the positional relationship between the field magnet and the shutter is fixed at a predetermined phase relationship relative to the magnetic poles of the magnet during rotor assembly.

In this case, in order to align the shutter and the magnet during assembly, it is necessary to form some kind of matching mark or unevenness on the magnet and the shutter or the rotor yoke, which poses a problem that the production characteristics of the parts deteriorate. Further, during assembly, there are problems in that the number of assembly steps increases and it is difficult to achieve positional accuracy between the magnet and the shutter.

The present invention has been developed in view of the above-mentioned problems, and it is possible to accurately determine the positional relationship between the shutter and the magnet in relation to the magnetic pole position of the magnet during assembly, and it also simplifies this work. In addition, we aim to simplify the component parts.

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a vertical sectional view of a motor showing an embodiment in which the present invention is applied to a two-phase six-pole flat brushless motor, Fig. 2 is a plan view of the stator shown in Fig. 1, and Fig. 3 is a field magnet. FIG. 4 is a plan view of the shutter member, and FIG. 5 is a side view of the shutter member partially cut away along line - in FIG. 4.

In FIG. 1, a motor shaft 3 is fixed via a boss 2 to the center of a disk-shaped rotor yoke 1 made of a magnetically permeable material. The motor shaft 3 is rotatably supported by bearings 6 and 7 within a cylindrical shaft support 5 attached to the center of the motor case 4.
The shaft 3 is a disk-shaped stator yoke 8 which is a magnetically permeable body.
It is supported in the axial direction by a bearing 9 mounted at the center. A shutter member 10 shown in FIGS. 4 and 5 is mounted on the stator side surface of the rotor yoke 1.
is fixed by adhesive. A plurality of field magnets 15 are arranged in each frame formed by the magnet positioning frame portion 13 of the shutter member 10 as shown in FIG.
It is fixed with adhesive on the back side of.

A magnet 15 is placed on the surface of the stator yoke 8.
The coil 16 is fixed in a state facing the.
Further, a photocoupler 18 for detecting rotational position is arranged on the stator yoke 8, sandwiching an arcuate shutter 17 formed on the periphery of the shutter member 10.

As shown in FIG. 2, the coils 16 are each composed of three sets of two-phase (A-phase and B-phase) coils LA1 to LA3 and LB1 to LB3. The winding pitch (center angle of the motor's radial direction) of each coil is approximately 40° (120° in electrical angle), and the A-phase and B-phase coils are arranged with a phase difference of 60° (180° in electrical angle). has been done. Also, A phase (B phase) coils LA1 to IA
3 (LB1 to LB3) are each 120° (360 in electrical angle)
They are arranged with a phase difference of .degree.) and are connected in series.

The field magnet 15, as shown in FIG.
Three main magnets M1 to M3 with a center angle of 90°
(6 poles in total) and three commutator magnets SM1 to SM3 with a center angle of 30 degrees. As shown in FIG. 3, each of the magnets M1 to M3 and SM1 to SM3 is magnetized in the thickness direction of the magnet to N and S poles along the circumferential direction. Furthermore, the third
For example, as shown by the dotted line in the figure, the main magnet M2
S pole part (135° electrical angle), interpolation magnet
An electrical angle of 360° (120° in positional angle) is formed by SM2 (90° in electrical angle) and the N-pole portion (135° in electrical angle) of main magnet M3.

As shown in FIGS. 4 and 5, the shutter member 10 is made of synthetic resin and molded into a water wheel shape. Note that the shutter member 10 and the magnet 1
Since the rotor assembly is placed in a high-temperature furnace when the rotor assembly 5 is adhesively fixed to the rotor yoke 1, the shutter member 10 is desirably made of a highly heat-resistant resin material such as polybutylene terephthalate resin. The central angle of each of the three shutters 17 formed on the outer peripheral portion 21 of the shutter member 10 is
60° (180° in electrical angle), and each shutter 17 is arranged with a phase difference of 120° (360° in electrical angle).

A ring portion 2 is provided at the center of the shutter member 10.
2 is formed, and this ring portion 22 and the outer peripheral portion 2
The above-mentioned frame portion 13 for positioning the magnet is formed between the magnet and the magnet. Each frame 13 is arranged 90 degrees alternately so as to match the arrangement of the magnets 15 in FIG.
The angular intervals are 30° and 30°. Therefore, frame spaces 14 having central angles of 90° and 30° are alternately formed by the frame portions 13. In addition, shutter 17
Each of the 30 points adjacent to the center of the 90° frame space 14
It is arranged at angular positions spanning 60° to the center of the frame portion 14 of 60°. That is, the angular region from the center of the main magnet (for example, M2) to the center of the commutator magnet (for example, SM2) in FIG.
It has an angle area of 7. Therefore, when the rotor is assembled, the angular relationship between the magnetic pole position of the field magnet 15 and the shutter 17 is mechanically determined for the shutter member 10.

FIG. 6 is an exploded perspective view of the rotor assembly. As shown in FIG. 6, a shutter member 10 is adhesively fixed to the outer periphery of the rotor yoke 1. As shown in FIG. Next, the frame space 1 formed by the frame portion 13 of the shutter member 10 is
4, main magnets M1 to M3 and complementary magnets
SM1 to SM3 are inserted, and these magnets are adhesively fixed to the back surface of the rotor yoke 1. Note that after the rotor assembly is assembled, it is placed in a furnace to harden the adhesive. As described above, the rotor is extremely easy to assemble, and there is no need to align the magnet 15 and the shutter member 10.

Note that instead of the shutter 17, a reflective part is formed on the outer peripheral part 21 of the shutter member 10, for example, by partially pasting metal foil, and a reflective photocoupler is provided on the fixed side opposite to this outer peripheral part 21. Good too.

FIG. 7 is a waveform diagram for explaining the operation of the two-phase six-pole brushless motor of this embodiment. The S pole of the main magnet makes up 360 degrees in electrical angle,
The magnetic flux distribution shown in FIG. 7A is formed by the N and S poles of the interpole magnet and the N pole of the main magnet. That is, the S and N magnetic flux density B formed by the main magnet is relatively high, and the magnetic flux density B formed by the interpolation magnet between them is relatively small. The rotational torque Ti generated by the current flowing through one of the coil parts Li (outgoing path) in the motor radial direction of the A-phase coils LA1 to LA3 in Fig. 2 and the interlinkage magnetic flux of this coil part cannot be changed unless the current is switched. , as shown by the real edge Ti in FIG. 7B, almost coincides with the magnetic flux distribution curve formed by the field magnet 15 (FIG. 7A). In addition, the rotational torque Tj generated by the current in the opposite direction to the above flowing through the coil portion Lj (return path) in the motor radial direction of the A-phase coil and the interlinkage magnetic flux of this coil portion is expressed by the dotted line Tj in FIG. 7B. , the solid line Ti is reversed with the θ axis as the axis of symmetry, and the winding pitch between the coil portions Li and Lj is delayed by 120°. Therefore, A phase coil LA1
~Torque generated by LA3 T _A = Ti + Tj
is an electrical angle of 180, as shown by the dashed-dotted line T _A in Figure 7B.
The torque is almost flat over a range of more than .

B-phase coils LB1 to LB3 have a phase difference of 180 degrees in electrical angle with respect to the A-phase coil, so B
The torque produced by the phase coil is a 180° phase shift of T _A as shown in FIG. 7C. Therefore,
If each coil is switched and energized using the A-phase and B-phase current switching signals S _A and S _B shown in FIG. 7 E and F,
There is no rotational dead center over 360 degrees of electrical angle, and almost uniform torque can be obtained. Furthermore, shutter 1
7 is set at the phase shown in FIG. 7D with respect to the edge of the magnetic flux distribution curve of the magnet 15 (FIG. 7A), as described above. Therefore, on the stator side, the coil 16 is
The phase of the center of the radial part of the motor (A phase) is
For example, the phase difference is 15 degrees in electrical angle. In this case, by adjusting the phase between the coil 16 and the photocoupler 18, the switching points of the current switching signals S _A and S _B shown in FIGS. 7E and F are adjusted, and thereby the neutral point (torque ripple can be adjusted (the point where is the minimum). Note that since the positional relationship between the field magnet 15 and the shutter 17 is set with high precision, adjustment of the neutral point is relatively easy. In addition, shutter 17 and photocoupler 1
8 to form the A-phase current switching signal S _A , B
The phase current switching signal S _B is also formed by the inverse signal of S _A.

As mentioned above, the present invention includes a shutter member that is attached to detect the rotational position of the motor rotor.
The frame for regulating the position of the magnet is integrally formed with the shutter at a predetermined angular relationship from the outer periphery toward the center, which simplifies assembly of the rotor and allows for easy control of the magnetic pole position of the field magnet. The positional relationship with the shutter is determined mechanically with extremely high precision. Therefore, the work of adjusting the positional relationship between the field magnet and the shutter becomes unnecessary or becomes extremely simple. In addition, since the field magnet positioning frame portion clamps each of the plurality of field magnets and regulates their position, there is no need to form markings or unevenness on the rotor yoke and the field magnets, thus improving the productivity of parts. This is good and does not have any adverse effect on the magnetic path that forms the field. Moreover, since the position of the field magnet is regulated by the frame formed to match the outer shape of the magnet, assembly is easy and the magnet can be positioned reliably.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a motor showing an embodiment in which the present invention is applied to a two-phase six-pole flat brushless motor, Fig. 2 is a plan view of the stator of Fig. 1, Fig. 3 is a plan view of the magnet showing the arrangement of the field magnet, Fig. 4 is a plan view of the shutter member, Fig. 5 is a side view of the shutter member partially cut along the line - in Fig. 4, Fig. 6 is an exploded perspective view of the rotor assembly, and Fig. 7 is a waveform diagram explaining the operation of the two-phase six-pole motor shown in Figs. 1 to 6. In addition, in the symbols used in the drawings, 1...
... rotor yoke, 10 ... shutter member, 13
...magnet positioning rim portion, 17...shutter.

Claims (1)

[Scope of utility model registration request] A field magnet consisting of a plurality of magnets,
This shutter member includes a disk-shaped rotor yoke to which a plurality of these magnets are fixed, and a synthetic resin shutter member that is attached to the rotor and has a shutter on its periphery for detecting the rotational position of the rotor with an optical detection means. The shutter is characterized in that a plurality of frame portions are provided from the periphery toward the center of the shutter so as to hold the plurality of magnets in a predetermined angular relationship with respect to the motor rotation direction to regulate their positions. The rotor of the motor.