JPS5931197B2 - coreless motor - Google Patents

Description

[Detailed description of the invention] The present invention relates to the structure of a coreless motor.

Generally speaking, as shown in Figure 1, in a coreless motor, from the center of the commutator plate opening attached to one open end of the coil tube,
A rotor is constructed by protruding a shaft 2 (2) toward the center of the inner space of the coil tube (A), and the shaft (2) is rotatably inserted into the bearing (E) of the stator. Even if the shaft protruding outward is equipped with an E-ring and the commutator plate is installed with the mouth facing downward, the brush plate will not be pressed excessively by the weight of the rotor itself. This was to prevent this from happening. However, in the rotor of such a conventional coreless motor, the rotor is shifted by the gap between the E-ring and the bearing hole, so the brush wheel is loaded by that gap and wears out quickly. 3. Disadvantage: The present invention was made in view of this fact, and aims to prevent an excessive load from being applied to the brush regardless of the mounting direction of the coreless motor. Fig. 2 is a sectional view of the coreless motor of the present invention equipped with a rotor, Fig. 3 is a perspective view of a commutator plate,
FIG. 4 is a sectional view of the rotor.

In the figure, 1 is a coil tube, 2 is a commutator plate attached to one opening window of the coil tube 1, and 3 is a shaft protruding from the center of the commutator plate 2 toward the center of the tube. The rotor A is configured as follows.

Here, the commutator plate 2 of this rotor A is shown in FIGS. 3 and 4.
As shown in the figure, a slit 2a is formed which is inclined in the direction of a needle. Further, the inner end of the commutator plate 2 of this slit 2a slightly protrudes from the inner surface thereof. This is because when the rotor A rotates, air from outside the rotor is sent inside. 4 is a permanent magnet, 5 is a yoke, and 6 is a resin in which the permanent magnet 4 is fixed in the center of the interior of the yoke 5, and these constitute the stator B.

Further, a shaft hole T is formed in the center of the resin 6 of this stator B, and bearings 8 are embedded in both open ends of the shaft hole 7.

Thus, the rotor A is rotatably mounted with its shaft 3 inserted into the bearing 8.

The tip of a brush 10 protruding from a holding plate 9 is pressed against the surface of the commutator plate 2 of the rotor A. Note that a washer 11 is installed between the base of the shaft 3 of the rotor A and the bearing 8. Reference numeral 12 designates an E-ring installed close to the bearing 8 of the shaft 3 that projects outward.

Now, when the rotor A rotates, the air inside the rotor A is sent out to the outside since the commutator plate 2 has the inclined slits 2a formed therein. That is, the rotor A is pressed toward the permanent magnet 4 by the blowing action. Due to this pressing force, even if the motor is installed with the brush 10 side facing downward, the weight of the rotor A will cause the E-ring 12 to
The shaft 3 rotates while maintaining the base of the shaft 3 in contact with the other bearing 8 without contacting the bearing 8. Therefore, the force with which the brushes 10 are pressed against the surface of the commutator plate 2 is always maintained substantially constant, thereby preventing an effect that increases the wear of the brushes 10.

As described above, the rotor of the coreless motor of the present invention allows the air in the inner cavity of the rotor to be sent out to the outside through the slits provided in the commutator plate even when the coreless motor is installed with the brush side facing down. Due to the weight of the empty rotor, the rotor does not shift toward the brush side (downward), and the pressure of the brush against the surface of the commutator plate is maintained at a constant level, which prevents premature wear and extends the service life. There is an effect that can be achieved.

[Brief explanation of drawings]

Figure 1 is a sectional view of a conventional coreless motor, Figure 2 is a sectional view of the coreless motor of the present invention equipped with a rotor, and Figure 3 is a sectional view of a conventional coreless motor.
The figure is a perspective view of the commutator plate, and FIG. 4 is a sectional view of the rotor. 1... Coil tube, 2... Commutator plate, 2
a...slit, 3...shaft, A...
...Rotor, 4...Permanent magnet, 5...
・Yoke, 6...Resin, B...Stator, 7...Shaft hole, 8...Bearing, 9...
...Holding plate, 10--Brush, 11-- Washer, 12--E ring.

Claims (1)

[Claims] 1 Forming diagonal slits in the commutator plate to send air from the inner space of the rotor toward the brushes as the rotor rotates;
A coreless motor characterized in that the mounting direction prevents movement of the rotor in the direction of the brushes due to the weight of the rotor, thereby maintaining a substantially constant pressing force of the brushes against the outer surface of the commutator plate.