JPS6135776B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a structure for reducing vibrations of an outer rotor motor that winds yarn or the like.

Fig. 1 is a sectional view showing a conventional induction type outer rotor motor, where 1 is a fixed shaft located at the center of the motor, and 2 is a cylinder attached to the center of the shaft 1 and around which a stator coil 3 is wound. 4 is a bearing fixed to the shaft 1, and 6 is this bearing 4.
6 is a balance ring attached to the bracket 5; 7 is a cylindrical rotor fitted to the outer diameter surface of the two brackets 5; 8 is a rotor that faces the stator core 2; A cylindrical rotor core 9 fixed inside the rotor 7 is a shot ring provided on the side surface of the rotor core 8 and integrated therewith.

This conventional outer rotor motor is different from a commonly used general motor in that the shaft 1 side is fixed to a surface plate and the rotor 7 side is configured to rotate. Therefore, for example, the spun yarn is transferred to the rotor 7.
When winding the stator coil 1, the shaft 1 is fixed to a surface plate, and a current is supplied to the stator coil 3 from the exposed part of the shaft 1 through the inside of the shaft 1 from a lead wire (not shown).
A rotating magnetic field is generated in the stator core 2, the rotor core 8 and the rotor 7 rotate in the same manner as the rotation principle of a general motor rotor, and the thread is wound around the outer surface of the rotor 7.

Even in motors with this type of structure, mechanical imbalances need to be corrected, just like in general rotating machines.
This unbalance was corrected by machining the balance ring 6 or by screwing an additional weight onto the balance ring 6. The best way to correct unbalance is to remove or add weight at the location where the unbalance occurs.In the outer rotor of the above structure, the rotor core 8 has the largest unbalance. Correcting imbalances is difficult. The reason is that the surface of the rotor 7 in the radial direction of the rotor core 8 is the part where the yarn is wound.
It is impossible to attach a weight, and the bracket 5
It is also extremely difficult to attach a weight to the vicinity of the end ring 9 from the side if the shaft 1 is long. Therefore, the balance ring 6 must be selected as the location for correcting the unbalance. However, it is generally necessary to perform balance correction using the rotor core 8 as a correction surface in a high rotation speed region where the rotor 7 is treated as an elastic rotor as shown in FIG. In this case, no matter how much correction weight is added to the balance ring 6 by selecting the balance ring 6 as the correction surface, the efficiency of balance correction is actually poor, so it is imperative to use the rotor core 8 or the end ring 9 as the correction surface. You need to choose.

Furthermore, when a motor with a conventional structure is operated for a long time, the temperature of the rotor 7 and rotor core 8 increases.
The rate of temperature rise around the same radius is generally considered to be slightly different, and this temperature difference causes
The amount of extension of the rotor 7 at the 180° symmetrical position is different, resulting in a state as if the rotor 7 was deformed toward the higher temperature side. This exactly corresponds to the state shown in Figure 2, so in the outer rotor of the conventional structure,
Even if the unbalanced vibration is small when the temperature of the rotor 7 and rotor core 8 is low, the unbalanced vibration increases as the temperature rises.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an outer rotor motor that facilitates correction of mechanical unbalance that occurs during motor manufacturing and that reduces deformation of the rotor as the temperature of the rotor increases.

An embodiment of the present invention will be described below with reference to FIG. That is, in FIG. 3, numerals 1, 3 to 7 indicate the same parts as the conventional one shown in FIG. 21,
22 is a cylindrical stator core attached near both ends of the shaft 1 and around which stator coils 31 and 32 are wound; 81 and 82 are the inner sides of a single cylindrical long rotor 7 facing the stator cores 21 and 22; The cylindrical rotor cores 91 and 92 respectively fixed to the rotor cores 81 and 92 are shot rings provided on the side surfaces of the rotor cores 81 and 82 and integrated therewith.

With this configuration, the rotor cores 81 and 82, which are driven to rotate by an externally supplied voltage, are the same as the conventional one shown in FIG. are located close to the balance ring 6 on the balance correction surface, so that the balance correction can be performed at the balance ring 6, making the balance correction easy.

In addition, when the rotation speed of the rotor 7 is high and the vibration mode of the long rotor 7 becomes as shown in Fig. 2, by adding or removing a counterweight to the balance ring 6, it is possible to achieve a more precise balance than the conventional one. This can be corrected and the vibration of the long rotor 7 can be reduced.

Furthermore, in this configuration, since the two-part rotor cores 81 and 82, which have a large mass, are located near the bearing 4, which serves as a support point, the frequency at which the drive mode shown in FIG. 2 appears, that is, the resonance frequency, is lower than that of the conventional one. This has the advantage of widening the frequency range that the motor can actually use.

In addition, since the two-part rotor cores 81 and 82 are located near the support points, even if the temperature of the rotor 7 rises due to long-term use, even under the same conditions as the conventional one, the bending moment due to heat Since this is extremely small, the amount of deformation of the long rotor 7 is also extremely small, and there is an advantage that the vibration of the long rotor 7 during rotation can be kept small.

Further, the stator cores 2, 21, 22 and the rotor cores 8, 81, 82 are respectively connected to the shaft 1 and the long rotor 7.
It is necessary to fix the cores by shrink fitting or gluing, but with conventional structures, it is difficult to fix each core to the center of the motor.
For example, when shrink-fitting the rotor core 8 to the long rotor 7, the rotor core 8 and the rotor 7 that is not shrink-fitted
It is necessary to remove the inner surface larger than the outer diameter of the rotor core 8 and finish the shrink fit part with high precision, but it is structurally difficult to process and difficult to assemble.

However, in the case shown in FIG. 3, it is only necessary to process and assemble the parts near the ends of the shaft 1 and the elongated rotor 7, which makes the work easier.

The outer rotor motor according to the present invention has a pair of stator cores provided at both ends of a shaft, a single long cylindrical rotor rotatably mounted around the shaft, and the stator core mounted on the inner surface of the long rotor. A pair of rotor cores are provided facing each other, which not only facilitates processing and assembly, but also
The unbalance of the long rotor can be easily corrected, and vibrations are reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing a conventional outer rotor motor, FIG. 2 is a schematic diagram for explaining the operation of the motor shown in FIG. 1, and FIG. 3 is a sectional view showing an embodiment of the present invention. In the figure, 1 is the shaft, 2, 21, 22 are the stator cores,
4 is a bearing, 5 is a bracket, 6 is a balance ring, 7 is a long rotor, 8, 81, 82 are rotor cores, and 9, 91, 92 are shot rings. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A pair of stator cores attached to both ends of a shaft with a long interval in the axial direction, a single long cylindrical rotor rotatably mounted around the shaft,
An outer rotor motor including a pair of rotor cores provided on the inner surface of the elongated rotor to face the stator core. 2. The outer rotor motor according to claim 1, wherein the long rotor is mounted on the shaft by a bracket. 3. The outer rotor motor according to claim 2, wherein a balance ring is attached to the bracket.