JPS6173531A - small motor core - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a small motor core that can be used, for example, in a three-slot small DC motor.

Conventional configurations and their problems In recent years, there has been a strong demand for small DC motors to offer high performance and lower prices.Especially when it comes to low prices, cost competition for finished products is fierce, and among the parts used in these products, the motor is Since motors are more expensive than parts, lowering the price of the motor would have a significant effect in reducing costs. Factors that influence the motor cost include the material of the mag green throat, the bearing material, the current-carrying part structure, the number of core slots, etc., and this invention focuses on the number of core slots. Now, it is possible to reduce the coking and torque unevenness of the motor characteristics by increasing the number of core slots, but this also increases the cost as the winding and wiring man-hours increase. Therefore, by using a small number of slots (3 slots) to reduce coking and torque unevenness, a low-cost motor can be provided.

Conventionally, the core of a three-slot small DC moke has a shape as shown in FIG. That is, 30 is a core salient pole right, 31 is a core salient pole left, and 32 is a slot. However, the right salient core pole 30 and the left salient core pole 31 have a symmetrical shape and have three slots, so coking and torque unevenness are large to some extent. For example, in a symmetrical core with 3 slots @ on the core outer diameter 23, the effective total flux changes depending on the rotational position of the core. Fig. 5 shows the magnetic flux distribution when the core position is 0°, and Fig. 6 shows the magnetic flux distribution when the core position is 30°. shows. In FIGS. 5 and 6, 33 is a mug 2-/t, 34 is a frame,
35 is a magnetic flux distribution, and 36 is a core.

The effective total flux in Figure 5 is 3900 ma,
The maximum value is shown at 7 Maxwell, and the effective total flux in FIG. 6 shows the lowest value at 3500 Maxwell, and due to the change in this effective total flux, the coking torque has a large value of 1.7gc+a. In order to reduce coking and torque unevenness with 3 slots, it is common practice to add a skew when stacking the core, but this has the problem of complicating the process and increasing cost.

OBJECT OF THE INVENTION An object of the invention is to provide a small DC motor with low coking and low torque unevenness at low cost.

Composition of the Invention The present invention includes a plurality of core salient poles formed by slots, and a pair of protrusions that protrude from opposite slots on both sides at the tip of each core salient pole with different protrusion amounts. For example, a 3-slot core.

Therefore, the core salient pole takes on an asymmetrical shape, which reduces the number of slots and reduces coking and torque unevenness, as will be described later.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 to 3. That is, in this core, three core salient poles 2 are formed by slots l, a pair of protrusions 3.4 are protruded from the slots on both sides of the tips thereof, and the protrusions Na of the protrusions 3, 4 are
b is different.

The effective total flux of the core of this embodiment configured in this manner will be explained. Similar to the conventional configuration described above, the magnetic flux distribution diagram when the core has an outer diameter of 23n3 slots and the protrusion 3.4 of the core salient pole has an asymmetrical shape with a symmetry of 2.6 is shown below when the core position is 0°. In FIGS. 2 and 3, 5 is a magnet, 6 is a frame, 7 is a magnetic flux distribution, and 8 is a core. As a result of the measurement, when the core 8 position is Oo, the effective total flux is 3900mm, which shows the maximum value at kuswell, and when the core 8 is at 30', the effective total flux is 360mm.
It showed the lowest value of 0. As a result, the lowest value is 1 compared to the conventional core.
Due to the improved 00 Maxwell, the coking torque is as low as 1.3 gcm, which is a 23% improvement in coking torque compared to the conventional symmetrical core.

As described above, according to this embodiment, the coking torque is improved by 23% by making the shape of the salient pole portion of the 3-slot core into an asymmetrical core with a symmetry of 2.60.

Effects of the Invention As described above, according to the present invention, since the core salient pole is configured asymmetrically, excellent effects such as a small number of slots and small coking and torque unevenness can be obtained. This effect makes it possible to supply small-sized DC motors at low cost.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a three-slot core in an embodiment of the present invention, FIG. 2 is a magnetic flux distribution diagram at a core position of 0°, and FIG. 3 is a magnetic flux distribution diagram when the core is moved to a position of 30°. Fourth
The figure is a plan view of the conventional example, FIG. 5 is a magnetic flux distribution diagram at the core position 0°, and FIG. 6 is a magnetic flux distribution diagram when the core is moved to the 30' position.61...slot, 2... Core salient pole, 3
, 4... Protrusion, 8... Core Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A core for a small motor, comprising a plurality of core salient poles formed by slots, and a pair of protrusions that protrude from opposite slot sides on both sides at the tip of each core salient pole with different protrusion amounts.