JPS62207161A - Structure of iron core for dc slot-less core motor - Google Patents

Abstract

PURPOSE:To improve iron loss and saturation magnetic flux density, and to reduce cost by using a sintering material consisting of a silicon steel at a specified ratio as a core material and forming cores divided in the radial direction and the thrust direction by the material. CONSTITUTION:A core 1 is divided into two in the radial direction, and constituted by fixing split pieces 2, 3 by adhesives. A sintering material composed of 3-10wt% silicon steel (an Fe-Si alloy) is employed as a core material. Silicon is weight distribution of 7wt% is added to iron such as pure iron powder in a shape such as the substance of ferrosilicon or silicon powder, and raw material powder to which a substance such as 1wt% zinc stearate is added and mixed is used as a molding assist.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to the structure of an iron core of a high-torque DC slotless core motor (hereinafter referred to as a flat motor).
It is widely used as a drive motor for various functional devices for automobiles.

(Prior art) As a prior art related to the present invention, Japanese Patent Application Laid-Open No. 59-70174
There is a technique disclosed in the publication of Brushless Morph J, a superimposed type in which armature coil groups do not overlap.

This device has a structure in which a winding is applied to the surface of the iron core, and magnetic flux is generated by two pairs of magnetic poles from above and below.The iron core is a yoke that passes the magnetic flux, and when this rotates or the magnetic poles rotate, it operates as a motor. It is something to do.

(Problems to be Solved by the Invention) The magnetic poles of the motor are usually 2P (P=1 to N) pole pairs (N
-3), when the iron core or magnetic pole rotates once, an alternating magnetic flux with a 2P period acts on the iron core from above and below. There is an interlayer point where heat loss due to overcurrent occurs due to the addition of alternating magnetic flux of r=2PR/60 (H2). (2) Since the iron core is a yoke that passes magnetic flux, the saturation magnetic flux density (Bs) The higher the value, the thinner the iron core and even the thinner the motor.

The required characteristics for an iron core are a small iron loss from (1) above, and a high Bs from (2). Among existing materials, materials with small iron loss are materials with high resistivity ρ, and such The material has a small Bs, which inevitably results in a thick core, and a material with a high Bs has a small resistivity ρ, which causes a large heat loss due to overcurrent, resulting in a significant decrease in the efficiency of the remoter.

Pure iron and silicon steel (3% Si) are used as core materials.

There are Fe-Ni alloy Permalloy and Mn-Znn Fushii (.), and a comparison of iron loss, Bs, and cost for these is shown in Table 1.

Table 1 From Table 1, all of the above materials are not very good in terms of evaluation when used as the iron core of a motor.

The technical object of the present invention is to provide an iron core structure for a flat motor that is favorable in terms of the above-mentioned iron loss, BS, cost, etc.

[Structure of the invention]

(Means for solving the problems) The technical means taken to solve the above technical problems are as follows. In other words, in a flat motor with an iron core sandwiched between magnetic poles for the purpose of thinness and high torque, 3 to 10 wL% silicon glib (Fe-
The flat motor has a structure in which a disk is formed from a sintered material made of Si alloy), and the disk uses an iron core divided in the radial direction and the thrust direction with respect to the rotating shaft.

(Operation) The above technical means operates as follows. That is, <1) Regarding the low range of iron loss when silicon is added to pure iron, the relationship between iron loss (W) and frequency (82) is shown in FIG. In Figure 1, A has a Si content of 0% and B has a Si content of 1w.
t%, C is 3wt%, D is 4wt%, E is 7wt%, F
is 19 wt%, and as the addition of silicon increases, the resistivity ρ increases, and the resistivity ρ increases from 45.8 (W) to 6.1 (W) for the (7 wt% Si) shown in the graph of E. It is intended to reduce (Bm=1.5 (T).

f=100Hz) (2) Coercive force Hc and magnetic permeability μm are improved by adding silicon, and the relationship between the amount of silicon added and magnetic properties is shown in FIG. From Figure 2, 7wt%
If the magnetic permeability of Si increases and the coercive force decreases, hysteresis loss will be greatly reduced. (Bm=
1.5 (T) DC) (3) Figure 3 shows the relationship between iron loss and frequency when an iron core containing 7% silicon is divided and laminated.

J is a graph of no division, K is a graph of 2 divisions, and L is a graph of 4 divisions.The iron loss when the core is divided and laminated is 1st.
The pure sintered body shown in the figure has a weight of 45.8 (W), but the 7wt% Si shown at the bottom of the figure is 0.6 (W), a reduction of about 98%. (Bm=1.5 (T), F=100Hz)
(4) By using a sintered material for the iron core, it is easy to form the shape by sintering, and there is no need for secondary processing.

(Example) Examples will be described below.

In Fig. 4, 1 is an iron core divided into two parts in the radial direction as shown in 2 and 3, and the divided pieces 2 and 3 are stuck together with adhesive, and the disc (iron core) 4 in Fig. The upper outer ring 5. is made by integrating four parts.
The upper inner ring 6, the lower outer ring 7, and the lower inner ring 8 are divided in the radial direction and the thrust direction with respect to the rotating shaft 10, and are integrated into one body.

The iron core is made of a sintered body of Fe-3L alloy, and 7wt% of silicon is added to pure iron powder (#200 under, atomized powder) in the form of ferrosilicon or silicon powder, and a forming aid is added. 1 wt % of zinc stearate was added as an agent and mixed to prepare a raw material powder.

After compression molding this powder at 7 T ON/cnl, the auxiliary agent was released at 600°C for 0.5 hours in a vacuum or reducing atmosphere, and then sintered at 1200°C for 2 hours to obtain a 7wt.
%, an iron core of 5i-Fe alloy was manufactured.

Figure 2 shows the DC magnetic characteristics of this core. G is the magnetic flux density and 3i quantity, H is the maximum magnetic permeability and 5i (ffill is a graph showing the relationship between coercive force and Sil, G7°H7+ 1
7 indicates a state of 7% Si.
・ In this case, the coercive force He is 27 (stone e) of pure iron,
As shown in Figure 7, the magnetic permeability μm increases to 0.68 (e) to 3680 = H7 = 8330 as shown in the H graph, and therefore the hysteresis loss is reduced by approximately 76% compared to pure iron. effective.

As shown in Fig. 6, if the iron core 4 of 7% 5t-Fe alloy is placed inside the magnetic poles 9a and 9b, and the gap between the iron core 4 and the magnetic pole 9 is lla and llb, the gap magnetic flux density is 2500G.
(The maximum magnetic flux density in the thickness direction is 15,000 G).The core loss value was measured by changing the alternating frequency, and the results are shown in FIG.

The iron loss of a core containing 7% Si is approximately 1/10 that of pure iron due to the improvement in resistivity associated with the addition of silicon, but the required iron loss value needs to be further reduced.
By performing the division as shown in the figure, the iron loss was further reduced to 0.6 W at an alternating frequency of 100 Hz.

This is shown in the box graph of FIG.

Furthermore, as a dividing method, it is effective to divide the magnetic flux flow in the core in both the thrust direction (thickness direction) and the radial direction (radial direction), as shown in FIG.

Also, if this iron loss value is achieved with other St% materials, 3
%Si results in 16 divisions, 5% results in 8 divisions, and as the amount of Si increases, the number of divisions to obtain the same iron m value decreases.

FIG. 8 shows the iron core divided into four parts wound with wires, and FIG. 9 is a wiring diagram thereof. 20 is a copper wire wound around an iron core, 21 and 22 are N-3 magnets, 23 is a commutator, and 24 is a brush. The number of turns is 12 around the circumference.
It is divided into equal parts and connected through a commutator, and in order to obtain high torque with a flat motor, toroidal winding is suitable because it can effectively connect the coils above and below the iron core to torque. Furthermore, the gap with the magnet can also be reduced.

〔Effect of the invention〕

The present invention has the following unique effects. In other words, in order to satisfy the required characteristics using conventional materials, it can also be achieved by separately laminating silicon steel plates (3% Si) as shown in Figure 3, but in this case the resistivity ρ is 45 ( μΩ・am), and it is necessary to increase the number of divisions in order to reduce iron loss, which increases the cost when forming the core.However, the present invention increases the resistivity by adding more silicon. At the same time, the magnetic properties are improved, and the required properties can be satisfied with a smaller number of divisions.Therefore, the iron core of the motor can be sintered, and the cost can be significantly reduced due to the reduction in man-hours during assembly and molding.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between iron loss and frequency depending on the amount of silicon added, and Figure 2 shows the relationship between the amount of silicon added and magnetic flux density, magnetic permeability,
It is a graph of the relationship with coercive force. Figure 3 is a graph of the relationship between iron m and frequency when the core is divided into two. Figure 4 is an explanatory diagram of the division of the core into two. FIG. 5 is a cross-sectional view divided into four parts, FIG. 6 is a cross-sectional view of the iron core fixed to the rotating shaft and installed inside the magnetic pole, and FIG. 7 is a cross-sectional view. is an explanatory diagram of magnetic field lines flowing through the iron core,
(A) is an explanatory diagram of the flow in the vertical direction, (B) is an explanatory diagram of the flow in the horizontal direction, and (C) is an explanatory diagram of the flow of magnetic lines of force as seen from the perspective direction of the iron core. 9 is a perspective view of the iron core of this embodiment with wires wound thereon, and FIG. 9 is a developed view of the windings. 1.4... Iron core

Claims (1)

[Claims] In the rotating rotor with the iron core sandwiched between the magnetic poles of the DC slotless core motor, 3 to 10 wt% as the iron core material.
An iron core structure for a DC slotless core motor, in which a disk is formed from a sintered material made of an iron-silicon alloy, and the disk is divided into radial and thrust directions with respect to the motor rotation axis.