JPS5930026B2 - Manufacturing method for small motor rotor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method of manufacturing a rotor for a small motor.

A conventionally known method for manufacturing a rotor for a small motor will be explained with reference to FIG. 1. An iron core 1 is fitted onto a shaft 6 together with a commutator 1, and a required number of conductors are inserted into each slot portion 4 on the outer periphery of the iron core 1. At the same time, for products that require centrifugal force characteristics, the end of the conductor 3 is wrapped tightly with piano wire 10 through an insulating material 12, and the conductor 3 is insulated with a solvent-based insulating varnish that is liquid at room temperature. The end of the winding is either fixed by soldering 11 or tied directly to the conductor 3 with hemp thread or the like to insulate it.

In the above-mentioned rotor manufacturing process, the insulating varnish unexpectedly adheres to the outermost diameter part of the rotor during the above-mentioned insulation treatment, so the outer peripheral surface of the rotor may interfere with the inner peripheral surface of the stator. In order to prevent this, generally a step is taken in which the outermost diameter part of the iron core 1 is cut with a cutting tool or the like.

In this cutting process, when the production volume is relatively low, the cutting machine rotation speed and cutting speed can be kept low, so no abnormalities will occur. However, when the production volume increases, the cutting machine rotation speed and cutting speed may be extremely high. When productivity is increased, cutting burrs occur on the outermost diameter part of the iron core 1 during cutting, and if the cutting burrs remain in the product, there is a major problem that can lead to electrical failures such as short circuits between lines during operation. Ta.

The inventors of the present invention have conducted various experiments and research on how to prevent the occurrence of cutting burrs, and as a result, they have discovered a surprising fact.

In this process, an insulating impregnated fixing material is aggressively and thickly adhered to the entire outer circumference of the core, and when the outer circumferential surface of the core is cut together with this adhered insulating material, surprisingly, the boundary between the outer circumferential surface of the core and the slot is removed. There were almost no cutting burrs in the area.

Moreover, in order to actively and thickly adhere the insulation impregnating fixing material to the outer peripheral surface of the core, the conventional insulation varnish that is liquid at room temperature (e.g. liquid epoxy resin) is not satisfactory as the insulation impregnating fixing material. They also discovered that it was necessary to use a thermosetting resin that was in powder form at room temperature.

Therefore, the present invention is based on the above-mentioned experimental research results and aims to provide a method for manufacturing a rotor for a small motor in which almost no cutting burr occurs when cutting the outer periphery of an iron core.

The method for manufacturing a rotor of the present invention will be explained below with reference to the embodiments shown in the figures.

First, before explaining the present invention, the basic method of the present invention will be explained.

The rotor shown in FIG. 2 is a small motor rotor obtained by the basic method of the present invention, and the conductor 3 loaded in each slot portion 4 of the iron core 1 is used as an insulation impregnation fixing material during insulation impregnation treatment. Using an epoxy resin that is powdery at room temperature, for example, an epichlorohydrin type epoxy resin, the insulating impregnated fixing layer 2 is formed in the slot portion 4 to be thicker than the outermost diameter part of the iron core 1 and covers the entire outer circumferential surface of the iron core 1. 4), the outer circumferential surface of the iron core 1 is cut together with the resin adhered thereto, so that the outermost diameter part of the iron core 1 and the outermost diameter part of the insulating impregnated fixing layer 2 are cut into the core after cutting. Same as the outermost diameter of core 1 or plus 0,03 from the outermost diameter of core 1
The insulating impregnated fixing layer 2 is processed within the range of 2 mm - minus 0.055 mm.

That is, immediately after cutting, the outermost diameter part of the iron core 1 and the outermost diameter part of the insulating impregnated fixed layer 2 are the same as the outermost diameter part of the iron core 1, but
In general, powdered resin contains 0.3 to 0.8% water, and in a completely dry state and a saturated water absorption state, the expansion and contraction of the resin and the expansion coefficient of the iron core and the resin's Due to the difference in expansion coefficient, the insulation impregnated fixed layer 2 after cutting
According to experiments, the outermost diameter part of the iron core 1 fluctuates within a range of +0.0321n71L to -0.055mm from the outermost diameter part of the iron core 1.

Figure 3 shows that when the outermost diameter part of the iron core 1 and the insulating impregnated fixing layer 2 are the same, Figure 5 shows that the insulation impregnated fixing layer 2 has a lower diameter than the outermost diameter part of the iron core 1 due to expansion of the resin. Figure 6 shows the case where the insulation impregnated fixing layer 2 is 0.055 m1 thinner than the outermost diameter part of the iron core 1 due to resin contraction.

In addition, in FIGS. 3 to 6, 5 is a throttle surface insulating layer.

Accordingly, the main waist portion of the method of the present invention is as shown in FIG.

Figure 1 shows that the relationship between the iron core 1 and the insulating impregnated fixing layer 2* is particularly deep compared to Figures 3, 5, and 6. The amount is small and the gap B between the outermost diameter part of the iron core 1 and the smallest outer diameter part of the insulating impregnated fixing layer 2 in the throttle part 4 is 0.05, which is the dimension due to resin contraction.
In this case, in the insulating impregnated fixed layer 2 extending from the slot portion 4 of the iron core 1 to the outer peripheral surface, the input surface A and the cutting surface A' of the cutting blade are formed larger than 5 mm.
An excellent outer peripheral cutting effect can be obtained only when the thickness of the material is at least 0.2 mm or more.

The state shown in Fig. 7 is similar to the state shown in Fig. 4 due to uneven adhesion of the powder resin and flow during welding of the powder resin.
These are formed on the same iron core.

Next, to specifically explain the method of the present invention, the slot portion 4
An iron core 1 with an outer diameter of 48 mm and a length of 457 nm is fitted onto a shaft 6 with a diameter of 101 mm and a length of 198 mm, and a slot surface insulating layer made of epoxy resin with a thickness of 0.2 mm to 0.3 mm is attached to the iron core 1. 5 and as a conductor,
JISC3210 polyester copper wire display type 1 Po1y
After winding the wire using ether wire (diameter 1.8 mm) and connecting the end to the commutator 7 by soldering or melting crimping, the shaft 6
Mask only the entire winding section and commutator 7.
The entire outer periphery of the iron core 1 is impregnated and coated with an epoxy resin, including the connection portion of the iron core 1 to the outer peripheral surface of the iron core 1, thereby creating an insulating impregnated fixing layer 2 that is thicker than the outermost diameter part of the iron core 1, as shown in FIG.

In this case, in the same core 1, as shown in FIG.
As described above, there is a portion where the gap B between the resin and the minimum outer diameter portion is larger than the size due to the shrinkage of the resin.

The preparation conditions in this case are as follows.

Table 2 shows the results of actually cutting the outer periphery of the rotor obtained using Cloth 1 using a cutting machine and comparing it with a conventional product.

Table 3 shows the conventional liquid epoxy resin treatment using a high-speed cutting machine and the one obtained by the present invention by changing the rotational speed of the high-speed cutting machine and the cutting speed for cutting the outermost diameter part of the iron core 1. This is the result.

As is clear from the above results, when cutting the outermost diameter part of the iron core 1 of the rotor obtained by the present invention, cutting can be done five times faster than the conventional insulation impregnation fixing process, and automation is possible. This greatly contributes to faster speeds.

In particular, in order to obtain the best cutting conditions, it goes without saying that the insulating impregnated fixed layer 2 should be made thicker than the outermost diameter part of the core 1, and the insulating impregnated fixing layer 2 should be made thicker than the outermost diameter part of the core 1 with the cutting diameter. A remarkable effect was produced in the portion where the outermost diameter portion of the fixed layer 2 was thickened within the same 0.032 mm.

A dimension of about 0.032 mm is almost average when visually observed, but can be clearly determined when measured with a precision measuring tool.

Although it varies slightly depending on the resin material, type of hardening agent, type and amount of filler material added, curing time, etc., after cutting it is approximately +0.032 to -0.0 based on the outermost diameter part of the iron core 1.
Good results were obtained in the area where the insulating impregnated fixing layer 2 was present within a range of 55 mm.

In particular, the cutting blade is applied to a portion where the gap B between the outer circumferential surface of the iron core 1 and the minimum outer diameter of the insulating impregnated fixing layer 2 inside the slot portion 5 is larger than the size due to shrinkage of the resin, for example, a portion where this gap B is about 2 mm. The contact surface and the surface through which the cutting blade cuts must have at least 0.2 mm of insulating adhesive material adhered to the surface.

That is, in the portion where the gap B in FIG. 7 is larger than the size caused by the shrinkage l of the resin, the input surface A of the cutting blade is
The thickness of the cutout surface A' greatly influences the cutting condition.

According to the experimental results, when the thickness of the input surface A and the cut-out surface A' was 0.15y+cy+t, no occurrence of cutting burrs was observed under the conventional cutting conditions of 150 Orpm and 22 seconds. Under the high-speed cutting conditions of 180 rpm and 10 seconds, some cutting burrs were observed.

On the other hand, if the thickness of the input surface A and the cut-through surface A' is set to 0.2 mm or more, even under the above-mentioned high-speed cutting conditions, there will be no cutting burrs that can cause defects in the product, and a good cutting condition can be achieved. Obtained.

As described above, in the present invention, an epoxy resin that is powdered at room temperature is used as the insulation impregnation fixing material, and this resin is adhered to the outer peripheral surface of the iron core, and the insulation impregnation fixation is carried out in each slot of the iron core. The layer has a portion where the minimum outer diameter is smaller than the outer diameter of the core, and the input surface and the cutting surface of the cutting blade with respect to the core in this portion have at least 0.0 mm.
Since the resin is adhered to a thickness of 2 mm and the outer circumferential surface of the core is cut, even if the insulation impregnated fixing layer of the core slot is extremely recessed than the outer circumferential surface of the core, it can be cut under high-speed cutting conditions. This has the excellent effect of preventing cutting burrs from occurring at the boundary between the outer circumferential surface of the core and the slots, and making it possible to obtain a high-quality rotor with high efficiency.

[Brief explanation of the drawing]

FIG. 1 is a side view showing the rotor of a conventional small motor, and FIGS. 2 to 6 are for explaining the basics of the method of the present invention. Figures 3, 5 and 6 are side views showing the manufactured rotor; Figures 3, 5 and 6 are enlarged sectional views showing the slot portions of the rotor shown in Figure 2; Figure 4 is the outermost diameter of the core before cutting the outer periphery of the core. FIG. 7 is an enlarged sectional view showing a state in which the insulating impregnated fixing layer is thickly coated on the core, and is used to explain the method of the present invention. FIG. 3 is an enlarged cross-sectional view of the main parts showing a state in which the method of the present invention is applied to a rotor. 1... Iron core, 2... Insulating impregnated fixing layer,
3...Conductor, 4...Slot part, 5...
...Slot surface insulating layer, A, A'...
・Resin thickness at the input surface and cutting surface of the cutting blade,
B: Gap between the outer peripheral surface of the core and the minimum outer diameter surface of the insulating impregnated fixed layer in the slot.

Claims (1)

[Claims] 1 In a device in which a plurality of conductors are loaded into each slot on the outer periphery of the core and an insulating impregnated fixing material is impregnated between these conductors to insulate and fix the conductors to each other and between the conductor and the iron core, the insulating impregnated fixing material is Powdered epoxy resin is used to adhere this resin to the outer circumferential surface of the core, and each slot has a portion where the minimum outer diameter of the insulating impregnated fixing layer is smaller than the outer diameter of the core. A method for manufacturing a rotor for a small motor, characterized in that the resin is adhered to a thickness of at least 0.2 mm on an input surface and a cutting surface of a cutting blade with respect to the iron core, and the outer peripheral surface of the iron core is cut. .