JPH0363305B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for insulating and fixing an armature coil in a slot using thermofusible powder. For example, taking the rotary armature for a starter shown in Figure 1 as an example, in recent years the speed of automobiles has increased,
As devices become smaller and lighter, demands for load resistance such as centrifugal force and vibration have become stronger, and it has become necessary to impregnate the inside of the coils in the slot with a fixing material between the coils. Conventionally, in order to impart load-bearing properties to such armature coils, a method of impregnating them with a liquid mixture of liquid epoxy resin and an epoxy resin curing agent known as a solvent-free varnish has been particularly frequently practiced in recent years. The reason for this is that if the epoxy resin curing agent added to the liquid epoxy resin is appropriately selected, the curing speed can be increased and excellent adhesion between the coils can be obtained. However, this liquid epoxy resin mixture has problems such as the faster the curing speed, the shorter the usable life, and the inconvenience of handling the liquid epoxy resin mixture, which significantly reduces productivity. ing. Furthermore, this liquid epoxy mixture easily enters the inside of the slot when it is impregnated, but there is a problem in that it flows out from the slot when it is heated and hardened. Therefore, thermofusible powder, which has a long service life and is easy to handle, is used as a bonding material between the coils, but this thermofusible powder flows during curing, causing a sag phenomenon and forming a thin film. The paint film may become uneven. Further, it is necessary to cut and finish the excess coating film 6 adhering to the outer periphery of the iron core shown in FIG. 2, resulting in a problem that the process and work time are long. Furthermore, since the coil in the slot into which the armature coil is inserted has a small heat capacity, the amount of heat-fusible powder adhering to it is small, so the load bearing capacity is poor, and the coil often protrudes from the iron core during high-speed rotation. Therefore, as a result of various studies on the above-mentioned problems, the inventor of the present invention preheated the iron core containing the coil, coated the preheated coil with a heat-fusible powder by a fluidized dipping method or a spraying method, and coated the iron core in a molten state. While rotating, touch the belt and insert it inside the slot.
It was found that the problem could be solved by filling the mold with molten resin and then curing it while rotating. The heat-soluble powder used in the present invention includes epoxy, polyester, polyimide, acrylic, urethane,
There are all kinds of thermosetting resins such as esterimide, but among them, epoxy with a fast curing speed and high strength is effective, and one with good fluidity when melted has good impregnation into the coil. The armature coil of the present invention has a shape as shown in FIG. 1, and those with many slots are more effective in terms of working efficiency than those with fewer slots. In the figure, 1
is the commutator, 2 is the armature coil, 3 is the iron core,
4 is a slot portion, and 5 is a shaft. A method for fixing an armature coil according to the present invention will be explained with reference to the drawings.
Figure 4A shows the armature before resin coating. Figure B shows the product in a molten state after painting, and Figure C shows the product after filling the slot with molten resin according to the present invention, wiping off the excess resin from the outer periphery of the armature core, and then hardening it. FIGS. 5A, B, and C show cross-sectional views of the slot portion corresponding to FIGS. 4A, B, and C above. FIG. 6 shows a flow chart of the present invention. In FIG. 6, the armature is preheated at A;
B is powder coated with resin. (This figure shows the case of the scattering method.) At C, the resin is in a molten state.
At step D, the excess resin 6 applied to the outer periphery of the core is brought into contact with the outer periphery of the core and pressure is applied to fill the slot, and the excess resin is further wiped off and dropped. The details are shown in FIG. The directions of rotation of the armature and belt are opposite, the belt giving a rotation of 1-30 RPM and the armature giving a rotation of 50-200 RPM. Then, as shown in the figure, the excess resin is filled into the slot and wiped off.
Cured at E. Note that the mechanism for pressing the belt against the outer periphery of the iron core is omitted in FIGS. 6 and 7. And Figure 7A
is a bottom view and B is a side view. Coating methods used in this invention include generally known fluidized dipping methods, scattering methods, spraying methods, etc., and the spraying method or fluidized dipping method is effective. In the method of filling the inside of the slot with resin according to the present invention, as shown in FIG. 2 and FIG.
Apply. In this coated molten state, a belt is brought into contact with the outer periphery of the core and rotated while applying pressure, thereby filling the slot 4 shown in FIGS. 3 and 5C with the resin. In the present invention, after filling the inside of the slot with resin, the resin is heated and cured while being rotated. Preferably, if a powder that hardens quickly is used, it is preferably hardened while being rotated by the residual heat of the armature coil. The process of the present invention involves heating an armature coil in which a coil is wound around an iron core, coating it with thermosetting resin powder, melting the powder resin, and filling the inside of the slot with the resin that has adhered to the iron core in a molten state. and rotary harden. The present invention will be explained with examples. Comparative Example 1 Automotive starter armature preheated to 240°C (24 slots, 2 mm dent inside the slot)
A 2mm wide coil (2φ50 turns wound) was coated with epoxy powder Scotchicast No. 265 (Sumitomo 3M Co., Ltd.) using fluid dip coating and statically cured. Comparative example 2 Preheat the starter armature to 180℃,
Example 1 Same as Comparative Example 1, except that the starter armature was preheated to 240°C, and painted in the same manner as in Comparative Example 1. After coating, a Teflon coated (Teflon is a trade name) stainless steel with a width of 50 cm was applied. The belt was brought into contact with the outer circumferential surface of the starter armature, and the starter armature was rotated while the resin adhered to the starter armature in a molten state was press-filled into the slot and hardened by rotation. Example 2 The starter armature was preheated to 240° C., and Scotchicast No. 265 was sprinkled and applied while rotating, and then the same procedure as in Example 1 was carried out. The results of the above example are shown in the table.

[Table] From the above results, it is clear that according to the present invention, a high-performance product with a short cutting time and a high breaking rotation speed can be obtained.

[Brief explanation of drawings]

Figure 1 is a side view of a rotating electric machine for an automobile starter, Figure 2 is a cross-sectional view of a part of a conventional iron core showing the powder-coated iron core and the coils inside the core, and 6 is a powder-coated coating film. It is. FIG. 3 is a sectional view of a part of the iron core according to the present invention, FIG. 4 is a schematic flow diagram of the present invention, FIG. 5 is a sectional view of a slot corresponding to the flow of FIG. 4, and FIG. flowchart diagram,
FIG. 7 is a detailed view of filling the slot with resin using the belt. 1 is commutator, 2 is coil, 3 is iron core, 4
5 is a slot portion, 5 is a shaft, 6 is a resin, and 7 is a belt. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1 After heating the armature core with the armature coil housed in the slot to a temperature higher than the melting point of the thermosetting resin powder, the surfaces of the armature core and coil are powder coated with thermosetting resin powder. While the coating film formed on the armature core is in a molten state, the armature core is rotated and a belt is brought into contact with the outer periphery of the armature core to press and fill the coating film on the outer periphery of the armature core into the slot, and the filled coating film is transferred to an electric machine. A method for fixing an armature coil, which is characterized by hardening the child core while rotating it.