JPH0421421B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a molded motor in which a split core is subjected to toroidal winding and then its outer periphery is molded with molded resin.

Conventional structure and its problems If a toroidal winding is applied to the yoke of each slot of the annular core, the coil end dimensions can be shortened and a thin motor can be obtained. However, winding the annular core requires the use of a toroidal winding machine, which is not suitable for mass production and is therefore not a preferred method.
Therefore, a method suitable for mass production would be to divide the annular core in the radial direction, wind the wires on the yoke of each slot of the divided core using a flyer-type high-speed winding machine, and then join the divided cores together. It is valid. On the other hand, the windings are attached to the outer circumference of the core where the windings are applied to the core yoke, making it difficult to attach a frame and assemble the motor as in the past. A method is used in which the frame is integrally formed by molding the coil with a molded resin.

FIG. 1 shows a sectional view of a conventional molded motor in which a split core is wound and then molded.
In the figure, reference numeral 1 indicates a split core in which only the split surfaces 1a are butted together, 2 is a winding wound around a yoke for each slot of the split core 1, and 3 is a housing made of molded resin.

In the above configuration, in order to reduce the motor outer diameter (housing outer diameter), the smaller the resin thickness t ₁ covering the winding 2 is, the better; however, in order to maintain the joint strength of the dividing surface 1a, it is There is a paradox that the larger t ₂ is, the better. If t ₂ is not large enough, there is a risk of cracking due to heat shock after molding.

On the other hand, as a method to obtain the joint strength of the iron core without using resin, it is possible to provide uneven parts 1b on the dividing surface 1a of the iron core and engage them as shown in Fig. 2, but in the case of a small iron core such as a small motor, This is a method that cannot be adopted in reality. Another method is to provide a protrusion 1c on the core dividing surface and weld the tip of the protrusion 1c as shown in Figure 3, but in this case welding is done after the winding is completed, so there is no damage to the winding 2 during welding. Therefore, it is necessary to set the height h of the protrusion to be larger than the thickness _t3 of the winding 2. Therefore, the thickness _t4 of the molding resin at that portion becomes smaller, and there is a risk that cracks may occur in this portion due to heat shock after molding is completed. Furthermore, it is conceivable that the flow of resin is obstructed in this part during molding, and unnecessary resin molding pressure is applied to the winding part, leading to a decrease in quality.

OBJECTS OF THE INVENTION The present invention aims to solve the problems of the above-mentioned conventional examples and to improve the strength of a molded motor in which a split core with windings is molded.

Structure of the Invention The present invention makes the outer circumferential shape during molding a non-circular shape, such as an ellipse, and places the portion that requires strength of the molding resin on the long diameter portion, thereby reducing the wall thickness of that portion. The goal is to make it bigger.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to FIGS. 4 and 5. FIG. 4 shows a case where the invention is applied to the core structure shown in FIG. 1, and FIG. 5 shows a case where it is applied to the iron core structure shown in FIG. 3. As shown in the figure, the outer circumferential shape after molding is formed into an ellipse or an ellipse, the short axis is the minimum length necessary for insulation and frame construction, and the long axis is the minimum length necessary for reinforcing the dividing surface 1a or for resisting heat shock. Make the length to ensure wall thickness.

Then, parts that require reinforcement and wall thickness are placed in this long diameter part and molded.

Effects of the Invention As is clear from the above configuration, according to the present invention, the following effects can be obtained.

Even in molds where the core split surfaces are simply butted together without being joined by welding, dovetails, etc., the mold thickness is sufficient to reinforce the split surface joints, and the amount of resin used is greatly increased. You can get it without getting it.

For those with protrusions in the outer circumferential direction on the core dividing surface, it is possible to prevent the resin thickness from decreasing due to the protrusions, and to ensure a sufficient flow path for the resin. Molded products with stable quality can be obtained without applying excessive molding pressure.

Since the outer circumferential shape is no longer circular, the finished product will not roll during handling, making it easier to handle on the production line.

[Brief explanation of drawings]

1 to 3 are cross-sectional views of a stator of a conventional molded motor with toroidal windings, FIG. 4 is a cross-sectional view of a stator of a molded motor according to an embodiment of the present invention, and FIG. 5 is a cross-sectional view of a stator of a molded motor according to an embodiment of the present invention. FIG. 3 is a cross-sectional view according to another embodiment of the invention. 1... Split core, 1a... Split surface, 2... Winding wire, 3... Housing.

Claims (1)

[Claims] 1. A toroidal winding is applied to the yoke of each slot of the split core, which is divided into two parts, and the split core and the winding are integrally molded with mold resin with the split surfaces in close contact with each other. A molded motor in which the cross-sectional outer circumferential shape of the housing made of molded resin is approximately oval, and the closely spaced portions of the split surfaces of the split iron core are arranged so as to match the long diameter direction of the substantially oval.