JPS62196053A - Manufacture of molded stator - Google Patents

Abstract

PURPOSE:To improve motor characteristics and prevent generation of vibration and noise by injecting molded resin from gates which are provided in a plurality of symmetrical positions in the manner of bordering the end face of a stator core. CONSTITUTION:A molded stator is manufactured by means of a lower tool 24 and an upper tool 25 on the basis of a stator core 22 installed in a state where a coil 21 is wound around a bobbin 23. These tools 24, 25 are furnished with salient cores 26, 27 at their central parts respectively and also equipped with gates 29-32 and a molded resin-injecting pot 34. These gates 29-32 are respectively provided in symmetrical positions so that two gates or more will border the end face of the stator core 22. As a result, the pressure of molded resin injected from the gates 29-32 is symmetrically applied to a plurality of portions of the end face of the stator core 22, said core 22 does not deviate eccentrically also from bearing device-fitting portions 41, 42 and generation of vibration and noise can be prevented too.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing a molded stator by injection molding.

(Prior Art) Conventionally, there have been molded stators for motors, which are made by covering a stator core and a coil wound around the stator core with a molded layer of molded resin, and injection molding is generally used to manufacture the stator. There is. FIG. 4 shows how such a molded stator is manufactured by the injection molding method. In the figure, 1 is a coil, 2 is a stator core equipped with the coil 1 wound around a bobbin 3, This stator core 2 is first housed inside the lower mold 4 while fitting into a protruding core portion 5 provided at the center of the lower mold 4.
It is received by a stepped portion 6 provided at the intermediate portion of the protruding core portion 5 . Next, the upper mold 7, that is, the upper mold 7, is fitted to the lower mold 4 so that the protruding core part 8 provided at the center of the mold abuts the protruding core part 5 and the entire upper coil end portion of the coil 2 is covered. As a result, the stator core 2 and coil 1 are set inside the mold 9 consisting of the upper mold 7 and the lower mold 4. And then those upper mold 7 and lower mold 4
Gate 10 installed at one location (on the right side in the figure) of the mating part of
Molten resin is injected into the mold 9 to form a mold layer 11 covering the stator core 2 and coils 1.

(Problems to be Solved by the Invention) In the above-mentioned device, when the molten mold resin is injected from the gate 10, the stator core 2 is pushed by the injection pressure, and the stator core 2 is not supported by the pressure. Since there is a gap in the center part of the lower die 4 where it fits with the protruding core part 5 due to the dimensional allowance for fitting and detaching, the fitting of the bearing device may be uneven or tilted accordingly. The air gap between the motor and the rotor (not shown), which is eccentric with respect to the portion 12, 13, becomes uneven, causing problems such as deterioration of motor characteristics and generation of vibration and noise. Also, in this case, there is one gate 10, and this one gate 10
Since the molten mold resin is injected from the beginning, there is a problem that it takes a long time to complete the injection.Furthermore, the injection lacks uniformity, and the flow of the injected molten resin is not good. Because of this, there was a problem of poor moldability. In addition, the injection pressure must be increased for this reason, and the large injection pressure damages the coil 1, resulting in a problem that layer short-circuits and disconnections are likely to occur.

Therefore, an object of the present invention is to be able to mold a mold layer that covers the stator core and coils without causing the stator core to shift or tilt, to quickly and with good moldability, and without the risk of layer short-circuiting or wire breakage of the coils. The purpose of the present invention is to provide an excellent molded stator manufacturing method.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides gates that are provided at a plurality of symmetrical positions so as to face the end face of the stator set in the mold, and that gates are provided at a plurality of symmetrical positions so as to face the end face of the stator core set in the mold, and the gates are provided at positions facing the gates on the end face of the stator core. The molten molding resin is injected by forming holes penetrating from at least one of the two symmetrical positions to the opposite end faces, respectively.

(Function) According to the present invention of the above means, the injection pressure of the molten resin is applied symmetrically to a plurality of locations on the stator core,
In addition, a larger amount is injected per unit time than before, and in addition, it is injected not only to the end face of the stator core facing the gate, but also to the opposite end face through the hole in the stator core. The injection pressure can also be kept low.

(Example) Examples of the present invention will be described below with reference to FIGS. 1 to 3.

First, in the first embodiment shown in FIGS. 1 and 2, 21
is a coil, and 22 is a stator core in which the coil 21 is wound around a bobbin 23. On the other hand, 2
4 is the lower mold, 25 is the upper mold, and each has a protruding core portion 26.2 in the center.
7, the protruding core portion 26 of the lower die 24 is provided with a stepped portion 28 at the intermediate portion. Reference numerals 29 to 32 are gates, which are connected to the upper mold 25 from above to the inside of the upper mold 25 and further to the inside of the mold 33 consisting of the upper mold 25 and the lower mold 24; 3
0 is on one diagonal of the mold 33, and the gate 31
and the gate 32 are arranged symmetrically on the other diagonal of the mold 33. 34 is a pot for injecting a molding resin provided above the upper mold 25 so as to commonly face all of the gates 29 to 32, and 35 is a piston. On the other hand, 36 to 39 are the stator core 2
Holes are formed in the four corners of the stator core 22 so as to penetrate from one end surface to the other end surface of the stator core 22. When the stator core 22 is set in the mold 33 as described later, the holes 36 to 39, the above gates 29 to 3
I am trying to make sure that each of the 2 is present one by one. In particular, in this embodiment, the cross-sectional area of the tips of the gates 29-32 is set larger than the cross-sectional area of each of the holes 36-39.

Now, in manufacturing a molded stator based on the above configuration, first, the stator core 2 on which the coil 21 is installed is
2 is accommodated in the lower mold 24 while fitting into the protruding core portion 26 of the lower mold 24, and is received by the stepped portion 28. Next, the lower mold 24 containing the stay core 22 and the coil 21 is advanced toward the upper mold 25 and combined with the upper mold 25, thereby setting the stay core 22 and the coil 21 inside the mold 33. Here, in that set state, the gate 29
32 face one end face of the stator core 22, and further face the holes 36 to 39 one by one.

Thereafter, the molten resin stored in the bot 34 is pushed out by the piston 35 and injected into the mold 33 through the gates 29 to 32, respectively. As a result, the mold layer 40 covering the stay core 22 and the coil 21 is molded, and a molded stator is manufactured, which is then taken out.

In carrying out the manufacturing method described above, a plurality of gates 29 to 32 are provided at symmetrical positions so as to face the end surface of the stator core 22, so that the pressure of the mold resin injected from the gates 29 to 32 is reduced. The bearing device fitting portions 41, 42 are applied symmetrically to multiple locations on the end face of the stator core 22, and are not applied in a biased manner as in the conventional case, so that the stator core 22 is not biased or tilted. However, the stator core 22 is not eccentric, and the air gap between it and the rotor (not shown) can be made uniform, so that the characteristics of the motor can be improved, and the generation of vibration and noise can be prevented. Furthermore, since the mold resin is injected from the plurality of gates 29 to 32 mentioned above, the amount of injection per unit time can be increased compared to the conventional injection from one gate, and therefore the injection can be carried out in a short time. The process can be completed and the required time can be shortened. Moreover, the mold resin injected from the gates 29 to 32 spreads at one end surface of the stator core 22, and at the same time passes through the holes 36 to 39 to reach the other end surface of the stator core 22. However, since it has the same spread, it can be poured uniformly over the entire surface, and the flow of the molten metal can also be improved, improving moldability. In addition, due to these factors, the injection pressure of the molding resin can be kept low, and therefore, problems such as disconnection of the coil 21 and layer shorts caused by the injection pressure can be prevented, improving reliability. can be achieved.

Here, FIG. 3 shows a second embodiment of the present invention,
In this case, two symmetrical positions of one of the locations facing the gates 29 to 32 of the stator core 22, in this case, the tube location facing the gate 29.30, are attached to the opposite end surface with a larger size than the gates 29.30. Hole 43.44 passing through
, and no holes are formed in the areas facing the other gates 31 and 32. If this is done,
The mold resin injected from the gates 31 and 32 spreads on one end surface of the stator core 22, and the mold resin injected from the gates 29 and 30 passes through the holes 43 and 44 and spreads on the opposite end surface of the stator core 22. However, it is basically the same as the first embodiment described above, and therefore the same effect as that of the first embodiment can be obtained. I can do it.

In addition, the present invention is not limited to the embodiments described above and shown in the drawings (in particular, the specific numbers of holes in the gate and the stator core may be changed as appropriate without departing from the scope of the invention). It can be implemented by

[Effects of the Invention] As is clear from the above description, according to the present invention, the mold resin can be injected through the gates provided at order-symmetrical positions so as to face the end face of the stator core, so that the stator core does not shift or tilt. Therefore, the characteristics of the motor can be improved, vibration and noise generation can be prevented, and the injection can be completed in a short time. Since the molding resin can be injected into the opposite end face in the same way, the molding resin can be injected evenly and with good flow to achieve good moldability, and in addition, the injection pressure can be kept low. Therefore, various excellent effects such as prevention of problems such as coil disconnection and layer short circuit are achieved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a mold stator and its molding die in the first embodiment of the method of the present invention, and FIG. 2 is a cross-sectional view of FIG.
3 is a view corresponding to FIG. 1 in the second embodiment of the method of the present invention, and FIG. 4 is a view equivalent to FIG. 2 in the conventional method. In the figure, 21 is a coil, 22 is a stator core, 29 to 3
2 is a gate, 33 is a mold, 36 to 39 are holes, 40 is a mold layer, and 43.44 is a hole.

Claims (1)

[Claims] 1. A stator core wrapped with coils is set in a mold, and molten mold resin is injected through a gate leading into the mold to form a mold layer covering the stator core and coils. , the gates are provided at a plurality of symmetrical positions so as to face the end face of the stator core, and holes are provided that penetrate from at least two symmetrical positions of at least one of the places on the end face of the stator core facing the gates to the opposite end face, respectively. A method for manufacturing a molded stator, characterized in that the molded stator is formed and then the molten resin is injected.