JPH02155451A - Forming method for synthetic resin-sealed motor - Google Patents

Abstract

PURPOSE:To prevent improper insulation, deterioration of water resistance by filling resin in a mold, and then intermittently applying a molding pressure in the mold at a predetermined time interval. CONSTITUTION:When resin 5 is filled in a cavity of a mold, a winding gap 20 is contracted to be reduced, and the resin 5 is not impregnated into the interior. Here, if a molding pressure is temporarily reduced, a winding 3 is expanded to be increased in its winding gap 20 by its elasticity to improve its impregnation of the resin 5. However, since the molding pressure is low, even if the winding gap 20 is large, the resin 5 is not impregnated into the interior. Then, when the molding pressure is again applied, the winding 3 is contracted, but the region 5 impregnated into the winding gap 20 is intruded into the winding gap 20 due to the relationship of the pressure difference in a step of contracting the winding gap 20. Thus, when the molding pressure is intermittently applied, the region 5 can be impregnated into the narrow gap 20 by utilizing the contraction and expansion of the winding gap 20. In this manner, a product having excellent moisture resistance and voltage resistance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molding method in which a stator of an electric motor is placed in a mold and a synthetic resin is injected into the stator to seal the electric motor.

[Conventional technology]

FIG. 5 is a longitudinal sectional view showing a conventional method of molding a synthetic resin-sealed electric motor, as disclosed in, for example, Japanese Patent Laid-Open No. 53-121102.

In the figure, (1) is a mold that is divided into two parts, with a hollow space (1a
) and communicates with the outside through a gate (1b).

(2) is the stator core of the motor placed in the space (1a), (3) is the winding wound around the stator core (2), (4
1 is an injection molding machine, C5) is an injection molding machine (4) with a blank space (1
a) Synthetic resin injected inside.

A conventional molding method for a synthetic resin-sealed electric motor is configured as described above, and the molding operation is performed in a zero-order manner.

First, the mold (11) is heated to a temperature at which the resin (5) hardens, placed in the entire cavity (1a) of the stator core (2) to be sealed, and the mold (x) ff: is clamped. , resin +51 i
f For example, calcium carbonate,
Ta such as glass chops, fiber materials, and other inorganic fillers are mixed in at a total volume of about 50%.

Using the equipment and materials configured in this way, the stator core (
2) into the cavity (1a) of the mold (1) in which the resin (5) is placed, 20 g of the resin (5) is injected through the gate (1b) by the injection molding machine (4) at a high injection pressure of tookg/me2. Inject at a speed of around 1/sec. In this way, the electric motor is sealed with resin (5).

[Problem to be solved by the invention]

In the conventional molding method for a synthetic resin-sealed electric motor configured as described above, a large amount of inorganic filler is added to the resin (5) in order to improve cracking, insulation, tracking resistance, moldability, etc. Since the resin (5) is mixed in, the viscosity naturally increases and the resin (5) is not impregnated into the narrow gap between the zero windings (3) due to lack of fluidity.

There are problems such as poor insulation and deterioration of water resistance.

This invention was made to solve the above-mentioned problems, and it is a synthetic resin seal that can impregnate resin even in extremely narrow gaps between windings, making it possible to manufacture electric motors with excellent insulation, water resistance, etc. The purpose of the present invention is to provide a method for forming a stop motor.

[Means for Solving the Problems] The method for molding a synthetic resin-sealed electric motor according to the present invention involves lowering the molding pressure when the mold is filled with resin, and applying pressure again after leaving the mold for a certain period of time. This process is repeated until it hardens.

[Effect]

In this invention, since the molding pressure is intermittent at regular intervals after the mold is filled with resin, the gap between the windings, etc. expands due to elasticity due to fluctuations in the molding pressure, and contracts due to the molding pressure. As a result, even narrow winding gaps are impregnated with resin.

〔Example〕

Figures 1 to 4 are diagrams showing one embodiment of this invention.
The figure is a perspective view of the stator of an outer rotor type DC brushless motor, FIG. 2 is a sectional view taken along the line n--n of FIG. 1, and FIGS. Portions similar to those of the conventional device are designated by the same reference numerals.

In the figure, (2) is the stator core, which is formed by laminating multiple silicon steel plates.The first winding (3) has an upper insulation cover (Ill) and a lower insulation cover (Ill) to insulate it from the stator core (2). Approximately 20 wires with a diameter of about 50 microns are passed through SKY PerfecTV 03.
It has been wound 00 times. a3 is L5X10 cIIL that occurs at the joint of upper and lower inscapers αB and α■
ff41 is the core gap of several microns between the laminated surfaces of the silicon steel plates of the stator core (2), α
This is a commutating pole configured similarly to the stator core (2), ae
071 is a cylindrical bearing into which the rotating shaft of a rotor (not shown) is inserted, which is placed outside the stator core (2);
is a board consisting of an insulating plate fixed to the bearing αG, 0IS
A plurality of electronic components are attached to the Fi board αη to control the rotational speed, etc., ff9 is a plurality of lead wires connected to the winding (3) and supplied with power, and cXJt- is the winding (3). This is the gap between the windings. In addition, resin (
As for 5).

Inorganic filler is mixed into epoxy resin, etc.

A low-viscosity material that flows at room temperature before curing is used.

In the method for molding the synthetic resin-sealed electric motor configured as described above, a two-part molding die (see Figure 5) that has been attached to a press in advance is heated to around 130C, and the electric motor is placed inside the mold cavity. After placing the stator core (2) and clamping the mold using a press.

Prepare for injection of resin (5). At this time, the resin (5) is to be impregnated in the details of the first winding gap.

It is desirable that the inside of the mold cavity is once evacuated to 5 Torr or less using a vacuum pump (not shown) to degas the air in the gap between one winding and then injected. Then, after vacuuming, the resin +51f! : Inject into the mold at a pressure of 20 kg/CWL. Until the resin (5) fills the mold, only a low pressure is applied to the first winding (3), and as shown in Figure 3, the winding gap ■ is wide open, and the resin (5) is impregnated with metal. It's in easy condition. However, when the mold is filled with resin +51, a molding pressure of 20 kg/cm2 is applied directly to the winding (3), and as shown in Figure 4, the winding gap (2G) is compressed by the pressure, and when there is no pressure, It is smaller compared to resin (5
), like general liquids, the higher the pressure and the larger the gap, the better the fluidity, and it is desirable to mold at as high a pressure as possible. However, like 3 windings (3),
For molded products whose gap ■ changes due to external pressure, if the molding pressure is increased, the gap between each winding ■ changes due to the above reasons.
cannot be sufficiently impregnated with resin (5). This kind of phenomenon.

The same problem occurs in cover gap 0 and core gap I.

The moisture resistance and voltage resistance of the product will deteriorate.

In this embodiment, focusing on the fact that the first winding (3) has elasticity, the forming pressure is applied intermittently at regular time intervals, and this movement causes the winding gap c! 1 is expanded and contracted.

That is, when the resin (5) fills the mold cavity.

As shown in FIG. 4, the winding gap (to) shrinks and becomes smaller, and even if this state is maintained, the resin (5) is not impregnated to the inside. Therefore, once the molding pressure is reduced, the first winding (3) expands and becomes larger by the first winding gap as shown in Figure 8g3 due to its elasticity, and the impregnability of the resin (5) improves. However, in this state, the molding pressure is low, so 1
Even if the winding gap (■) is large, the resin (5) does not impregnate the inside. Therefore, when molding pressure is applied again, 1 winding (3)
shrinks, but at this time, the resin (5) that has already slightly impregnated the winding gap ■ is in the process of shrinking the zero winding gap ■, and due to the pressure difference, the resin (5) is inside the winding gap ■. pushed into.

In this way, by intermittent molding pressure, the narrow gap ■ can be impregnated with the resin (5) by utilizing the contraction and expansion of the single winding gap ■, resulting in a product with excellent moisture resistance and voltage resistance. It becomes possible to obtain.

In the above embodiment, Ifi and the winding gap ■ were explained, but
For example, the same applies to the cover gap I for voltage resistance and the iron core gap α for water resistance, and the gap 0. Take advantage of the contraction and expansion of the alpha aneurysm.

It becomes possible to impregnate the resin (5) into gaps that were previously impossible to impregnate.

〔Effect of the invention〕

As explained above, in this invention, the molding pressure is intermittent at regular intervals after the mold is filled with resin, so the gap repeatedly expands and contracts, and even the narrow gap is impregnated with resin, resulting in insulation. This has the effect of making it possible to manufacture electric motors with excellent water resistance and the like.

[Brief explanation of the drawing]

1 to 4 are diagrams showing a method of molding a synthetic resin-sealed electric motor according to the present invention, and FIG. 1 is a perspective view of a stator of an outer rotor type DC brushless motor. Figure 2 is a tt-n line sectional view of Figure 1, Figures 3 and 4 are the same <m-m line sectional views, and Figure 5 is a longitudinal cross-section showing a conventional molding method for a synthetic resin-sealed electric motor. It is a diagram. In the figure, (1) is the mold, (2) is the stator core, and (3) is the winding. (5) is a synthetic resin, α3 is a cover gap, and α4 is an iron core gap. cXj is the winding gap. Note that the same reference numerals in the drawings indicate the same or equivalent parts. Figure 1

Claims (1)

[Claims] A stator of an electric motor is placed in a mold, and a synthetic resin in the mold is injected under pressure to seal the stator,
A method for molding a synthetic resin-sealed electric motor, characterized in that the pressurizing force is intermittent at regular time intervals after the mold is filled with the synthetic resin.