JPS628935B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to injection molding technology and its apparatus, and more particularly to a mold apparatus used for encapsulating electrical elements.

Insulation of one or more electrical circuit elements having conductors or terminals connected thereto by holding the electrical element in a pot-like container and injecting a fluid insulating material around the electrical element. Molding materials is a common practice. However, conventional methods were slow to operate and did not provide a strong bond between the electrical element and the insulation material. Injection molding using thermoplastics has been an excellent method due to its good sealing properties, short curing time, and high injection molding capacity. However, injecting the thermoplastic around the electrical elements within the mold at high pressures has compromised the alignment between the electrical elements and with respect to the mold walls. This was to affect the heat transfer properties of the electrical elements and thus reduce their efficiency and expected life.

Early attempts to coat electrical components are disclosed in Fischer, US Pat. No. 2,713,700 and Forest et al., US Pat. No. 2,856,639. The Fischer patent presents a technique for enclosing the element body in a protective plastic medium that requires neither high pressures to compromise alignment nor support between opposing mold sections. The Forest et al. patent discloses a method of mounting an electrical coil on a mandrel in a mold and then covering the electrical coil by means of injecting an insulating material into the mold. Further attempts at coating parts are disclosed in McGraw, US Pat. No. 2,747,230. That is, the part is placed between two sections of prefabricated plastic foam, which is then placed into a mold and held in place by projections in the foam. The foam surrounds and protects the component from the cladding and is integral with the cladding. However, the parts are not tightly supported by the cladding.

Techniques for insulating and encapsulating electrical components are disclosed in Alden, US Pat. No. 3,044,127. The method according to this patent comprises the steps of: installing a separate support body in a mold; placing the electrical element on the support to ensure that the electrical element is positioned within the mold; and closing the mold. injecting an insulating material into the mold to at least partially surround the electrical element; and separating the encapsulated electrical element and the support from the mold. It consists of The support body is molded onto the electrical element prior to the second coating.

That is, a first coating is applied to the electrical element separately and prior to placing it in the mold for the second coating. However, the invention described in Alden's U.S. Pat. No. 3,044,127 cannot be applied to all electrical circuits, and there are also problems with the relative positional relationship between electrical elements, surrounding thermoplastics, etc. It does not solve the problems of interconnecting electrical circuits and supporting electrical circuits within the support.

Accordingly, it is an object of the present invention to provide a method for encapsulating electrical circuits containing a number of separate, but interconnected, electrical elements.

Another object of the invention is to provide a support for an electrical element that is encapsulated with the electrical element.

Yet another object of the present invention is to provide a support for electrical elements that maintains alignment between the electrical elements therein during encapsulation while allowing for small deviations in their placement. The goal is to provide the following.

Yet another object of the invention is that the electrical circuit can be easily mounted on a support prior to encapsulation, the support being deformed to align the electrical elements located therein. An object of the present invention is to provide a method for encapsulating an electric circuit in such a way that relationships are maintained.

The present invention relates to the encapsulation of multi-component electrical circuits. A pre-connected electrical circuit is placed on the support. The support has an open end for receiving electrical circuitry and a closed end having a plurality of small orifices. Electrical element leads interconnect through these orifices. The support may also include walls having a suitable structure consisting of curved and flat wall sections for retaining the electrical circuit therebetween, as well as bosses combined with lands, grooves and special orifices. I'm here. The walls of the support are also slightly flexible and flexible to facilitate the insertion of electrical elements. The support itself is adapted to be inserted into the mold, thereby moving the side walls of the support towards each other to align and hold the electrical elements firmly during injection injection of the thermoplastic. . The outside of the side wall of the support is provided with a projection adapted to mate with a detent on the inner wall of the mold, thereby positioning the support within the mold and biasing the side wall appropriately. place. The electrical element leads that extend through the orifice in the support may also extend through the orifice in the mold. The mold has holes to allow trapped air to escape and facilitate injection of the thermoplastic into the mold.

Hereinafter, the present invention will be explained in detail using the drawings. Referring to FIG. 1, a preformed support 20 having the shape of a hollow sword sheath is illustrated. This support 20 is used to cover or encapsulate electrical circuits and the like. The support 20 is constructed from a wall structure. In this embodiment, this wall structure is the end wall 2 of the support 20.
6 includes a first side wall 22 and a second side wall connected on both sides thereof to define a first side wall 22 and a second side wall. Support body 20
also has an open end 28 and a generally closed end 30. However, the closed end 30 includes a plurality of orifices 32, 34 that perform various functions as described below. side wall 22,
A number of external protrusions 36 are provided on the outer surface of 24 . In the embodiment shown in FIGS. 1, 2, and 3, the external protrusion 36 has a hemispherical shape, but it can also have a polyhedral shape.
They also include side walls 22, to form a detent.
It can extend from the outside of 24 toward the inside. The side walls 22, 24 also have a plurality of protrusions 38 thereon. As shown in FIGS. 2 and 3, these protrusions 38 are rectangular in shape and are positioned near and reinforcing the closed end 30 of the support 20. In this embodiment, the support 20 also includes a cylindrical member through which an orifice 34 extends.

Inside the walls 22, 24 and 26, as shown in FIGS. A structure consisting of lands, grooves, and bosses arranged so as to be provided is provided. More specifically, as shown in the end view of FIG.
A first structure consisting of a shallow boss 50 is connected to the side wall 22,
It extends a short length from the inside of 24. The bosses 50 are provided in the support body 20 to face each other and to be spaced apart from each other by a predetermined distance. The end view of FIG. 1 also shows a deep boss 52 structure extending a greater distance from the inside of the side walls 22, 24 than the first boss 50 structure. The second structures including the bosses 52 are provided in the support body 20 so as to be opposed to each other and spaced apart by a predetermined distance. A third structure consisting of a deep boss 54 is provided inside the side walls 22, 24 with a protrusion 56 at its tip.

As shown in FIGS. 1, 4, and 6, in this embodiment, a number of lands 60 are centrally located. As shown in FIGS. 1 and 4, a cylindrical cavity 62
has a number of longitudinally spaced protrusions 64 extending in the same direction as the cavity 62. In this embodiment, cavity 62 has one of the orifices 34 at one end thereof.

As previously mentioned, support 20 is used to insulatively cover, or encapsulate, electrical elements disposed within an electrical circuit. An electrical circuit having a special configuration for engaging a preformed support 20 adapted to receive the electrical circuit is illustrated in FIG. The illustrated electrical circuit 70 has a number of cylindrical elements 72 insertable into the support 20. Electrical circuit 70 may also include other elements such as a jack 74 extending therefrom. Element 72 may have other shapes within support 20 and may include other elements than a jack provided on its exterior.
All of these elements are interconnected by a structure of conductive wires 76, which is within the scope of the present invention. The electrical circuit 70, shown in FIGS. 7 and 10 as extending outside the support 20 and through the orifice 34, includes a run of insulated conductors or wires 78.

The method of encapsulation using a preformed support can optionally include the closed end 30 of the support 20.
The process includes inserting a particular electrical circuit 70 into the support 20 while passing an insulated conductor or wire 78 through an orifice 34 provided in the support 20 . Element 72, which in this example has a cylindrical form, is fitted between shallow bosses 50 that cross one diameter of the support and is mounted between end wall 26 and deep bosses 52. Or the seventh
As shown in the figure, it is installed between a deep boss 52, a deep boss 56 having a protrusion 56, and a pair of shallow bosses 50. In this example,
Spaced projections 64 move element 72 into cavity 6.
Only one element 72 is mounted within the cavity 62, arranged around it to hold it firmly within the cavity 62.

The preformed support 20 with the electrical circuit 70 mounted thereon is itself inserted into an outer mold 80 as shown in FIGS. 7, 8, and 9. It is done like this.
The outer mold 80 includes two or more mold sections 8 that are integrated to surround the preformed support 20 and its associated electrical circuitry 70.
2.84. These can then be separated after completing the process to produce the final product as shown in FIG.
The inner walls of mold sections 82, 84 also include a number of detents 86. This detent 86
Because the side walls 22, 24 of the support 20 are flexible and flex inwardly as the support 20 is inserted into the outer mold 80, the detents 86 are adjacent to the projections 36 of the support 20. Alignment with the outer protrusion 36 serves to properly position the support 20 relative to the outer mold 80 when inserted. One part, the outer protrusion 36 is the outer mold 8
When properly seated within the detents 86 in the 0 walls, the side walls 22, 24 of the support hold each component 72 and bring itself adjacent to its surrounding walls, allowing continuous high temperature During the injection process of thermoplastic plastic at high pressure, the side wall is firmly fixed to prevent it from shifting. Engagement of outer mold parts 82, 84 and side walls 2 of support 20
The forces generated within 2, 24 are shown as arrows "A" in FIG. This is the support 20
This causes the innermost deflection of the side walls 22, 24, indicated by dashed line "B", which occurs when the outer mold 80 is inserted into the outer mold 80.

When the coating, ie, the encapsulating material, is pressed into the cavity of the outer mold 80, the coating not only fills the periphery of the support 20, but also fills the support 20.
It also goes inside 0. They are then integrally combined because they are both made of similar or identical materials. Jack 7 external to support 20
Elements such as 4 are plugged or sealed against injection of the dressing. They are then supported at the top of the mold 80 by retaining means associated with the outer mode 80 and surrounded by a dressing in the same manner as the support 20 and its elements 72.

The previously described orifice 32 in the closed end 30 of the support 20 provides the necessary ventilation for complete filling of the space within the support 20 and other orifices 34. The lands, bosses 50, 52, and 54 on the side walls 22, 24 of the support also help direct the flow of coating material within the support 20, and some of the lands 60 are located on the side walls 22, 24 of the support 20.
Increase the intensity of 2,24. After the coating material filled around the middle and periphery of support 20 within outer mold 80 has cured, the mold portion is removed to expose encapsulated electrical circuitry 90 as shown in FIG.

In summary, the present invention discloses a method and apparatus for molding entire electrical circuits, including active and passive components, in which a support is specifically adapted to each particular electrical circuit configuration. ,
A large number of lands are provided in combination with a cylindrical cavity and flexible wall sections that hold the entire electrical circuit firmly during the encapsulation process at high pressures.
It has a groove and a boss. The flexibility of the side walls of the support allows a pre-assembled electrical circuit consisting of electrical elements to be inserted into the mold, and the projections and detents made to match them are aligned prior to alignment. to form a clearance between the support and the mold. The lands and bosses then serve to firmly fix the element between them after deflection of the sidewall and to regulate the flow of the covering material around it.

[Brief explanation of the drawing]

FIG. 1 is an end view of an electrical circuit supported by a support according to the present invention. Figure 2 shows
FIG. 2 is a front view of the support of FIG. 1; Figure 3 shows the first
FIG. 3 is a side view of the support shown in the figure; FIG. 4 is a sectional view taken along the - line in FIG. 1. FIG. 5 is a sectional view taken along the - line in FIG. 2. FIG. 6 is a cross-sectional view of a support having an electrical circuit therein. Figure 7 shows - of Figure 6.
FIG. 3 is a cross-sectional view taken along the line. FIG. 8 is a cross-sectional view of the support placed within the support mold.
FIG. 9 is a partial cross-sectional view of an electrical element provided within a support which is itself disposed within a support mold. FIG. 10 is a side view of the encapsulated electrical circuit and support removed from the mold. 20... Support body, 22, 24... Side wall, 28...
...open end, 30...closed end, 32, 34...orifice, 36...external projection, 50, 52, 54...
...Boss, 56...Protrusion, 60...Land, 62...
...Cavity, 70...Electric circuit, 72...Element, 74...Jack.

Claims (1)

[Claims] 1. A method for encapsulating electrical elements, comprising:
inserting the electrical element between and within the support; housing the support in a mold; and engaging the side walls of the support with the mold; and deflecting the sidewalls of the support with a force exerted by the closure of the mold on the support, further causing the inner sidewalls of the support to engage the electrical element in a gripping manner. and injecting the coating material into the mold while holding the electrical element as described above against movement due to the flow of the coating material. 2. A support device for holding an electrical element during encapsulation in a mold, the support having opposing side walls, at least one of which is flexible relative to the other; means provided in the sidewall for engaging opposite sides of the electrical element and positioning the electrical element relative to the opposing sidewalls, the means being provided on the sidewalls for engaging opposite sides of the electrical element and positioning the electrical element relative to the opposing sidewalls; means for gripping the electrical element; and means for interengaging the support and the mold to deflect sidewalls of the support, thereby applying the gripping force to the electrical element. A support device consisting of; 3. The support device of claim 2, wherein the support is configured to interengage the support and the mold to bias side walls of the support, thereby causing the electrical element to have the grip. A support further comprising: means for applying force; 4. The support device according to claim 2, wherein the support body includes the mutual engagement means. 5. The support device according to claim 4, wherein the mutual engagement means comprises a protrusion projecting to the outside of the support beyond the outer surface of the flexible side wall of the support. Support equipment.