JPS6155454B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic molded body with a sheet metal insert, and more particularly to a structural improvement that prevents the sheet metal from being bent by plastic flow.

For example, in an electromagnetic relay in which a coil, a magnetic circuit, a contact spring assembly, etc. are attached to a bottomed box-shaped insulating base, the base 2 that houses the internal structure 1 such as the coil and magnetic circuit as shown in FIG. A mold is formed by inserting a plurality of lead terminals 3 in which fixed contacts and movable contacts are fixed or connected via leaf springs, etc., and a cover 4 is attached.
As shown in FIG. 2, the base body 2 of the electromagnetic relay 5 is constructed by integrally molding a rectangular frame body 6 in plan view and a bottom plate 7, or by molding them separately and then joining them together. Each pair of break fixed contact lead terminals 8, make fixed contact lead terminals 9, and movable contact spring attachment lead terminals 10, whose middle portions are insert-molded in the frame body 6, are attached to the upper surface of the frame body 6. and both ends are led out from a predetermined position on the lower surface.

Figure 3 shows a frame 6 in which the bottom plate 7 is separately molded.
First, as shown in Fig. 3a, two hoop materials such as bronze are pressed and two lead frames 11 to which respective lead terminals 8 to 10 are connected are arranged facing each other in a predetermined manner. do. Then the third
As shown in Figure b, each of the opposing lead terminals 8 to 10
The frame body 6 is formed by molding so that the middle part of the frame body 6 is inserted. Thereafter, the connecting portions of the lead terminals 8 to 10 are cut, contact welding and bending are performed, and the bottom plate 7 (FIG. 2) is bonded to complete the substrate 2 shown in FIG. 2. Note that the bonding of the bottom plate 7 is carried out after the separately assembled internal structure 1 (FIG. 1) is inserted into the frame 6.

However, in order to downsize the electromagnetic relay and minimize the required installation space, it is desirable that the wall thickness of the frame 6 be as thin as possible. At the same time, the arrangement of each lead terminal 8 to 10 led out from the frame 6 is restricted by the configuration of the internal structure 1 and the already standardized relay mounting hole spacing, and the arrangement is centered in the thickness direction of the frame 6. It often happens that it is not located in the Therefore, when molding the frame 6, the fourth
The lead terminals 8 to 10, which must be straight as shown in FIG. As a result, the center portions of the lead terminals 8 to 10 are exposed to the inner surface of the frame 6 and come into contact with the coil inserted into the frame 6, resulting in inconveniences. Therefore,
Place the mold body (frame body 6) by holding the center part of the insert parts (lead terminals 8 to 10) with a pin.
However, such conventional methods have problems such as making holes in the mold body held down by pins, exposing the insert parts and lowering the quality of the product, and requiring work to fill the holes. In addition to having drawbacks, in the case of small molded bodies, it may not be possible to attach a pin for holding the insert part to the molding die.

An object of the present invention is to eliminate the above-mentioned disadvantages, and the object is to form a protrusion projecting toward the thick plastic side on an insert part made of a thin metal plate, so that the protrusion prevents the flow of plastic flowing into the thick plastic side. This is achieved by providing a thin metal plate insert mold body characterized by having an opening that leads a portion to the thin plastic side.

Hereinafter, the present invention will be explained using drawings related to embodiments of the present invention.

FIG. 5 is a plan view a and a bottom view b of a lead frame for an electromagnetic relay according to an embodiment of the present invention, and FIG. 6 is an insert molding of the lead frame shown in FIG. FIG. 7 is a plan view a and a bottom view b of a lead frame for an electromagnetic relay according to another embodiment of the present invention, and FIG. 8 is a side sectional view of the lead frame shown in FIG. FIG. 2 is a side sectional view of a frame body that is insert-molded into a frame for forming a base body.

In FIG. 5 showing a lead frame similar to the lead frame 11 shown in FIG. 3, a lead frame 2 formed by pressing a hoop material such as bronze is shown.
1 is constructed by connecting a fixed contact lead terminal 22 for break, a fixed contact lead terminal 23 for make, and a lead terminal 24 for attaching a movable contact spring. However, square protrusions 25 to 27 that protrude in a predetermined direction are respectively provided in the central wide portion of each lead terminal 22 to 24, and while three sides of the protrusions 25 to 27 are connected to each lead terminal material, Arrow A where plastic flows during insert molding
One side facing the direction forms openings 28-30.

Therefore, as shown in FIG. 6, a pair of lead frames 21 are arranged and fixed facing each other in a mold (not shown), and a plastic frame 31 is molded into which the wide central part of each lead terminal 22 to 24 is embedded. Once formed, the plastic flows through the projection openings 28-3.
After being divided into left and right sides as shown in the figure by 0, they merge at the rear (on the back side of the figure) to fill the mold cavity. At this time, the amount of plastic flowing into the thick side 31' of the frame 31' and the thin side 31'' of the frame 31, respectively, due to the protrusions 25 to 27 and their openings 28 to 30, which project toward the thick side 31' of the frame 31. is significantly similar to that of the conventional lead frame (11 in FIG. 3), and while the pressure of the plastic that has passed through the openings 28 to 30 is increased in the thin walled portion 31'', the pressure of the plastic that has flowed into the thick walled side 31' is passes through the protrusions 25 to 27 and its pressure is reduced. Therefore, each lead terminal 22~
24 will maintain its straight shape.

Lead frame 11 shown in FIGS. 3 and 5
In FIG. 7 showing a lead frame similar to 21 and 21, a lead frame 41 formed by pressing a hoop material such as bronze has a break fixed contact lead terminal 42 and a make fixed contact lead terminal 4.
3 and a lead terminal 44 for attaching a movable contact spring are connected. A U-shaped protrusion 46 is formed at the wide center portion of the lead terminal 43, and two-shaped protrusions 45 and 47 are formed at the wide center portions of the lead terminals 42 and 44. U-shaped or square-shaped openings 48 to 50 are formed below each of the protrusions 45 to 47 shown in FIG. 7b. In addition,
Each of the protrusions 45 to 47 rises in the same direction,
Moreover, it has an inclination of about 45° toward the direction of arrow B in which the plastic flows.

Therefore, as shown in FIG. 8, a pair of lead frames 41 are arranged and fixed opposite each other in a mold (not shown), and a plastic frame 51 is molded into which the wide central portion of each lead terminal 42 to 44 is embedded. When formed, a portion of the plastic that has flowed into the thick side 51' of the frame is guided against each protrusion 45-47, passes through the openings 48-50, and flows into the thin side 51'' of the frame.
The inside of the mold cavity is filled with plastic. At this time, the pressing force of the plastic flow that hits the protrusions 45 to 47 that protrude toward the thick wall side 51' of the frame body is caused by the plastic flow due to the gap difference between the thick wall part 51' and the thin wall part 51'' of the frame body. Eliminates pressure imbalance and connects each lead terminal 45
~47 straightness will be maintained.

As explained above, according to the present invention, insert molding can be performed without deforming a thin plate-like insert component with weak mechanical strength.
The practical effect of not only reducing the defective rate of the conventional molded body but also making the molded body thinner and smaller in size is remarkable.

[Brief explanation of the drawing]

Fig. 1 is a side sectional view showing the main structure of an electromagnetic relay, Fig. 2 is a perspective view of the relay base into which various plate-shaped lead terminals are inserted, and Fig. 3 shows the main steps of making the base. The perspective view shown in FIG. 4 is a side sectional view of the base body, and shows a case a in which a lead terminal (lead frame) is inserted normally and a case b in which a lead terminal (lead frame) is bent and inserted. FIG. 5 is a plan view a and a bottom view b of a lead frame for an electromagnetic relay according to an embodiment of the present invention, and FIG. 6 is an insert molding of the lead frame shown in FIG. 7 is a plan view a and a bottom view b thereof of a lead frame for an electromagnetic relay according to another embodiment of the present invention, and FIG. 8 is a side sectional view of the lead frame shown in FIG. It is a sectional side view which carried out insert molding in the frame for a structure. In addition, in the figure, 2 is the base for electromagnetic relay,
3, 8 to 10, 22 to 24, 42 to 44 are various lead terminals; 6, 31, and 51 are frames for forming a relay base body into which predetermined various lead terminals are inserted and molded; 6', 31', Reference numeral 51' indicates a thick wall portion of each of the frame bodies, 6'', 31'', and 51'' a thin wall portion of each frame body, 11, 21, and 41 a lead frame to which the various lead terminals are connected in a predetermined manner; ~
Reference numerals 27, 45-47 indicate protrusions provided on the lead terminals, and 28-30, 48-50 indicate openings provided in each of the protrusions.

Claims (1)

[Claims] 1. In a plastic molded body in which an insert part made of a thin metal plate is integrated and penetrated in the direction of the plate thickness, the insert part has a protrusion that protrudes toward the thick side of the plastic, and the protrusion is attached to the thick side of the plastic. A thin metal plate insert mold body characterized by having an opening that guides a part of the plastic flow flowing into the plastic to the thin plastic side.