JPS6348043Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to high-frequency switches such as switches and electromagnetic relays that open and close high-frequency signals.

Generally, high-frequency switches that open and close high-frequency signals are required to have isolation between a movable contact piece and a fixed terminal.

In order to satisfy this requirement, in the past, when the movable contact piece is in an open state with respect to the fixed terminal, the distance between the fixed terminal and the movable contact piece is large, and the movable contact piece in this open state is grounded. This reduces the electrostatic coupling and electromagnetic coupling between the movable contact piece and the fixed terminal, and reduces the leakage of high frequency signals between them.

By the way, in general, when grounding a movable contact piece,
The structure is such that the movable contact piece comes into contact with a shield case made by die-casting or hollowing out metal, but in order to improve contact reliability, it is necessary to increase processing accuracy or form small protrusions on the contact surface of the shield case. It is desirable to do so. However, in the case of small-sized products, these processes are often difficult, resulting in high prices.

The purpose of this invention is to provide a high-frequency switch with excellent isolation characteristics that is easy to process and can be manufactured at low cost.

This invention will be described below with reference to an illustrated embodiment.

FIG. 1 is a plan view showing a high-frequency electromagnetic relay, FIG. 2 is a sectional view taken along line A--A in FIG. 1, and FIG. 3 is a schematic exploded perspective view.

A housing is composed of a box-shaped case 1 made of synthetic resin and a card 2. This case 1 includes a recess 1a surrounded by side walls and serving as a room for accommodating a contact circuit section to be described later, and a recess 1f surrounded by side walls for accommodating an electromagnet section to be described later. Furthermore, on the outer circumferential surface,
The ground terminal part 2 should protrude from this case 1.
2 is formed integrally with the case 1. Then, a continuous conductive thin film is formed on the entire inner circumferential surface of the recess 1a and the entire outer circumferential surface of the case 1, including the outer circumferential surface of the ground terminal portion 22, by plating, vapor deposition, painting, etc. (as shown in FIG. 4). 1c), the conductive thin film on the inner surface of this recess 1a and the conductive thin film on the outer circumferential surface of the ground terminal portion 22 are electrically connected. In the recess 1a of the case 1, there is an insulating block 3 made of insulating resin.
d, 4d, 5d are inserted, and the three rod-shaped fixed terminals 3, 4, 5 held by these insulating blocks 3d, 4d, 5d are connected to their contact portions 3a, 4a, 5.
A is fixed inside the case 1, and terminal parts 3b, 4b, and 5b are fixed so as to protrude outside the case 1. The cards 9 and 10 are slidably supported by guide grooves 1d and 1e formed in the case 1, and a movable contact piece 1 is located approximately in the center of the cards 9 and 10.
1 and 12 are fixed respectively. Both ends of the movable contact piece 11 are contactably opposed to the fixed terminals 3 and 4, and both ends of the movable contact piece 12 are contactably opposed to the fixed terminals 4 and 5. Further, the contact portions 11a, 11a, 1 of the movable contact pieces 11, 12
Recessed portion 1a of the case 1 facing 2a and 12a
Four ground contact portions 1b, . As shown in an enlarged view in FIG. 4, this ground contact portion 1b is formed into a protruding shape at a protrusion formed on the side wall of the recess 1a by forming a conductive thin film 1c on the surface of the case 1. be. When a shield card 13 made of a metal plate is attached to cover the recess 1a, a shield housing surrounding the contact circuit is formed by the conductive thin film 1c on the inner surface of the recess 1a and the shield cover 13. Case 1 above
In the recess 1f, the iron core 14, the coil 15, the spool 16, the yoke 17, the movable iron piece 18, and the return spring 1 are installed.
An electromagnet consisting of 9 is fixed. The return spring 19 is clamped at its base by the yoke 17 and the protrusion 1g of the case 1, and has a pressing piece 19a at the free end.
is brought into pressure contact with the movable iron piece 18 hingedly supported by the yoke 17, thereby applying a restoring force to the movable iron piece 18. Both ends of the connecting plate 20 are fitted into the holes 9a and 10a of the cards 9 and 10, so that the cards 9 and 10 are interlocked. A hole 21a is formed in the center of the spring plate 21, and openings 21b, 21b are formed on both sides of the hole 21a.
This spring plate 21 has a hole 21a fitted into a projection 20a projecting downward from the connecting plate 20, and both ends of the spring plate 21 are connected to the projections 20a on both sides of the case 1 so as to bend the entire body.
It is held in the case 1 by pressing it into contact with h and 1h.

Next, the operation of the high frequency electromagnetic relay constructed as described above will be explained.

When the coil 15 is de-energized, the movable iron piece 18 is in the return position as shown in FIG.
is urged upward by the spring force of the spring plate 21 transmitted via the connecting plate 20. Therefore, both ends of the movable contact piece 11 are in contact with the ground contact portions 1b, 1b of the recess 1a, and the fixed terminals 3,
4 rooms are in open state. Further, the movable contact piece 12 has its contact portions 12a, 12a in contact with the contact portions 4a, 5a of the fixed terminals 4, 5.
The space is closed.

When the coil 15 is energized in this state, the movable iron piece 18 rotates clockwise and presses the connecting plate 20 downward against the spring force of the spring plate 21. As the connecting plate 20 descends, the cards 9 and 10 also descend, and the contact portions 11a and 11a of the movable contact piece 11 are connected to the contact portions 3a and 4a of the fixed terminals 3 and 4, and the contact portions 12a and 12a of the movable contact piece 12 are connected to the contact portions 3a and 4a of the fixed terminals 3 and 4, respectively. 12a contacts the ground contact portions 1b, 1b of the recessed portion 1a, respectively. Therefore, the fixed terminals 3 and 4 are closed, and the fixed terminals 4 and 5 are opened. And coil 15
When the energization is stopped, the movable iron piece 18 is returned to its initial position by the spring force of the return spring 19, and the cards 9 and 10 are returned to their initial positions by the spring force of the spring plate 21.

With the above configuration, when fixed terminals 3 and 4 or between 4 and 5 are in an open state,
The movable contact piece 11 or 12 is the ground contact part 1b
Since the movable contact piece 1 is brought into contact with the ground terminal portion 22 and brought into a conductive potential, that is, a ground state, a high frequency signal is transmitted to the movable contact piece 1.
1 or 12, fixed terminals 3, 4
Or there is no risk of closing between 4 and 5,
High isolation can be obtained. Moreover, the shield housing is not formed by hollowing out or die-casting a metal material such as brass to form the case 1 having the recess 1a, but is made of a conductive thin film provided by plating or the like in the recess 1a of the synthetic resin case 1. Earth contact portion 1b,..., 1b
Since the conductive thin film is attached to the surface of the protrusion formed by the groove provided in the molding die during molding of the synthetic resin case 1, the processing cost and material cost are low, and mass productivity is excellent. Moreover, earth contact part 1
Since the dimensional accuracy of b, .

As is clear from the above description, according to this invention, the shield housing that surrounds the contact circuit section consisting of the fixed terminal and the movable contact piece is composed of a conductive thin film formed on the inner surface of the recess of the synthetic resin case. In addition, the ground contact portion is constructed of a conductive thin film on the surface of the protrusion on the inner surface of the recessed portion of the case, and the conductive thin film on the inner surface of the recessed portion is electrically connected to the earth terminal portion protruding to the outside of the case. Since the movable contact piece that is separated from the terminal is brought into contact with the ground contact portion and the movable contact piece is grounded, the distance between the movable contact piece and the fixed terminal can be reduced, and the switch can be made smaller. In addition, it has the effect of improving the dimensional accuracy of the ground contact portion and improving the reliability of contact with the movable contact piece.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway plan view showing a high-frequency electromagnetic relay that is an embodiment of this invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 shows the main parts of this invention. The exploded perspective view and FIG. 4 are cross-sectional views showing the vicinity of the ground contact portion enlarged. 1...Case, 1b...Earth contact part, 1c...
...Conductive thin film, 2...Cover, 3, 4, 5...Fixed terminal, 11, 12...Movable contact piece, 11a, 1
2a...Contact part, 13...Shield cover.

Claims (1)

[Scope of utility model registration request] A synthetic resin base surrounded by side walls and having a recess that serves as a room for storing a contact circuit, a protrusion formed on the inner side wall of the recess, and the recess described above including this protrusion. a conductive thin film formed on the inner surface of the conductive thin film; a ground terminal portion provided on the base so as to be electrically conductive with the conductive thin film and protrude from the base; A pair of fixed terminals fixed in the recess are moved between the pair of fixed terminals and the protrusion, and one moving end electrically contacts the pair of fixed terminals to connect them. and a movable contact piece disposed within the recess so as to short-circuit between the two and electrically contact the conductive thin film on the protrusion at the other moving end.