JPS5848817Y2 - Ladder type filter - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to the structure of a ladder type filter in which piezoelectric ceramic resonators and electrode plates are alternately inserted and arranged in a case.

First, let's talk about the conventional ladder type filter of this type.
This will be explained with figures.

In Fig. 1, reference numeral 1 denotes a box-shaped inner case, into which piezoelectric ceramic resonators 2 and electrode plates 3 are inserted alternately, and a U-shaped sheet plate 4 is inserted. In order to adjust the pressure that clamps the resonator 2 and to hold each component, a spacer 5 and an elastic body 6 are inserted, and the inner case 1 is inserted into the outer case 7.

Note that the terminal portion of the electrode plate 3 protrudes through a hole formed in the bottom surface of the inner case 1.

Reference numeral 8 indicates a silicon rubber coated on the edge of the hole on the bottom surface of the inner case 1 through which the terminal portion of the electrode plate 3 passes and the boundary between the inner case 1 and the outer case 7; 9 indicates an opening in the outer case 7; This is an epoxy resin filled in the epoxy resin.

However, in the conventional ladder type filter described above, each component must be inserted into the inner case 1 in a direction perpendicular to the arrangement direction of the components, and in particular, internal pressure caused by variations in the thickness of the piezoelectric ceramic resonator 2 must be avoided. When making adjustments, it is necessary to sequentially insert and remove several types of spacers 5 with different thicknesses to obtain the appropriate pressure, and the workability, especially the workability of adjusting the internal pressure by inserting and removing the spacers, is poor, and it is difficult to adjust the internal pressure by inserting and removing the spacers. It was impossible to assemble.

The present invention eliminates the above-mentioned drawbacks of the conventional art, and one embodiment of the present invention will be described below with reference to FIGS. 2 and 3.

In FIGS. 2 and 3, 11 is a case made of resin or the like, and this case 11 has a columnar hole 12 into which a component is inserted.

13 and 13' are slits extending in the axial direction of the hole 12 in the side wall of the case 11 and passing through the columnar hole 12, respectively.

14 is a stopper plate formed between the above-mentioned sleeves 13 and 13', and this stopper plate 14 is formed between the above-mentioned columnar holes 1.
This is a part of the side wall of No.2.

Note that the upper surface and the peripheral edge of one side of the case 11 protrude.

Inside the columnar hole 12 of the case 11, as shown in FIG.
are inserted sequentially.

Note that the terminal portion of the electrode plate 16 passes through the slit 13 or 13' and projects to the outside.

Reference numeral 18 denotes a lid plate attached to the upper surface of the case 11, and the opening surface of the columnar shape (L12) is closed by this lid plate 18.

One is a conductor connecting between the electrode plates 17.

In Fig. 3, 20 is a sealing plate, 21 is the case 1
This is an epoxy resin filled on the side surface of the ribs 1-1-13 and 13'.

The ladder-type filter of the present invention has the above-mentioned structure, and is assembled by sequentially inserting the parts into the columnar holes of the case in the direction of their arrangement, which makes it possible to mechanize the assembly work and is suitable for mass production. It is something.

In addition, according to the present invention, there is no need for an outer case like in the conventional example, and the structure is simple and the number of parts is reduced.
Moreover, it has the advantage that the internal pressure can be easily adjusted.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a conventional ladder type filter, FIG. 2 is an exploded perspective view of a ladder type filter according to an embodiment of the present invention, and FIG. 3 is a sectional view thereof. 11...Case, 12...Column hole, 1
3.13'...Slit, 14...Stopper plate, 15...Elastic body, 16...
・Electrode plate, 17...Piezoelectric ceramic resonator, 1
8... Lid plate, 19... Conductor, 20...
...Filling plate, 21...Epoxy resin.

Claims (1)

[Scope of utility model registration request] Two snots extending in the direction of the central axis of the columnar hole and communicating with the columnar hole are formed on the side wall of a case having a columnar hole, and an elastic body, a piezoelectric ceramic resonator, and an electrode plate are sequentially inserted into the columnar hole. A ladder-type filter in which the electrode plates are laminated, both terminals of the electrode plates are led out through the slits, and the openings of the columnar holes are closed with a cover plate.