JPH0541222U - Ladder type filter - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] Ladder type filter with excellent productivity, which can stably hold the piezoelectric resonator with the terminal plate and does not cause short circuit between the spring terminal plate and the lead part of the terminal plate. I will provide a. Ladder in which terminal plates 5, 7, 9 and piezoelectric resonators 6, 8 are sequentially stacked in a case 2, a spring terminal plate 10 is placed, and a case opening 2a is sealed by a sealing portion 4. This is a ladder filter in which a spring terminal plate 10 is provided with an extending portion 10a directed toward an opening, and the extending portion 10a is fixed by the sealing portion 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a ladder type filter, specifically, a structure of a spring terminal housed in a case.

[0002]

[Prior art]

 Conventionally, there has been a ladder type filter shown in FIG. 5 as a ladder type filter. The structure will be described using a basic two-element ladder filter.

The ladder filter 50 has a case 51 and a filter member group 52 housed in the case 51. The filter member group 52 housed in the case 51 includes a first terminal plate 53, a series resonator 54, a second terminal plate 55, a parallel resonator 56, a third terminal plate 57, and a spring terminal plate 58 from the bottom of the figure. It is stacked. Here, each of the first terminal plate 53, the second terminal plate 55, and the third terminal plate 57 has a projecting portion 59 at the central portion of the main surface that contacts the resonator on both main surfaces thereof. The first terminal plate 53, the second terminal plate 55, and the third terminal plate 57 respectively extend lead terminals 53b, 55b, and 57b that extend perpendicularly to the terminal surface and are exposed from the opening 51a of the case 51. Have The lead terminals 53b, 55b, 57b are formed on the same plane so that they can be surface-mounted on the printed wiring board.

The spring terminal plate 58 has a rectangular shape in which a metal flat plate having a spring property is curved, and the series resonator 54 and the parallel resonator 56 are connected to the first terminal plate 53, the second terminal plate 55, The protrusion 59 of the third terminal plate 57 is arranged to achieve mechanical clamping and electrical connection.

The opening 51 a of the case 51 is sealed by a sealing portion composed of a partition plate 60 made of paper or resin and a filling seal material 61 on the inner side. On the outer peripheral portion of the partition plate 60, slit-like cutout portions 62 through which the lead portions 53a, 55a, 57a pass are formed, respectively. Further, a liquid resin filling sealing material 61 is injected into the space A between the partition plate 60 and the opening 51a of the case 51 and cured.

As a result, the airtightness inside the case 51 is improved by the partition plate 60 and the filling sealing material 61, and a ladder type filter having stable filter characteristics is achieved.

The ladder type filter having such a structure is assembled by the manufacturing method shown in FIG.

The first to third terminal plates 53, 55, 57 are integrated with the frames 53c, 55c, 57c via the lead portions 53a, 55a, 57a in consideration of productivity. For example, the lead portions 53a, 55a, 57a of the terminal plates 53, 55, 57 extend so as to be perpendicular to the terminal surface, and are further bent at the opening 51a of the case 51 to form frames 53c, 55c, 57c. Connected with.

The first terminal plate 53 integrated with such a frame 53c is housed in the case 51, and the second terminal plate 55 integrated with the series resonator 54 and the frame 55c is further provided on the first terminal plate 53. , The parallel resonator 56, the third terminal plate 57 integrated with the frame 57c, and the spring terminal plate 58 are sequentially placed. Next, a partition plate 60 for closing the opening 51a of the case 51 is attached, and although not shown in FIG. 6, after the filling sealing material 61 is poured into the space A and cured, the lead portions 53a and 55a are , 57a were extended from the case opening 51a by a predetermined length and were cut by XX line. As a result, the lead terminals 53b, 55b, and 57b extend from the case opening 51a by a predetermined length.

[0010]

[Problems to be solved by the device]

 However, in the above-mentioned structure, the spring terminal plate 58 has a rectangular shape and is in the shape of a bowl with a predetermined thickness in the center, and is placed on the third terminal plate 57 with a gap of 0.1 to 0.2 mm on the inner wall of the case. It had been. Since the lower surface side of the spring terminal plate 58 is convex and easily slips on the terminal plate 57, it is difficult to fix the position of the spring terminal 58. Further, as a result of displacement, one end of the spring terminal plate 58 is partitioned. When the board 60 is mounted, it has a problem that the board 60 is destroyed when the board 60 is press-fitted.

Furthermore, depending on the position of the spring terminal plate 58, if the lead terminal 53a, 55a, 57a extending from the first to third terminal plates 53, 55, 57a is sealed in a short-circuited state, the filter characteristics may be reduced. There was a possibility of causing a fatal problem that it could not be obtained.

The present invention has been devised to solve the above-mentioned problems, and provides a ladder-type filter with improved productivity and stable filter characteristics.

[0013]

[Specific means for solving the problem]

 According to the present invention, a terminal plate and a piezoelectric resonator are laminated on each other in a case having an opening on one side, and the case opening is sealed by a partition plate and a seal material via a spring terminal plate. In the ladder type filter, the spring terminal has an extending portion extending to the outside of the partition plate and is fixed by the sealing material.

[0014]

[Action]

 According to the method of the present invention, a part of the spring terminal plate housed inside the case is fixed by the partition plate and the sealing material. For this reason, the spring terminal plate is fixed in place in the case, so there are no short-circuits with the leads extending from the terminal plate, and there are no assembly problems due to misalignment, and the filter characteristics are long-term. It becomes a stable ladder type filter.

Further, the extended part of the spring terminal plate is integrally formed with the lead frame similarly to the lead terminal of the terminal plate, so that the productivity at the time of stacking and assembling is improved.

[0016]

【Example】

 Hereinafter, a method of manufacturing a ladder type filter of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external perspective view of a ladder type filter according to the present invention, and FIG. 2 is a sectional structural view. Note that the simplest two-element type filter will be used as the ladder type filter for explanation.

In the figure, a ladder type filter 1 is composed of a case 2, a filter member 3 in which a piezoelectric resonator and a terminal plate are stacked, and a sealing member 4 for sealing the case 2.

The case 2 is made of a heat-resistant resin such as PPS and is a hollow and substantially rectangular parallelepiped member. An opening 2a is formed at one end of the case 2.

The filter member group 3 housed in the case 2 includes a first terminal plate 5, a series resonator 6, a second terminal plate 7, a parallel resonator 8, a third terminal plate 9 and a spring from the bottom of FIG. The terminal boards 10 are stacked. Here, each of the terminal plates 5, 7, and 9 has a substantially rectangular shape, and projections 11 ... Are formed on the surfaces in contact with the series resonator 6 and the parallel resonator 8. The protrusions 11 ... Are formed by pressing, for example.

The series resonator 6 and the parallel resonator 8 are made of a piezoelectric ceramic member having electrodes (not shown) formed on both principal surfaces thereof, and have a substantially square shape. The thickness of the series resonator 6 is set larger than that of the parallel resonator 8.

Each terminal plate 5, 7, 9 has lead terminals 5 b, 7 b, 9 b extending in the direction of the opening 2 a of the case 2 and further bent at the end face of the opening 2 a.

The spring terminal plate 10 is made of elastic metal such as phosphor bronze and has a thickness of 0.1 mm, and a predetermined force is applied to the piezoelectric resonators 6 and 8 and the terminal plates 5, 7, and 9. As described above, it has a recess having a central height of about 0.3 mm. As a result, a predetermined elastic force is applied to the piezoelectric resonators 6 and 8 and the terminal plates 5, 7 and 9, and the piezoelectric resonators 6 and 8 are securely sandwiched between the terminal plates 5, 7 and 9 and electrically connected. Will be achieved. Similarly to the terminal plates 5, 7, and 9, the spring terminal plate 10 extends toward the opening 2a through the lead portion 10a, and is further integrated with the lead frame 10c. The opening 2a of the case 2 in which the filter member group 3 is housed is completely sealed by the sealing portion 4 including the partition plate 12 and the sealing material 13. The partition plate 12 is made of paper or a resin member, and at positions corresponding to the respective lead portions 5a, 7a, 9a, the lead terminals 5b, 7b, 9b and the lead portion 10a can be penetrated as shown in FIG. Although not shown, the notches 14 ...

The sealing material 13 is, for example, an epoxy resin, and a liquid resin is injected into a space A surrounded by the opening 2 a of the case 2, the opening inner wall and the partition plate 12, and then cured by heating or the like. As a result, the opening 2a is hermetically sealed.

Next, the assembly process of the present invention will be described with reference to FIG.

First, the first terminal plate 5 integrated with the lead frame 5 c is arranged in the housing portion of the case 2 through the opening 2 a of the case 2. Then, the series resonator 6, the second terminal plate 7 integrated with the lead frame 7c, the parallel resonator 8, and the third terminal plate 9 integrated with the lead frame 9c are sequentially laminated on the first terminal plate 5. Finally, the spring terminal plate 10 integrated with the lead frame 10c is arranged.

Next, in order to close the opening 2a of the case 2, the partition plate 12 is press-fitted and mounted. From the notch 14 around the partition plate 12, the first to third terminal plates 5, 7, 9 and the lead terminals 5b, 7b, 9b extending from the spring terminal 10 and the lead portion 10a extend.

In this state, the filling seal member 13 is injected into the space A surrounded by the inner wall of the opening 2 a of the case 2 and the partition plate 12, and is further cured by heating. As a result, the lead terminals 5b, 7b, 9b and the lead portion 10a existing in the space A are embedded and fixed.

Finally, X-X of the lead portions 5a, 7a, 9a between the lead terminals 5b, 7b, 9b extending from the first to third terminal plates 5, 7, 9 and the lead frames 5c, 7c, 9c. The lead portion 10a extending from the wire and the spring terminal plate 10 is cut in the vicinity of the portion intersecting the outer wall surface of the case 2, and the ladder type filter 1 and the lead frames 5c, 7c, 9c and 10c are separated.

A feature of the present invention is that, as shown in FIG. 4, the lead portion 10 a extending from the spring terminal plate 10 is fixed by the sealing portion 4, that is, the partition plate 12 and the sealing material 13. As a result, the spring terminal plate 10 laminated on the third terminal plate 9 is positioned at a predetermined position, that is, the central concave portion is located at the central portion of the terminal plate 9, and is further securely fixed at that position. Therefore, the lead terminals 5b and 7b of the first and second terminal plates 5 and 7 do not come into contact with each other, and the piezoelectric resonators 6 and 8 and the terminal plates 5, 7 and 9 are stabilized via the third terminal plate 9. The elastic force can be applied. Therefore, the piezoelectric resonators 6 and 8 can be reliably sandwiched between the terminal plates 5, 7, and 9, and more stable electrical connection can be obtained. In addition, it is possible to achieve a ladder type filter that has stable filter characteristics over a long period of time and under severe operating conditions.

Further, the spring terminal plate 10 is integrated with the lead frame 10c, and the piezoelectric resonators 6, 8 and the terminals are provided in the case 2 by the same assembling method as the other terminal plates 5, 7, 9. Since the bodies 5, 7, 9 and the spring terminal 10 are stacked, the stacking can be easily performed without causing the stacking deviation, and the productivity thereof is significantly improved.

In the above-mentioned embodiment, the two-element type ladder type filter has been described, but the same structure can be applied to a four-element, six-element, etc. ladder-type filter. In addition to the mounted ladder type filter, a lead type ladder type filter may be used.

[0032]

【effect】

 According to the present invention, since a part of the spring terminal plate is fixed by the sealing portion, the battery terminal plate can be arranged at a predetermined position, and further, the spring terminal plate causes a short circuit with the terminal plate lead portion. A ladder type filter with stable filter characteristics that does not occur at all. Further, since the terminal board and the terminal board can be laminated in the same step in the case, the productivity in the laminating step is improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a ladder type filter according to the present invention.

FIG. 2 is a sectional view taken along line YY of FIG.

FIG. 3 is an exploded view for explaining an assembly process of the ladder type filter of the present invention.

FIG. 4 is a partially enlarged view showing a relationship between a spring terminal plate and a sealing portion.

FIG. 5 is a cross-sectional view of a conventional ladder type filter.

FIG. 6 is an exploded view for explaining a conventional ladder-type filter assembling process.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Ladder type filter 2 ... Case 3 ... Filter member group 4 ... Sealing part 5, 7, 9 ... Terminal plate 10 ... Spring terminal plate 5a, 7a, 9a 10a ... Lead parts 5c, 7c, 9c, 10c ... Lead frame

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Kazuo Nakamura 1-1 1-1 Yamashita-cho, Kokubun-shi, Kagoshima Prefecture Kyocera Kokubun Factory

Claims (1)

[Scope of utility model registration request] 1. A terminal plate in a case having an opening on one side,
A ladder-type filter comprising a piezoelectric resonator and a piezoelectric resonator laminated on each other, and the case opening sealed by a partition plate and a sealing material via a spring terminal plate, wherein the spring terminal extends to the outside of the partition plate. A ladder-type filter having an extending portion and fixed by the sealing material.