JPH0570027U - Ladder type piezoelectric component - Google Patents

Abstract

(57) [Summary] [Purpose] In a ladder-type ceramic filter, it prevents the occurrence of a short circuit due to routing of the lead part and simplifies the shape of the base plate that closes the opening of the case. In a piezoelectric unit B including a plurality of terminal plates 1, 6, 8 and a plurality of piezoelectric elements 2, 5, 7, 9, a lead portion of an input terminal plate 1 and an output terminal plate 8 arranged at the ends Bend 15 and 18 and align with the lead portion 12 of the central earth terminal plate 6 in a line. The piezoelectric unit B is a case 23.
Store inside. The base plate 24 that closes the opening of the case 23 has a symmetrical shape with respect to its center line CL-CL, and three terminal lead-out holes 26, 27, 26 are provided in a line at the center thereof, and the lead portions 15, 12, 18 are connected to the terminals. Drawout hole 2
Pull out from 6, 27, 26. A node pressing portion 25 is provided on the inner surface of the base plate 24 so that the node pressing portion 25 presses the end surfaces of the piezoelectric elements 2, 5, 7, 9 to hold them stably.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a ladder type piezoelectric component. Specifically, it relates to a piezoelectric component such as a ladder-type ceramic filter having a built-in ladder-type circuit formed of piezoelectric elements.

[0002]

[Background technology and its problems]

 FIG. 5 is a sectional view showing a conventional ladder type ceramic filter C, and FIG. 6 is a perspective view showing a piezoelectric unit D incorporated in the ladder type ceramic filter.

Conventionally, as shown in FIG. 6, the piezoelectric unit is composed of an input terminal plate 51, a serial piezoelectric element 52, a contact portion 54a of a U-shaped conductor plate 53 for internal connection, and a parallel piezoelectric element. 55, a ground terminal plate 56, a parallel piezoelectric element 57, an output terminal plate 58, a series piezoelectric element 59, and a contact portion 54b of the internal connecting conductor plate 53 are arranged in this order.

The output terminal plate 58 has a lead portion 60 extending straight from a position offset to one side in the width direction (direction perpendicular to the arrangement direction). Further, the ground terminal plate 56 is provided with a lead portion 61 at the center in the width direction. The lead portion 61 of the ground terminal plate 56 is bent twice at a substantially right angle, and the lead lead-out portion 61b at the tip is arranged in a line with the lead portion 60 of the output terminal plate 58. Further, the lead portion 62 of the input terminal plate 51 is provided at a position offset to the side opposite to the lead portion 60 of the output terminal plate 58. The lead portion 62 is also bent twice at a substantially right angle, and the lead lead-out portion 62b at the tip portion is arranged in line with the lead portion 60 of the output terminal plate 58 and the lead lead-out portion 61b of the ground terminal plate 56. Therefore, the lead lead-out portion 62b of the input terminal board 51, the lead lead-out portion 61b of the ground terminal board 56, and the lead portion 60 of the output terminal board 58 are arranged in a row in the width direction.

As shown in FIG. 5, the piezoelectric unit D is housed in a case 63, and then an opening of the case 63 is covered with a base plate 64 which is a resin injection molded product, and an epoxy is applied from above the base plate 64. The opening portion of the case 63 is sealed with a sealing resin 65 such as a resin to seal the inside of the case 63. Further, the base plate 64 has three terminal lead-out holes 66, 67, 68 opened in a line, and the lead portion 60 and the lead lead-out portion led out to the outside through the terminal lead-out holes 66, 67, 68. 61b and 62b are bent along the outer surface of the end of the case 63 on the side closer to the output terminal board 58.

Therefore, in the conventional ladder-type ceramic filter C, the terminal lead-out holes 66, 67, 68 are opened in a line at a position deviated from the center of the base plate 64, and at the time of assembly, the terminal lead-out holes 66, 67, 68 are formed. It was necessary to attach the lead-out holes 66, 67, 68 to the opening of the case 63 so that the open side thereof faces the output terminal plate 58 side of the piezoelectric unit D housed in the case 63. As described above, since the base plate 64 is mounted in the case 63 in a certain direction, it is difficult to automate the assembly.

In addition, in the ladder-type ceramic filter C as described above, the lead portion 62 of the input terminal board 51 located at one end in the arrangement direction is connected to the lead portion of the output terminal board 58 located at the other end. Since it extends horizontally to the position of the portion 60, the length L of the horizontally extending portion 62a of the lead portion 62 of the input terminal board 51 is long. Therefore, the lead portion 62 of the input terminal plate 51 is easily bent by the external force during assembly, and the lead portion 62 comes into contact with the internal connection conductor plate 53, the piezoelectric elements 52, 55, 57, and the ground terminal plate 56, and the There was a risk of a short circuit.

In order to prevent such an electrical short, in the conventional ladder type ceramic filter C, as shown in FIG. 7, two leads, long and short, which communicate with the terminal lead-out holes 68 and 67, are formed on the inner surface of the base plate 64. The housing grooves 69, 70 are provided as recesses, and the horizontally extending portion 61a of the lead portion 61 of the ground terminal plate 56 and the horizontally extending portion 62a of the input terminal plate 51 are respectively inserted into the lead housing grooves 70, 69. It escapes and prevents the horizontally extending portion 62a of the input terminal plate 51 and the like from coming into contact with the conductor plate 53 for internal connection and the piezoelectric elements 52, 55, 57 and the like.

However, in the base plate 64 provided with such lead storage grooves 69 and 70, it is not easy to manufacture the base plate 64 by resin molding because the shape of the base plate 64 is complicated. The injection molding die also had a complicated shape.

[0010]

[Problems to be solved by the device]

 The present invention has been made in view of the above-mentioned drawbacks of the conventional example, and an object thereof is to simplify the shape of the base plate for closing the opening of the case to facilitate the manufacture of the base plate. (EN) Provided is a ladder-type piezoelectric component which facilitates automatic assembling of a base plate into a case and can prevent an electrical short circuit due to a lead portion of the terminal plate coming into contact with another terminal plate or a piezoelectric element. It is in.

[0011]

[Means for Solving the Problems]

 The ladder-type piezoelectric component of the present invention accommodates a piezoelectric unit that forms a ladder-type circuit by arranging a plurality of piezoelectric elements and three or more terminal plates in a case, and closes the opening of the case with a base plate. A piezoelectric component obtained by penetrating each of the terminal plates into the base plate and pulling it out of the case, of the three or more terminal plates, at least leads of the terminal plates other than the terminal plates located at substantially the center in the arrangement direction. By bending the parts, the lead parts of all the terminal plates are aligned in a line in the direction orthogonal to the arrangement direction in the approximate center of the base plate, and the three parts are opened in a line in the approximate center of the base plate. It is characterized in that the lead portions of the respective terminal plates are inserted into the above-mentioned terminal lead-out holes, respectively.

Further, a node pressing portion may be provided on the inner surface of the base plate so as to be substantially parallel to the arrangement direction.

[0013]

[Action]

 According to the present invention, the lead portions of each terminal plate are aligned with the center of the base plate and are inserted into the respective terminal lead-out holes opened in a line at the center of the base plate. There is no need to pull the lead part from end to end in the arrangement direction in order to insert the lead part through. Therefore, a portion extending in parallel to the arrangement direction of the lead portions is less likely to bend due to an external force applied during assembly, and the lead portions can be prevented from coming into contact with another terminal plate, a piezoelectric element, or the like to cause a short circuit.

Therefore, it is not necessary to provide a lead storage groove for preventing a short circuit on the inner surface of the base plate as in the conventional case, and the shape of the base plate can be simplified. Therefore, when the base plate is resin-molded, for example, the resin molding of the base plate can be facilitated.

Further, since the terminal lead-out hole is opened at approximately the center of the base plate so that the base plate has a symmetrical shape, it is possible to eliminate the directionality when assembling the base plate into the case, and to automate the assembly work. Can be facilitated.

Further, since the node pressing portion is provided on the inner surface of the base plate so as to project, the node pressing portion is brought into contact with the end surface of each piezoelectric element to stably hold the piezoelectric element so as not to move in the case. Therefore, the characteristics of the piezoelectric element can be improved.

[0017]

【Example】

 FIG. 1 is a sectional view showing a ladder type ceramic filter A according to an embodiment of the present invention, and FIG. 2 is a perspective view showing a piezoelectric unit B incorporated in the ladder type ceramic filter A.

As shown in FIG. 2, the piezoelectric unit B includes an input terminal plate 1, a series piezoelectric element 2, a contact portion 4 a of a U-shaped conductor plate 3 for internal connection, a parallel piezoelectric element 5, and a ground terminal plate. 6, the parallel piezoelectric element 7, the output terminal plate 8, the series piezoelectric element 9, and the contact portion 4b of the internal connecting conductor plate 3 are arranged in this order.

Each of the piezoelectric elements 2, 5, 7, and 9 is a piezoelectric resonator of a spreading vibration mode, and electrode films are formed on both surfaces of these piezoelectric elements 2, 5, 7, and 9.

In the contact portion 10 of the ground terminal plate 6 which is sandwiched between the parallel piezoelectric elements 5 and 7, a protrusion 11 is provided at the center of both surfaces, and the protrusion 11 is formed by both parallel piezoelectric elements. The elements 5 and 7 are in pressure contact with the central portions of the electrode films. The ground terminal plate 6 is located substantially at the center of the piezoelectric unit B in the arrangement direction, and the lead portion 12 extends straight from the center of the electric contact portion 10 in the width direction (direction perpendicular to the arrangement direction). ing.

In the contact portion 13 of the input terminal plate 1 facing the series piezoelectric element 2, a protrusion 14 is provided at the center of the series piezoelectric element 2 side. It is pressed against the central portion of the electrode film of the element 2. Further, the lead portion 15 of the input terminal board 1 is provided on one side in the width direction of the electric contact portion 13, and the base end portion is bent to be parallel to the arrangement direction. After being extended horizontally, it is bent vertically at about 90 degrees at the position of the lead portion 12 of the ground terminal plate 6.

The contact portion 16 of the output terminal plate 8 sandwiched between the parallel piezoelectric element 7 and the series piezoelectric element 9 is also provided with a protrusion 17 at the center of both surfaces. Are pressed against the central portions of the electrode films of the parallel piezoelectric element 7 and the series piezoelectric element 9. Further, the lead portion 18 of the output terminal board 8 is provided on a side portion in the width direction on the side opposite to the lead portion 15 of the input terminal board 1, and the base end portion is bent so that the electric contact portion 16 is connected to the ground terminal board 8. After extending to the position of the lead portion 12 of 6 in parallel with the arrangement direction, it is bent substantially 90 degrees at the position of the lead portion 12 of the ground terminal plate 6. Therefore, the lead lead-out portions 15b and 18b at the respective tips of the lead portions 15 and 18 of the input and output terminal plates 1 and 8 and the lead portion 12 of the ground terminal plate 6 are arranged in a row in the width direction.

In addition, the projections 19 projecting on both surfaces of the contact portion 4 a of the internal connection conductor plate 3 sandwiched between the series piezoelectric element 2 and the parallel piezoelectric element 5 are arranged in parallel with the series piezoelectric element 2. Each electrode film of the piezoelectric element 5 is in pressure contact. Further, the protruding portion 20 protruding from the contact portion 4 b facing the series piezoelectric element 9 toward the series piezoelectric element 9 side is pressed against the central portion of the series piezoelectric element 9. The two electric contact portions 4a and 4b are electrically connected to each other through a connecting portion 4c located on the outer side in the width direction (the other side in FIG. 2), and the internal connecting conductor plate 3 is formed in a substantially U shape. Has been done.

FIG. 4 is an equivalent circuit diagram of the piezoelectric unit B (or the ladder-type ceramic filter A) configured as described above, which shows two series piezoelectric elements 2 and 9 and two parallel piezoelectric elements. A ladder type circuit is constituted by the piezoelectric elements 5 and 7.

Thus, the piezoelectric unit B is housed in the case 24 with both ends sandwiched by the filling member 21a and the leaf spring 22 and the filling member 21b. The piezoelectric unit B is held by the elastic force of the leaf spring 22 without rattling. The filling members 21a and 21b made of a metal plate or the like are adjustment members for filling the space between the case 24 and the piezoelectric unit B.

FIG. 3 shows a base plate 24 for closing the opening of the case 23. The base plate 24 is a resin molded product, and a node pressing portion 25 is projectingly provided over the entire length at the center of the inner surface of the base plate 24. Further, three terminal lead-out holes 26, 27, 26 are formed in the center in the direction parallel to the node pressing portion 25. The central terminal lead-out hole 27 penetrating the node pressing portion 25 is a hole for pulling out the lead portion 12 of the ground terminal plate 6. The two terminal lead-out holes 26, 26 formed at equal intervals on both sides are holes for leading out the lead lead-out portions 15b, 18b of either the input terminal board 1 or the output terminal board 8. Since the terminal lead-out holes 26, 27, 26 are provided in the center of the base plate 24, the lengths L1, L2 on both sides of the terminal lead-out holes 26, 27, 26 of the base plate 24 are substantially equal. Therefore, the base plate 24 has a symmetrical shape with respect to the virtual center line CL-CL passing through the terminal lead-out holes 26, 27, 26.

The base plate 24 holds the node while holding the lead lead-out portions 15 b and 18 b of the input / output terminal plates 1 and 8 and the lead portion 12 of the ground terminal 6 in the terminal lead-out holes 26, 26 and 27. It is inserted into the case 23 with the surface on the side where the portion 25 is formed facing inward. At this time, the top surface of the node pressing portion 25 is brought into contact with the node portion of the end surface of each piezoelectric element 2, 5, 7, 9. Therefore, the piezoelectric elements 2, 5, 7, 9 are stably held in the case 23 without rattling without being disturbed by vibration. The horizontally extending portions 15a and 18a of the lead portions 15 and 18 of the input and output terminal plates 1 and 8 are wired in the space between the base plate 24 and the piezoelectric unit B formed by the node pressing portion 25. Therefore, it is possible to prevent a short circuit between the terminal plates and a short circuit between each terminal plate and the internal connecting conductor plate 3, the piezoelectric elements 2, 5, 7, 9 and the like. Moreover, since the horizontally extending portions 15a and 18a of the lead portions 15 and 18 are not extremely long as in the conventional example, the horizontally extending portions 15a and 18a of the lead portions 15 and 18 are less likely to bend. Further, it is possible to further prevent the lead portions 15 and 18 from being short-circuited.

As a procedure of assembling, the lead portions 15, 12, 18 of the terminal plates 1, 6, 8 are inserted into the terminal lead-out holes 26, 27, 26 of the base plate 24, and the base plate 24 is placed. After the piezoelectric unit B is placed on, the case 23 may be placed on the piezoelectric unit B from above.

After that, a sealing resin 28 such as an epoxy resin is injected outside the base plate 24 and cured to seal the piezoelectric unit B in the case 23. Then, the lead portions 15, 12, 18 protruding outside are bent at a right angle in any direction to be along the outer surface of the case 23 to complete the ladder-type piezoelectric component A.

The base plate 24 used in the ladder-type ceramic filter as described above is provided with the node pressing portion 25 over the entire length, and the terminal lead-out holes 26, 27, 26 are only opened in the central portion. Therefore, for example, an extruded product having the sectional shapes of the node pressing portion 25 and the base plate 24 is continuously extruded, and the extruded product is cut into a certain size by a press machine and at the same time the terminal drawing holes 26, 27, Mass production can be easily performed by punching out 26. Further, even when molding by injection molding, the shape of the molding die can be simplified.

[0031]

[Effect of the device]

 According to the present invention, since it is not necessary to draw the lead portion from end to end in the arrangement direction inside the case, the portion extending in parallel with the arrangement direction of the lead portion is less likely to bend due to external force applied during assembly, etc. It is possible to prevent the part from coming into contact with another terminal plate, a piezoelectric element, or the like to cause a short circuit.

Therefore, it is not necessary to provide a lead storage groove for preventing a short circuit on the inner surface of the base plate as in the conventional case, and the shape of the base plate can be simplified. Therefore, when the base plate is resin-molded, for example, the resin molding of the base plate can be facilitated, molding defects are reduced, and the die cost is reduced.

Further, since the base plate can be formed in a symmetrical shape, it is possible to eliminate the directionality when inserting the base plate into the case and facilitate the automation of the assembling work.

Further, since the node pressing portion is provided on the inner surface of the base plate so that the node pressing portion is brought into contact with the end surface of each piezoelectric element, the piezoelectric element can be pressed so as not to move in the case. The characteristics of the piezoelectric element can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a ladder type ceramic filter according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a piezoelectric unit incorporated in the ladder-type ceramic filter of the above.

FIG. 3 is a perspective view showing a base plate used in the above-mentioned embodiment.

FIG. 4 is an equivalent circuit diagram of a ladder type ceramic filter.

FIG. 5 is a sectional view showing a ladder type ceramic filter according to a conventional example.

FIG. 6 is a perspective view showing a piezoelectric unit incorporated in a conventional ladder-type ceramic filter.

FIG. 7 is a perspective view showing a base plate used in the above-mentioned embodiment.

[Explanation of symbols]

 A Ladder type ceramic filter B Piezoelectric unit 1 Input terminal plate 2 Series piezoelectric element 5 Parallel piezoelectric element 6 Ground terminal plate 7 Parallel piezoelectric element 8 Output terminal plate 9 Series piezoelectric element 12 Ground terminal plate lead part 15 Input terminal plate lead part 18 Leads of output terminal board 23 Case 24 Base board 25 Node retainer 26, 27 Terminal lead-out hole

Claims (2)

[Scope of utility model registration request] 1. A piezoelectric unit in which a plurality of piezoelectric elements and three or more terminal plates are arranged to form a ladder type circuit is housed in a case, an opening of the case is closed by a base plate, and each of the terminal plates is formed. In the piezoelectric component in which the lead part of the terminal plate penetrates through the base plate and is drawn out of the case, the lead parts of the terminal plates other than the terminal plates located at substantially the center in the arrangement direction of the three or more terminal plates are bent. Thus, the lead portions of all the terminal plates are aligned in a line in the direction orthogonal to the arrangement direction in the approximate center of the base plate, and three or more terminal lead-out holes are formed in a line in the approximate center of the base plate. A ladder-type piezoelectric component, wherein the lead portions of the respective terminal plates are inserted. 2. The ladder-type piezoelectric component according to claim 1, wherein a node pressing portion that is substantially parallel to the arrangement direction is provided on the inner surface of the base plate.