JP4153191B2 - Piezoelectric transformer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piezoelectric transformer used for a high voltage power source such as an inverter for lighting a liquid crystal display, a DC-DC converter for power supply, an AC-DC converter, an air cleaner, and the like.
[0002]
[Prior art]
There are various types of piezoelectric transformer bodies. As a general one, a so-called second-order Rosen-type piezoelectric transformer body 20 as shown in FIG. 5 is known.
[0003]
The piezoelectric transformer main body 20 is provided with an input-side primary electrode 22 on each of the front and back surfaces of one half of an elongated rectangular piezoelectric ceramic plate 21, and an output-side secondary electrode 23 at the other half-side end. The primary side is polarized in the thickness direction to form a drive unit, and the secondary side is polarized in the length direction to form an output unit. Lead wires 11 and 12 are connected to each primary electrode 22, and output lead wire 13 is connected to secondary electrode 23.
[0004]
When a voltage having a natural resonance frequency determined by the length dimension is input to the primary side, strong mechanical vibration is generated in the piezoelectric ceramic plate 21 by the inverse piezoelectric effect, and a high voltage corresponding to the vibration is generated by the piezoelectric effect on the secondary side. It is comprised so that it may be output from.
[0005]
As shown in FIG. 6, the piezoelectric ceramic plate 21 is housed in a resin-made rectangular box-shaped piezoelectric transformer case 1 for protection and mounting on the substrate. For convenience of explanation, the lead wires 11 to 13 and the electrodes are not shown in FIG.
[0006]
When the piezoelectric transformer case 1 is housed, the piezoelectric ceramic plate 21 is mechanically vibrated and an output is generated by the piezoelectric effect. If the vibration is inhibited, the performance is impaired. The adhesive 24 is applied in advance to the corresponding inner surface position of the piezoelectric transformer case 1, the piezoelectric ceramic plate 21 is housed and fixed in the piezoelectric transformer case 1, and the lead wires 11 and 12 are connected to the node portions to improve efficiency.・ We try to minimize the performance.
[0007]
In use, the bottom surface side of the piezoelectric transformer case 1 is mounted on the substrate p via the terminals 8 ', 10' and the like.
[0008]
[Problems to be solved by the invention]
In this case, the piezoelectric transformer for causing mechanical vibrations, the gap between the lower surface of the side plate and the end plate of the substrate p and the piezoelectric transformer case 1 which may cause noise occurs as a slight, there is a problem that.
[0009]
The present invention has been proposed in view of the above, and an object of the present invention is to provide a piezoelectric transformer in which a gap is formed between a substrate and a piezoelectric transformer case to prevent noise.
[0010]
[Means for Solving the Problems]
The present invention is characterized in that in the piezoelectric transformer mounted on the substrate p, the gap between the lower surface of the main body of the piezoelectric transformer case 1 and the substrate p is set to a distance at which no noise is generated when the piezoelectric transformer is driven.
[0011]
That is, the terminal provided in the piezoelectric transformer case 1 is extended downward, and the distance between the contact at the bottom of the terminal and the lower surfaces of the side plates 3 and 4 and the end plates 5 and 6 of the piezoelectric transformer case 1 is at least 0.05 mm or more. It is said. That is, in the present invention , in the piezoelectric transformer mounted on the substrate p , the piezoelectric transformer main body 20 is accommodated in the piezoelectric transformer case 1, and the piezoelectric transformer main body 20 is fixed to the top plate 2 side of the piezoelectric transformer case 1. In addition , a gap is provided between the lower surfaces of the side plates 3 and 4 and the end plates 5 and 6 of the piezoelectric transformer case 1 and the substrate p. The gap is at least 0.05 mm.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, legs of surface mounting terminals 8 to 9 provided in the piezoelectric transformer case 1 are extended downward, and a gap is formed between the substrate p and the piezoelectric transformer case 1 by effectively using the terminals 8 to 9. It is formed so that no sound is generated.
[0013]
【Example】
1A is a side view of the piezoelectric transformer of the present invention mounted on a substrate p, FIG. 1B is an enlarged explanatory view of the main part, FIG. 2 is a bottom view, FIG. 3 is a plan view, and FIG. a) shows a left end surface (b) shows a right end surface.
[0014]
In these drawings, reference numeral 1 denotes a resin-made box-shaped piezoelectric transformer case. In the piezoelectric transformer case 1, a piezoelectric transformer body 20 as shown in FIG. 5 is accommodated and attached via an adhesive 24. A piezoelectric transformer is configured.
[0015]
The piezoelectric transformer case 1 is flat and has a rectangular top plate 2, first and second side plates 3 and 4 formed on the long side of the top plate 2, and the short side of the top plate 2. The first and second end plates 5 and 6 are respectively formed, and an opening 7 is formed on the bottom surface.
[0016]
The first end plate 5 is provided with a first terminal 8, and the first side plate 3 is provided with a second terminal 9 at a substantially central portion, and the second end plate 6 is provided with a third terminal. Terminal 10 is provided.
[0017]
The first terminal 8 is connected to the other end of the first lead wire 11 having one end connected to a primary electrode 22 provided on one half of one surface of the piezoelectric transformer body 20.
[0018]
The second terminal 9 is connected to the other end of the second lead wire 12 whose one end is connected to the other primary electrode 22 of the piezoelectric transformer body 20.
[0019]
The third terminal 10 is connected to the other end of the third lead wire 13 having one end connected to the secondary electrode 23 provided at the other half end of one surface of the piezoelectric transformer body 20.
[0020]
Further, the first side plate 3 of the case 1 is formed with a notch 14 for leading out the first lead wire 11 having one end connected to the substantially central portion of the primary electrode 22, and the lead wire drawn out. Guide protrusions 15 and 16 are formed for guiding 11 to the first terminal 8 side. The leading end of the lead wire 11 is connected to the first terminal 8 via the solder a.
[0021]
Further, a rib 17 is formed at substantially the center of the first side plate 3 of the case 1, and a part of the second terminal 9 is embedded in the lower part of the rib 17, whereby the second terminal 9 is connected to the case 1. 1 is attached.
[0022]
A window-shaped notch 18 is formed in the vicinity of the rib 17 so as to lead out the second lead wire 12 to the outside. The second lead wire is drawn out from the notch 18, and the end portion of the solder a To the second terminal 9.
[0023]
1A and 2, the right end portion of the first side plate 3 of the piezoelectric transformer case 1 is slightly bulged outwardly, and the third lead wire 13 having one end connected to the secondary electrode 23 is routed around. A space 19 is formed and drawn out through the notch 19 a, and the other end of the third lead wire 13 is connected to the third terminal 10.
[0024]
Ribs 5a are formed substantially at the center of the first end plate 5 of the piezoelectric transformer case 1 (see FIG. 1B and FIG. 4A), and the lower portions of the ribs 5a are the side plates 3 of the piezoelectric transformer case 1. 4 and the lower surfaces of the end plates 5 and 6 are extended downward. Further, a part (not shown) of the first terminal 8 is buried in a lower part of the rib 5a as is well known, and the first terminal 8 is attached.
[0025]
The lower surface of the first terminal 8 serves as a contact 8a for surface mounting, but extends to the lower surface of the rib 5a, and the contact 8a located on each side plate 3, 4 or end plate 5, 6 of the piezoelectric transformer case 1 is provided. It is provided at a position at least 0.05 mm away from the lower surface. A part of the third terminal 10 is also embedded in the rib 6 a of the second end plate 6 in the same manner, and is fixed in the same manner as the first terminal 8.
[0026]
Further, the contact 9a of the second terminal 9 is also provided at a position separated by at least 0.05 mm from the lower surfaces of the side plates 3, 4 and the like of the piezoelectric transformer case 1.
[0027]
Therefore, when the piezoelectric transformer is mounted on the substrate p, the distance between the lower surface of the main body of the piezoelectric transformer case 1 in which the piezoelectric transformer main body 21 is housed and the substrate p is at least 0.05 mm.
[0028]
This dimension is the distance that can effectively prevent the noise generated when the piezoelectric transformer is mounted, and is the distance calculated from the experimental results of several prototypes with different distances. It is suitable in the range of -0.4 mm. In addition, it is not preferable from the viewpoint of reducing the height if a gap is formed more than necessary.
[0029]
Note that ribs 8b to 10b bent upward are formed on both sides of the outer end portions of the contacts 8a to 10a of the first to third terminals 8 to 10, respectively, and the first to third leads are formed inside thereof. The other ends of the wires 11 to 13 are guided and connected by soldering a.
[0030]
【The invention's effect】
As described above, according to the present invention, a gap of at least 0.05 mm or more is provided between the lower surfaces of the side plates 3 and 4 and the end plates 5 and 6 of the piezoelectric transformer case surface-mounted on the substrate p and the substrate p. Therefore, it is possible to prevent the noise generated when the piezoelectric transformer is driven.
[Brief description of the drawings]
1A is a side view of a piezoelectric transformer according to an embodiment of the present invention, and FIG. 1B is a partially enlarged explanatory view thereof.
FIG. 2 is a bottom view of the piezoelectric transformer according to the embodiment.
FIG. 3 is a plan view of the same.
4A is a left end view, and FIG. 4B is a right end view. FIG. 5 is a perspective view of a general piezoelectric transformer.
FIG. 6 shows a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Case 2 Top plate 3 1st side plate 4 2nd side plate 5 1st end plate 6 2nd end plate 7 Opening part 8 1st terminal 8a Contact 8b Rib 9 2nd terminal 9a Contact 9b Rib 10 1st 3 terminal 10a contact 10b rib 11 first lead wire 12 second lead wire 13 third lead wire 14 notch 15, 16 guide protrusion 17 rib 18 notch 19 space 19a notch a solder

Claims (2)

In a piezoelectric transformer mounted on a substrate (p) , a piezoelectric transformer body (20) is accommodated in a piezoelectric transformer case (1), and the piezoelectric transformer body (20) is a top plate of the piezoelectric transformer case (1). (2) It is fixed to the side, and a gap is provided between the lower surface of each side plate (3, 4) and each end plate (5, 6) of the piezoelectric transformer case (1) and the substrate (p). Piezoelectric transformer.   The piezoelectric transformer according to claim 1, wherein the gap is at least 0.05 mm or more.

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