JPH0749354A - Piezoelectric vibration sensor - Google Patents

Abstract

PURPOSE:To miniaturize a piezoelectric vibration sensor. CONSTITUTION:A piezoelectric vibration sensor comprises a piezoelectric body 31, a first electrode and second electrode disposed on both surfaces of the piezoelectric body 31, a substrate 32 to which an electrode 46 for electric circuit connected to the first electrode is provided, and a load body 33 installed in the second electrode. The second electrode has a pair of split electrodes for X axis disposed on an X axis and a pair of split electrodes for Y axis disposed on an Y axis. Electrodes for connection disposed on the X axis or the Y axis are stacked through insulating plates between the second electrode 40 and the load body 33. In these electrodes for connection and insulating plates, through holes penetrating these are formed. Connecting parts for electrically connecting the pair of split electrodes for X axis or the pair of split electrodes for Y axis with electrodes for connection are provided in the through holes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric vibration sensor used for monitoring a rotating machine, an impact switch, etc., and more particularly to a piezoelectric vibration sensor having improved mass productivity.

[0002]

2. Description of the Related Art Generally, a piezoelectric vibration sensor is designed to detect vibrations in only one direction, and cannot detect vibrations in other directions. Vibration has a direction and a magnitude, and it is desirable for a vibration sensor to be able to evaluate both of them. Therefore, in order to evaluate all vibrations, the conventional vibration sensor has a structure in which at least three sensors 1, 2 and 3 are combined so that their main sensitivity axes are orthogonal to each other, as shown in FIG. It was necessary to install three detectors so that they were orthogonal to each other. According to such a vibration sensor, it has an extremely complicated structure, becomes costly, requires a large space, and lacks versatility.

The vibration sensor proposed there is, as shown in FIG. 11, a single piezoelectric body 5 mounted on a pedestal.
And a load body (not shown) fixed to the upper surface of the piezoelectric body 5.
And a first electrode 6 provided on the back surface of the piezoelectric body 5 and a second electrode 4 provided on the front surface of the piezoelectric body 5. The first electrode 6 is provided over the entire back surface of the piezoelectric body 5. The second electrode 4 is formed on the surface of the piezoelectric body 5 in a divided manner, and a straight line which is orthogonal to the surface of the piezoelectric body 5 and which passes through substantially the center of the piezoelectric body 5 is the z axis, and the second electrodes 4 are perpendicular to the z axis. A z-axis electrode 7 for detecting displacement in the z-axis direction when two orthogonal straight lines are respectively defined as the x-axis and the y-axis,
It is composed of x-axis electrodes 8 and 9 that detect displacement in the x-axis direction, and y-axis electrodes 10 and 11 that detect displacement in the y-axis direction.

The z-axis electrode 7 is formed in a substantially point-symmetrical shape about the z-axis. x-axis electrodes 8 and 9 are z
A pair of electrodes are formed around the shaft electrode 7 and are line-symmetrical to each other with respect to the y-axis and have the same shape. The y-axis electrodes 10 and 11 are formed around the z-axis electrode 7,
A pair is formed in positions that are line-symmetric with respect to the x-axis and have the same shape. The center of gravity of this vibration sensor is located on an axis passing through the center of the surface of the piezoelectric body 5.

In such a vibration sensor, as shown in FIG. 12, the z-axis component of vibration is measured based on the potential difference Vz generated between the first electrode 6 and the z-axis electrode 7. The component of the vibration in the x-axis direction is the potential difference between the potential difference generated between the one x-axis electrode 8 and the first electrode 6 and the potential difference generated between the other x-axis electrode 9 and the first electrode 6. Vx
It is measured based on. The component of the vibration in the y-axis direction is the difference between the potential difference generated between the one y-axis electrode 10 and the first electrode 6 and the potential difference generated between the other y-axis electrode 11 and the first electrode 6. It is measured based on Vy.

[0006]

However, except for a surface perpendicular to the piezoelectric body 5, one of the input signals of each axis cannot be grounded when measuring the output in the other x and y axis directions. It was difficult to measure with a container. In a general-purpose measuring instrument, one side of the normal input signal is grounded, and when measuring the output of the vibration sensor, the output measurement in the x-axis and y-axis directions must not be grounded by a special method. This is because it must be done.

Therefore, the inventors of the present invention have shown in FIGS.
As shown in Fig. 4, a piezoelectric vibration sensor having a high versatility and capable of separately measuring directional vibration has been proposed (Japanese Patent Application No. 3-254807). This piezoelectric type vibration sensor has a substrate 15
A piezoelectric body 16 and a load body 17 are laminated on top. In the piezoelectric body 16, as shown in FIG. 14, y-axis split electrodes 18, 19 are formed on the lower surface in line symmetry with respect to the x-axis and with point symmetry with respect to the intersection of the x-axis and the y-axis. The split electrode 20 for the x-axis is formed in line symmetry with respect to the y-axis and including the intersection, and in point symmetry with respect to the intersection. On the other hand, the y-axis divided electrode 21 is formed on the upper surface of the piezoelectric body 16 so as to be line-symmetrical to the x-axis and include the intersection, and to be symmetrical about the intersection.
The split electrodes 22 and 23 for the x-axis are formed line-symmetrically with respect to the y-axis and point-symmetrically with respect to the intersection. In such a piezoelectric vibration sensor, since no electrode shared by the x-axis and the y-axis is provided, one of the inputs can be grounded to the measuring instrument, and the measurement can be stabilized.

In the piezoelectric vibration sensor, since only one electrode is formed on the piezoelectric body 16, the output in the x direction is taken out from one surface of the piezoelectric body 16 and the output in the y direction is produced in the piezoelectric body 16. Had been taken from the other side of. Therefore, as shown in FIG. 13, a spacer 26 is required to take out the lead wire 25 from the x-axis or y-axis split electrode, and the spacer 26 is provided between the piezoelectric body 16 and the load body 17. There was a case. In such a case, there is a problem that the spacer 26 is formed thick in order to take out the lead wire 25 from each electrode, and the piezoelectric vibration sensor is formed thick. Further, a device such as a wire bonder for taking out the lead wire 25 from the x-axis or y-axis divided electrode is required, and a lead wire take-out step is required, which complicates the manufacturing work of the piezoelectric vibration sensor. It was

The present invention effectively solves the above-mentioned problems. The piezoelectric vibration sensor can be miniaturized, the versatility of the piezoelectric vibration sensor can be maintained, and the manufacturing workability of the piezoelectric vibration sensor can be improved. An object is to provide a vibration sensor.

[0010]

A piezoelectric vibration sensor of the present invention is provided with a piezoelectric body, a pair of multi-layer laminated electrodes disposed on both surfaces of the piezoelectric body, and one of these multi-layer laminated electrodes. And a load body attached to the other of the multi-layer laminated electrodes, the other multi-layer laminated electrode detects the displacement of the x-axis in the plane of the piezoelectric body. A pair of split electrodes for the x-axis and a pair of y for detecting the displacement of the y-axis.
A split electrode for the axis, and a split electrode for the x-axis and y
Between the split electrode for the shaft and the load body, the connecting electrodes arranged on the x-axis or the y-axis are stacked via the insulating plate,
A through hole is formed through the connecting electrode and the insulating plate, and the through electrode is electrically connected to the pair of x-axis divided electrodes or the pair of y-axis divided electrodes and the connecting electrode. It is characterized in that a connecting portion for electrically connecting is provided.

The connecting electrode may be composed of two layers of electrodes via an insulating plate. On one of these two layers of electrodes, x including the intersection of the x axis and the y axis at the center of the plane of the piezoelectric body on the x axis.
The electrode for axis connection may be formed, and on the other hand, the electrode for y axis connection including the intersection may be formed on the y axis. A pair of x-axis divided electrodes are electrically connected to the x-axis connecting electrode via a connecting portion, and a pair of y-axis dividing electrodes are electrically connected to the y-axis connecting electrode via a connecting portion. It is connected to the.

On the other hand, the connecting electrode is arranged on either the x-axis or the y-axis and has a strip-shaped electrode including the intersection.
A pair of L-shaped electrodes may be provided on the other of the x-axis and the y-axis, and the L-shaped electrodes may be spaced apart from the strip electrodes. Either one of the pair of x-axis or y-axis split electrodes of the second electrode is connected to the strip electrode via the connecting portion, and the L-shaped electrode is connected to the pair of x-axis of the second electrode. For axes,
Alternatively, the other of the y-axis divided electrodes is connected via the connecting portion.

[0013]

In the piezoelectric vibration sensor of the present invention, the charges generated on both surfaces of the piezoelectric body are transmitted to the pair of multi-layer laminated electrodes. The electric charge detected by one of these multi-layer laminated electrodes is transmitted to the electric circuit electrode. On the other side of the multi-layer laminated electrode, each x-axis split electrode is electrically connected to a connecting portion, and this connecting portion is connected to the connecting electrode through a through hole,
A pair of x-axis split electrodes are connected. On the other hand, each y-axis divided electrode is electrically connected to the connecting portion, and this connecting portion is connected to the connecting electrode through the through hole,
A pair of y-axis divided electrodes are connected. Since these connecting electrodes are stacked on the piezoelectric body via the insulating plate, a short circuit between the adjacent x-axis divided electrode and y-axis divided electrode is prevented.

When the connecting electrode is composed of two layers of electrodes, one pair of electrodes for x-axis connection of one of these two layers of electrodes connects the pair of divided electrodes for x-axis, and the other electrode for connection of y-axis forms a pair of electrodes. The divided electrodes for y-axis are connected.

On the other hand, if the connecting electrode is composed of a strip electrode and an L-shaped electrode, the strip electrode connects either one of the pair of x-axis or y-axis split electrodes of the second electrode, and L
The V-shaped electrode connects the other.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the piezoelectric vibration sensor of the present invention will be described below with reference to FIGS.
As shown in FIG. 1, reference numeral 30 is a piezoelectric vibration sensor. The piezoelectric vibration sensor 30 is provided with a piezoelectric body 31 and a back surface of the piezoelectric body 31, and an electric circuit electrode 46 is provided. It includes a substrate 32 and a load body 33 arranged on the surface of the piezoelectric body 31. Between the substrate 32 and the load body 33, as shown in the exploded view of FIG.
4 (multilayer multilayer electrode), piezoelectric body 31, and three-layer laminated electrode 3
5 (multilayer multilayer electrode) is an electrode 46 for electric circuit of the substrate 32.
Stacked on top.

The two-layer laminated electrode 34, as shown in FIG.
An output electrode 36 connected to the electric circuit electrode 46 on the substrate 32, an insulator 37 such as a polyimide film disposed on the output electrode 36, and a first electrode disposed on the insulator 37. One electrode 38 is stacked. When the two straight lines orthogonal to each other with the center of the back surface of the piezoelectric body 31 as an intersection are defined as the x axis and the y axis, the first electrodes 38 are arranged in a pair on the x axis and are point-symmetric with respect to the intersection. It has a pair of divided electrodes 38a for the x-axis, and a pair of divided electrodes 38b for the y-axis, which are arranged on the y-axis in a pair symmetrically with respect to the intersection. The output electrode 36 has a pair of x-axis divided electrodes 36a and a pair of y-axis divided electrodes 36b facing the respective divided electrodes of the first electrode 38. The output electrode 36, the first electrode 38, and the insulating plate 37 have through-holes 36c, 37c, and 3 penetrating them.
8c is formed in the center of each divided electrode.
Metal plating layers (connecting portions) are formed on the peripheral walls of the through holes 36c, 37c, 38c, and the divided electrodes facing each other are connected via the metal plating layers.

On the other hand, in the three-layer laminated electrode 35, as shown in an exploded view in FIG. 4, the second electrode 40 provided on the piezoelectric body 31 and the second electrode 40 are provided. Insulator 37
An intermediate layer electrode (connection electrode) 41 disposed on the insulator 37, and an insulator 3 disposed on the intermediate layer electrode 41.
7, an upper layer electrode (connection electrode) 42 arranged on the insulator 37, and an insulator 37 arranged on the upper layer electrode 42 are stacked. The three-layer laminated electrode 35 has a through hole 40 penetrating the second electrode 40, the middle layer electrode 41, the upper layer electrode 42, and the insulator 37.
c, 41c, 42c, 37c are formed respectively.

In the second electrode 40, when two lines orthogonal to each other with the center of the surface of the piezoelectric body 31 as an intersection point are taken as the x-axis and the y-axis, one pair is arranged on the x-axis, and with respect to the intersection point. It has a pair of x-axis divided electrodes 40a arranged point-symmetrically, and a pair of y-axis divided electrodes 40b arranged on the y-axis point-symmetrically with respect to the intersection. The x-axis split electrode 40a and the y-axis split electrode 40b of the second electrode 40 are formed by sandwiching the piezoelectric body 31 between the x-axis split electrode 38a and the y-axis split electrode 38b of the first electrode 38. They are arranged to face each other.

The middle-layer electrode 41 has a pair of x-axis connecting electrodes 41a arranged at intervals on the x-axis and a y-axis connecting electrode 41b arranged on the y-axis and including the intersection. The x-axis connecting electrode 41a and the y-axis connecting electrode 41b are arranged with a space therebetween so as not to contact each other. The upper layer electrode 42 is formed in a shape obtained by rotating the middle layer electrode 41 by 90 degrees, and is arranged on the x axis, and an x axis connecting electrode 42a including the intersection and a pair arranged at a distance on the y axis. The y
And an x-axis connecting electrode 4b.
2a and each y-axis connecting electrode 42b are arranged with an interval so as not to contact each other.

That is, the y-axis connecting electrode 41b of the middle-layer electrode 41 and the x-axis connecting electrode 42a of the upper-layer electrode 42 extend in a direction intersecting with each other, and the y-axis connecting electrode 41b of the middle-layer electrode 41 serves as a second electrode. Pair of y-axis divided electrodes 4 of the electrode 40
0b is the lower part of the through hole 37c, 37c of the insulator 37
Through the metal plating layer, the pair of x-axis split electrodes 40a of the second electrode 40 in the x-axis connecting electrode 42a of the upper layer electrode 42 is the through hole 37c of the upper insulator 37,
It is short-circuited via the metal plating layer 37c.

The substrate 32 is a substrate body 45 made of fiber reinforced resin (FRP) such as glass fiber reinforced epoxy resin obtained by impregnating epoxy resin with glass fiber, and the substrate body 4
5, the output electrode 3 of the two-layer laminated electrode 34 provided on the surface of
6 and an electric circuit electrode 46 connected to the circuit 6. The electric circuit electrode 46 is formed by copper plating or the like, and is arranged at a position facing each divided electrode of the output electrode 36.

As the piezoelectric body 31, a synthetic resin piezoelectric material such as polyvinylidene fluoride, polyvinyl fluoride, a copolymer of tetrafluoroethylene and trifluoroethylene, or a perovskite such as metal titanate or metal zirconate is used. A ceramic piezoelectric material having a structure can be used.

Next, a method of manufacturing the piezoelectric vibration sensor will be described. The two-layer laminated electrode 34 and the three-layer laminated electrode 35 are assembled in advance. By plating the through holes 36c to 38c of the two-layer laminated electrode 34 and the through holes 40c to 42c and 37c of the three-layer laminated electrode 35, the through holes 36c to 38c and 40c are plated.
A metal plating layer is provided on the peripheral wall of 42c. Then, the two-layer laminated electrode 34 and the three-layer laminated electrode 35 are attached to both surfaces of the piezoelectric body 31, and the two-layer laminated electrode 34 is attached on the electric circuit electrode 46 of the substrate 32. On the other hand, by attaching the load body 33 onto the three-layer laminated electrode 35, the piezoelectric vibration sensor is assembled.

In the piezoelectric type vibration sensor 30 as described above, the charges generated on both surfaces of the piezoelectric body 31 are transmitted to the two-layer laminated electrode 34 and the three-layer laminated electrode 35. In the two-layer laminated electrode 34, the charges on the back surface of the piezoelectric body 31 are transferred to the x-axis divided electrode 38a and the y-axis divided electrode 38b of the first electrode 38, and these x
The electric charges of the axial and y-axis split electrodes 38a and 38b are transferred to the x-axis split electrode 36a and the y-axis split electrode 36b of the output electrode 36 through the metal plating layers in the through holes 38c, 37c and 36c, respectively. To be done. These output electrodes 36
The charges of the x-axis and y-axis split electrodes 36a and 36b are directly transmitted to the electric circuit electrode 46.

On the other hand, in the three-layer laminated electrode 35, charges on the surface of the piezoelectric body 31 are transmitted to the x-axis divided electrode 40a and the y-axis divided electrode 40b of the second electrode 40, and these x-axis and y-axis are divided. The charge of the split electrodes 40a, 40b for each through hole 40
It is transmitted to the middle layer electrode 41 and the upper layer electrode 42 via the metal plating layers in c, 37c, 41c, 37c and 42c, respectively. Here, the pair of y-axis divided electrodes 40b of the second electrode 40 are short-circuited by the y-axis connecting electrode 41b of the middle layer electrode 41, and the pair of the second electrode 40 is paired by the x-axis connecting electrode 42a of the upper layer electrode 42. The x-axis split electrode 40a is short-circuited. Therefore, each of the x-axis divided electrodes 40a of the second electrode 40 in the three-layer laminated electrode 35 is short-circuited, and each of the y-axis divided electrodes 40b is short-circuited.

According to such a piezoelectric vibration sensor 30, since it has the piezoelectric body 31, and the two-layer laminated electrode 34 and the three-layer laminated electrode 35 arranged on both surfaces of the piezoelectric body 31,
The charges generated on both surfaces of the piezoelectric body 31 are transmitted to the two-layer laminated electrode 34 and the three-layer laminated electrode 35, respectively. Since the two-layer laminated electrode 34 has a configuration in which the output electrode 36, the insulator 37, and the first electrode 38 are stacked, the output electrode 36
The insulator 37 prevents the first electrode 38 and the first electrode 38 from being directly connected.

The first electrode 38 is a split electrode 38a for the x-axis.
And the y-axis split electrode 38b, the charge of the piezoelectric body 31 is detected by the x-axis split electrode 38a.
The vibration in the axial direction is detected, and the electric charge of the piezoelectric body 31 is detected by the y-axis divided electrode 38b, whereby the vibration in the y-axis direction is detected. The divided electrodes 38a and 38b for the x-axis and the y-axis of the first electrode 38 are for the x-axis of the output electrode 36, and y.
The divided electrodes 36a and 36b for shafts are respectively connected via metal plating layers.

Since the first electrode 38 is disposed on the back surface of the piezoelectric body 31 and the output electrode 36 is connected to the electric circuit electrode 46, the charge generated on the back surface of the piezoelectric body 31 is applied to the first electrode. From each divided electrode 38, a metal plating layer, an output electrode 36
Is transmitted to each divided electrode of the electric circuit electrode 46 via. Therefore, it is possible to eliminate the need to connect the electric charges on the back surface of the piezoelectric body 31 to the electric circuit electrode 46 by a lead wire or the like, and to eliminate a device such as a wire bonder. Therefore, the whole can be made thin.

The pair of x-axis divided electrodes 40a, 40a of the second electrode 40 are electrically connected to each other, and the second electrode 4
Since the pair of y-axis split electrodes 40b, 40b of 0 are electrically connected, the pair of split electrodes of the second electrode 40 can be short-circuited, and the work of attaching a lead wire to each of these split electrodes can be omitted. Since a device such as a wire bonder can be eliminated, the manufacturing cost of the piezoelectric vibration sensor can be reduced. Therefore, since the lead wire is not necessary, it is possible to eliminate the connection failure due to the disconnection of the lead wire, and the spacer for taking out the lead wire can be eliminated, so that the piezoelectric vibration sensor can be downsized.

Experimental Example A piezoelectric vibration sensor having the structure shown in FIGS. 1 to 4 was manufactured. As a load body, 3 mm x 3 m
A rectangular parallelepiped brass having a size of m × 1 mmt is used, and a piezoelectric body having a size of P of 3 mm × 3 mm × 0.5 mmt is used.
ZT (lead zirconate titanate) was used. Then, the two-layer laminated electrode uses a copper foil as an electrode and a polyimide film as an insulator, and has a size of 3 mm × 3 mm ×
It was formed to 0.06 mmt. The three-layer laminated electrode is made of copper foil and polyimide film and has a size of 3 mm × 3 mm ×
It was formed to 0.1 mmt. The piezoelectric body was sandwiched between the two-layer laminated electrode and the three-layer laminated electrode, and the two-layer laminated electrode was fixed to the electric circuit electrode on the substrate by soldering.

Comparative Example A piezoelectric vibration sensor shown in FIGS. 13 to 14 was manufactured. Here, as the load body and the piezoelectric body, the same ones as in the above embodiment were used, and a spacer for taking out a lead wire was inserted between the load body and the piezoelectric body. This spacer was formed of a fiber-reinforced resin having a glass fiber impregnated with an epoxy resin and a thickness of 1 mm. In manufacturing such a piezoelectric vibration sensor, one end of a lead wire was connected to an electrode on a piezoelectric body, and the other end of this lead wire was connected to an electric circuit provided on a substrate. On the other hand, on the lower surface of the piezoelectric body, the electrodes on the lower side of the piezoelectric body were directly fixed to the electric circuit electrodes provided on the substrate with solder, and the other portions were fixed with epoxy resin.

100 piezoelectric vibration sensors were made for each of the experimental example and the comparative example, and the performance of these piezoelectric vibration sensors was evaluated. In the experimental example, the variation in sensitivity between the two directions was within 10% for all prototypes. On the other hand, in the comparative example, the variation of sensitivity was within 10% in 80% of the whole. It is considered that this is because the experimental example used only solder for fixing to the substrate, whereas the comparative example used different adhesives such as solder and epoxy resin for fixing to the substrate.

As a result of estimating the manufacturing cost per piezoelectric vibration sensor, the experimental example is about 90% of the comparative example.
Therefore, the piezoelectric vibration sensor of the experimental example can be manufactured at a lower cost than the comparative example. Further, when comparing the heights of the piezoelectric vibration sensors, the height of the piezoelectric vibration sensor of the example was formed to about 1.7 mm, and the height of the piezoelectric vibration sensor of the comparative example was formed to 2.7 mm. For this reason, the piezoelectric vibration sensor of the experimental example is formed to be much thinner than the comparative example, and is suitable for downsizing.

<Modification> In the above embodiment, the output electrode 36 of the two-layer laminated electrode 34 is divided into four parts, but may be divided into three parts as shown in FIG. In the three-divided output electrode 50, a pair of adjacent x-axis divided electrodes and y-axis divided electrodes of the four-divided output electrodes are integrally formed continuously. On the other hand, in the above-described embodiment, the electric circuit electrode 46 on the substrate 32 is divided into a plurality of parts, and the output electrode 36 of the two-layer laminated electrode 34 is connected to each of the divided electric circuit electrodes 46. The output electrode 36 may be removed, and the first electrode 38 of the two-layer laminated electrode 34 may be directly connected to each of the divided electric circuit electrodes 46 by a metal plating layer.

Further, in the above embodiment, the three-layer laminated electrode 3
5, the middle layer electrode 41 and the upper layer electrode 42 were formed.
As shown in, a single-layer short-circuit electrode 51 (connection electrode)
May be formed. The short-circuiting electrode 51 is arranged on either the x-axis or the y-axis, and the strip electrode 51a including the intersection of the x-axis and the y-axis and the pair of short-circuiting electrodes 51 are arranged on the other of the x-axis and the y-axis. The L-shaped electrode 51b is integrally formed continuously along the edge of the piezoelectric body 31.
Between the strip-shaped electrode 51a and the L-shaped electrode 51b,
They are spaced to prevent them from touching each other. Then, the strip electrode 51a is the second electrode 4
It is electrically connected to either one of the pair of split electrodes 40a for the x-axis or split electrode 40b for the y-axis of 0 through a metal plating layer. The L-shaped electrode 51b is electrically connected to the other of the pair of x-axis divided electrodes 40a or y-axis divided electrode 40b of the second electrode 40 via a metal plating layer.

By thus using the single-layer short-circuit electrode 51 instead of the middle-layer electrode 41 and the upper-layer electrode 42, the middle-layer electrode 41 and the upper-layer electrode 42 and the insulating plate 37 disposed between them are Can be eliminated, and the thickness of the three-layer laminated electrode 35 can be reduced.

Further, in the above-mentioned embodiment, the second electrode 40 is divided and formed at each of the four corners of the square piezoelectric body 31, but FIG.
As shown in FIG.
It may be divided into four parts with the diagonal line as a boundary. In the second electrode 55, a through hole 55c is formed at the center of each divided electrode. In such a case, in the three-layer laminated electrode on the piezoelectric body, as shown in FIG. 8, the middle-layer electrode 56 is divided into three strips along one of the x-axis and the y-axis, and shown in FIG. As described above, the upper layer electrode 57 may be divided into three strips along the other of the x axis and the y axis.

[0039]

As described above, according to the piezoelectric vibration sensor of the present invention, the piezoelectric body, the pair of multi-layer laminated electrodes disposed on both surfaces of the piezoelectric body, and the multi-layer laminated electrodes Since the substrate provided with the electric circuit electrode connected to one side and the load body attached to the other side of the multilayer laminated electrode are provided, the charges generated on both surfaces of the piezoelectric body are transferred to the multilayer multilayer electrode. Are transmitted to the electrodes for electric circuits. The multi-layer laminated electrode mounted between the piezoelectric body and the load body is a pair of x-axis split electrodes for detecting the displacement of the x-axis in the plane of the piezoelectric body, and a pair of y for detecting the displacement of the y-axis. A split electrode for the axis and a split electrode for the x-axis and the split electrode for the y-axis and the load body, and a connecting electrode disposed on the x-axis or the y-axis via an insulating plate. Through-holes are stacked in the connecting electrodes and the insulating plate to penetrate them, and the pair of x-axis divided electrodes or the pair of y-axis divided electrodes and connecting electrodes are formed in the through holes. Since the configuration is such that a connection portion for electrically connecting the and is provided, the pair of split electrodes for the x-axis is electrically connected via the connection portion and the connection electrode, or connected to the connection portion. The pair of y-axis divided electrodes are electrically connected to each other via the working electrode. Therefore, since the x-axis divided electrode or the y-axis divided electrode can be short-circuited, the work of attaching a lead wire to each of these divided electrodes can be eliminated, the manufacturing process of the piezoelectric vibration sensor can be reduced, and the piezoelectric vibration sensor can be reduced. It is possible to reduce the cost required for manufacturing.

Since the lead wire can be eliminated, the connection failure due to the disconnection of the lead wire can be eliminated, the spacer for taking out the lead wire between the piezoelectric body and the load body can be eliminated, and the piezoelectric Since the die vibration sensor can be formed thin, the piezoelectric vibration sensor can be downsized.

According to the piezoelectric vibration sensor of the second aspect, since the connecting electrodes are composed of two layers of electrodes, one x-axis connecting electrode of the two layers of electrodes forms a pair of x-axis divided electrodes. Are electrically connected, and the pair of y-axis connecting electrodes are electrically connected by the other y-axis connecting electrode, so that the work of attaching a lead wire or the like to each of these divided electrodes can be omitted.

According to the piezoelectric vibration sensor of the third aspect, since the connecting electrode is composed of the strip electrode and the L-shaped electrode, the strip electrode is for the pair of x axes of the second electrode, or the y axis. One of the divided electrodes for electrical connection is electrically connected, and the other is connected by an L-shaped electrode. Therefore, there is an effect that the work of attaching the lead wire or the like to each divided electrode can be omitted.

[Brief description of drawings]

FIG. 1 is a perspective view showing a piezoelectric vibration sensor of the present invention.

FIG. 2 is a developed perspective view showing a piezoelectric vibration sensor in FIG.

3 is a developed perspective view showing the two-layer laminated electrode of FIG.

FIG. 4 is a developed perspective view showing the three-layer laminated electrode of FIG.

5 is a plan view showing a modified example of FIG.

FIG. 6 is a plan view showing a modified example of FIG.

FIG. 7 is a plan view showing a modification of the second electrode of FIG.

FIG. 8 is a plan view showing a modified example of the middle layer electrode of FIG.

9 is a plan view showing a modified example of the upper layer electrode of FIG.

FIG. 10 is a perspective view showing a conventional piezoelectric vibration sensor.

FIG. 11 is a perspective view showing a conventional piezoelectric body.

FIG. 12 is a circuit diagram showing an output voltage between electrodes of a conventional piezoelectric body.

FIG. 13 is a perspective view showing a conventional piezoelectric vibration sensor.

14 is a plan view showing electrodes arranged on both surfaces of the piezoelectric body of FIG.

[Explanation of reference numerals] 30 ... Piezoelectric vibration sensor, 31 ... Piezoelectric body, 32 ... Substrate,
33 ... Load body, 34 ... Two-layer laminated electrode (multi-layer laminated electrode),
35 ... Three-layer laminated electrode (multilayer laminated electrode), 36 ... First electrode, 37 ... Insulator, 40 ... Second electrode, 40a ... X-axis divided electrode, 40b ... Y-axis divided electrode, 41 ... Middle layer electrode (connection electrode), 42 ... Upper layer electrode (connection electrode), 46
... electric circuit electrodes.

Claims (3)

[Claims] 1. A piezoelectric body, a pair of multi-layer laminated electrodes arranged on both surfaces of the piezoelectric body, and a substrate provided with an electric circuit electrode connected to one of the multi-layer laminated electrodes, And a load body attached to the other of the layer-stacked electrodes. The other multilayer-stacked electrode includes a pair of x-axis split electrodes for detecting displacement of the x-axis in the plane of the piezoelectric body, and a y-axis displacement. A pair of y-axis split electrodes for detection, and a connecting electrode disposed on the x-axis or the y-axis between the load electrode and the x-axis split electrode and the y-axis split electrode. Stacked via an insulating plate, a through hole is formed through the connecting electrode and the insulating plate, and the through hole is formed.
A piezoelectric vibration sensor, characterized in that a connecting portion for electrically connecting the pair of x-axis divided electrodes or the pair of y-axis divided electrodes and the connecting electrode is provided. 2. The piezoelectric vibration sensor according to claim 1, wherein the connecting electrode has two layers of electrodes with an insulating plate interposed therebetween, and one of the two layers of electrodes is provided on the x-axis. Is arranged
X including the intersection of the x-axis and the y-axis at the center of the plane of the piezoelectric body
An axis-connecting electrode is formed, on the other hand, a y-axis connecting electrode that is arranged on the y-axis and includes the intersection is formed, and the x-axis connecting electrode is a pair of second electrodes for the x-axis. The divided electrodes are electrically connected through a connecting portion, and the pair of y-axis divided electrodes of the second electrode is electrically connected through the connecting portion to the y-axis connecting electrode. Characteristic piezoelectric vibration sensor. 3. The piezoelectric vibration sensor according to claim 1, wherein the connecting electrode is arranged on either the x-axis or the y-axis, and the x-axis is at the center of the plane of the piezoelectric body. The strip-shaped electrode includes a strip-shaped electrode including an intersection with the y-axis, and a pair of L-shaped electrodes disposed on the other of the x-axis and the y-axis and spaced apart from the strip-shaped electrode. Is connected to either one of a pair of split electrodes for the x-axis of the second electrode or a split electrode for the y-axis via a connecting portion, and the L-shaped electrode is for the pair of x-axis of the second electrode. , Or the other of the y-axis split electrodes is connected via a connecting portion.