JP2017161246A - Stack type pressure sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stack type pressure sensor with the improved electric connectability between an external electrode member and a side surface electrode portion of a piezoelectric element that are stacked, under the high temperature, the high pressure, and the vibrating environment.SOLUTION: A stack type pressure sensor 10 includes: a piezoelectric element stack 1 including a plurality of piezoelectric elements 11 that are stacked, and a side surface electrode portion 15 provided at a side surface of each piezoelectric element 11; a conductive member 2 that is electrically connected to the side surface electrode portion 15; and an external electrode member 3 that is electrically connected to the conductive member 2. The conductive member 2 is configured to have a pressing portion 21 that presses each side surface electrode portion 15 with the force toward the side surface electrode portion 15. A pitch P1 of the pressing portion 21 is preferably less than or equal to a pitch P2 of the side surface electrode portion 15 arranged in a stacking direction Y of the piezoelectric element stack 1. The conductive member 2 is preferably a coil spring 22.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a laminated pressure sensor, and more specifically, a laminated type in which electrical connectivity between a side electrode portion of a laminated piezoelectric element and an external electrode member is improved under a high temperature, high pressure and vibration environment. The present invention relates to a pressure sensor.

  A pressure sensor including a piezoelectric element is known as a sensor for detecting pressure under a high temperature, high pressure, and vibration environment such as an internal combustion engine such as a gas turbine or an engine. In particular, when measuring a dynamic pressure phenomenon such as a pulsating pressure, a stacked pressure sensor capable of measuring with high accuracy is used. A laminated pressure sensor is a laminate of flat piezoelectric elements. Each piezoelectric element is provided with a side electrode, and the side electrode is electrically connected to an external electrode. ing.

  As such a laminated pressure sensor, Patent Document 1 proposes a piezoelectric element for an injector that consumes less energy, can respond at high speed, and has improved bonding between an external electrode and a side electrode. In this piezoelectric element, an external electrode that is electrically connected to the outside is disposed on the side electrode of the piezoelectric element, and the external electrode includes a core material and a metal coating that covers at least a part thereof. In addition, it is joined to at least the side electrode. According to this technology, it is possible to give flexibility to the external electrode from the shape surface, and it is possible to relieve the stress at the time of expansion of the piezoelectric element, so it is possible to suppress the occurrence of cracks, etc. By filling the conductive adhesive without any gap, the bonding between the external electrode and the side electrode can be ensured.

  Further, in Patent Document 2, stress is generated between the side electrode of the multilayer piezoelectric element in which the entire multilayer body expands and contracts and the external electrode that does not expand and contract, and the external electrode is peeled off or broken due to the stress. There has been proposed a piezoelectric element for an injector which is less likely to cause the above-described problem and has excellent durability even when used for a long period of time. In this piezoelectric element, a plurality of piezoelectric elements and a plurality of internal electrodes are alternately stacked on two or more side surfaces of a prismatic laminated body, and a plurality of end portions of the internal electrodes are insulated from each other. An insulating coating layer and an external electrode for electrically connecting in parallel the end portions of the internal electrode that are not insulated by the insulating coating layer are formed. The external electrode is in contact with the first external electrode layer formed on the side surface of the prismatic laminate including the insulating coating layer, and at least two places in contact with the first external electrode layer. It is composed of an external electrode layer and a plurality of conductive bonding materials for bonding the first external electrode layer and the second external electrode layer, and the first external electrode layer includes at least two layers It is characterized in that it is formed so as to integrally cover the side surface of the piezoelectric layer.

Japanese Patent Laid-Open No. 2002-202024 JP 2005-183478 A

  The stacked pressure sensor proposed in Patent Documents 1 and 2 improves the bonding structure and bonding member between the side electrode and the external electrode to prevent problems such as peeling and destruction of the external electrode.

  However, when the side electrode and the external electrode are bonded, there is a possibility that the bonded portion may be broken or peeled off due to a load applied in a measurement environment of a dynamic pressure phenomenon. Further, even when an external electrode having a shape capable of absorbing the expansion and contraction of the laminate is bonded to the side electrode, the bonded portion may be broken or peeled off by a load applied in a measurement environment.

  In the laminated pressure sensor, a piezoelectric element having a certain size is used, but the side surface of the laminated body after the piezoelectric element is laminated is not necessarily flat, and the side electrodes may be uneven. The bonding of the external electrode to the side electrode that causes the unevenness needs to be performed in consideration of the degree of the unevenness, and there is a problem that the bonding is difficult and the bonding strength is not stable.

  The present invention has been made in order to solve the above-described problems. The object of the present invention is to provide an electrical connection between a side electrode portion of a laminated piezoelectric element and an external electrode member in a high temperature, high pressure and vibration environment. An object of the present invention is to provide a stacked pressure sensor with improved connectivity.

  The laminated pressure sensor according to the present invention includes a piezoelectric element laminate having a plurality of laminated piezoelectric elements and side electrode portions provided on the side surfaces of the piezoelectric elements, and a conductive element electrically connected to the side electrode portions. A laminated pressure sensor having a member and an external electrode member electrically connected to the conductive member, wherein the conductive member has a pressing portion that presses each side electrode portion with a force toward the side electrode portion. It is characterized by. Note that the force toward the side electrode portion can also be referred to as “biasing force” or “pressing force”.

  According to the present invention, the conductive member electrically connected to the side electrode portion of the piezoelectric element laminate is provided with a conductive member having a pressing portion that presses each side electrode portion with a force toward the side electrode portion. Therefore, since the conductive member in the present invention presses the side electrode portions one by one, high temperature and vibration are applied to the pressure sensor under high temperature, high pressure and vibration environment, and the piezoelectric element laminate itself expands and contracts. Even if the side surface of the piezoelectric element laminate is uneven, the pressing force to each side electrode portion does not change. As a result, the contact between the side electrode portion and the conductive member is stabilized, so that the electrical connectivity can be improved. In addition, since the electrically-conductive member in this invention is not joined to the side electrode part with solder, a conductive paste, or the like, there is no possibility of causing breakage or peeling at the joint part as in the prior art.

  In the stacked pressure sensor according to the present invention, the pitch of the pressing portions is equal to or less than the pitch of the side electrode portions arranged in the stacking direction of the piezoelectric element stack.

  According to this invention, since the pitch of the pressing portions is equal to or less than the pitch of the side electrode portions arranged in the stacking direction of the piezoelectric element laminate, there is always a pressing portion corresponding to each side electrode portion. Thus, the contact between the side electrode portion and the conductive member is reliably performed, and the electrical connectivity can be improved. In addition, it is preferable that the pitch of a side electrode part is a pitch of a side electrode part when a piezoelectric element laminated body contracts to the maximum, and a contact between a side electrode part and a conductive member can be performed more reliably.

  In the stacked pressure sensor according to the present invention, the conductive member is preferably a coil spring.

  According to the present invention, since the coil spring is used, the surface of each wire on the outer periphery of the coil spring wound in a coil shape has a biasing force in a direction orthogonal to the central axis direction of the coil spring. As a result, the surface of each wire on the outer periphery of the coil spring becomes a pressing portion that presses each side electrode portion with a force toward the side electrode portion, and can press each side electrode portion. In addition, there exist a tension coil spring, a compression coil spring, a close-contact coil spring, etc. in a coil spring, The pitch can be match | combined and can be used.

  The laminated pressure sensor according to the present invention preferably includes a biasing member that biases the conductive member toward the side electrode portion.

  According to this invention, since the urging member that urges the conductive member toward the side electrode portion is provided, the pressing portion of the conductive member can be pressed to each side electrode portion in a more stable state.

  In the multilayer pressure sensor according to the present invention, it is preferable that the biasing member is a guide member that positions the piezoelectric element multilayer body together with the conductive member.

  According to the present invention, the biasing member for biasing the conductive member toward the side electrode portion functions as a guide member for positioning the piezoelectric element laminate together with the conductive member. The conductive member can be pressed against the side electrode part in the positioned state. As a result, the contact between the pressing portion of the conductive member and each side electrode portion becomes more reliable.

  In the stacked pressure sensor according to the present invention, the biasing member includes a guide member that directs the conductive member toward the side electrode portion, and a spring member that biases the guide member toward the side electrode portion. Can be configured.

  Although the structural form of the biasing member can be designed in various ways, according to the present invention, the biasing member has a guide member that directs the conductive member toward the side electrode part and a spring member that biases the guide member toward the side electrode part. With a simple combination of the guide member and the spring member, the guide member can be biased to the side electrode portion side after guiding the conductive member and the piezoelectric element laminate.

  According to the present invention, it is possible to provide a stacked pressure sensor in which electrical connectivity between the side electrode portions of the stacked piezoelectric elements and the external electrode member is improved in a high temperature, high pressure and vibration environment. .

  In particular, since the conductive member in the present invention presses the side electrode portions one by one, high temperature and vibration are applied to the pressure sensor under high temperature, high pressure and vibration environment, and the piezoelectric element laminate itself expands and contracts. Even if the side surface of the piezoelectric element laminate is uneven, the pressure on each side electrode portion does not change. As a result, the contact between the side electrode portion and the conductive member is stabilized, so that the electrical connectivity can be improved. Since the conductive member in this invention is not joined to the side electrode part with solder, conductive paste, or the like, there is no possibility of causing breakage or peeling at the joint part as in the prior art.

It is a section lineblock diagram showing an example of a lamination type pressure sensor concerning the present invention. It is a disassembled perspective view for demonstrating the structural member of the lamination type pressure sensor shown in FIG. It is explanatory drawing of the piezoelectric element which comprises a piezoelectric element laminated body. It is explanatory drawing of the side electrode part of a piezoelectric element laminated body. It is explanatory drawing which shows the positional relationship of each side electrode part of a piezoelectric element laminated body, and a conductive member. It is an example of a coil spring. It is a perspective view when a large sized coil spring is used as an urging member. It is a section lineblock diagram showing an example of a lamination type pressure sensor when a washer is used as a biasing member. It is a cross-sectional block diagram which shows another example of a laminated pressure sensor when a large sized coil spring is used as an urging member.

  A laminated pressure sensor according to the present invention will be described with reference to the drawings. The laminated pressure sensor according to the present invention is not limited to the following embodiments and drawings, and various modifications are possible within the scope of the gist of the present invention.

[Laminated pressure sensor]
As shown in FIG. 1, a stacked pressure sensor 10 according to the present invention includes a plurality of stacked piezoelectric elements 11 and a piezoelectric element stack 1 having side electrode portions 15 provided on the side surfaces of the piezoelectric elements 11. The conductive member 2 is electrically connected to the side electrode portion 15 and the external electrode member 3 is electrically connected to the conductive member 2. The conductive member 2 includes a pressing portion 21 that presses each side electrode portion 15 with a force F <b> 1 directed toward the side electrode portion 15. Note that the force toward the side electrode portion can also be referred to as “biasing force” or “pressing force”.

  The stacked pressure sensor 10 is used by being attached to a pressure measurement object as a sensor for detecting pressure under a high temperature, high pressure and vibration environment such as an internal combustion engine such as a gas turbine or an engine. Since the conductive member 2 constituting the laminated pressure sensor 10 presses the side surface electrode portions 15 one by one, high temperature and vibration are applied to the pressure sensor under high temperature, high pressure and vibration environment. Even if the body itself expands and contracts, and even if the side surface of the piezoelectric element laminate 1 is uneven, the pressing force F1 to each side electrode portion 15 does not change. As a result, since the contact between the side electrode part 15 and the conductive member 2 is stabilized, the electrical connectivity can be improved. Since the conductive member 2 is not joined to the side electrode part 15 with solder, conductive paste, or the like, there is no possibility that breakage or peeling will occur at the joint part as in the prior art.

  Hereinafter, the components of the stacked pressure sensor will be specifically described.

<Piezoelectric element laminate>
As shown in FIGS. 1 to 4, the piezoelectric element laminate 1 is laminated with a plurality of piezoelectric elements 11. The piezoelectric element laminate 1 is a sensor member that detects a pressure by using a piezoelectric action, and the piezoelectric element laminate 1 generates electric charges when the pressure of the measurement object applied to the diaphragm head 56 fluctuates. The electric charge is detected through the side electrode part 15, the external electrode member 3 and the electrode pin 6. The piezoelectric element laminate 1 can efficiently collect charges generated by the laminated piezoelectric elements 11 and increase the sensitivity of the sensor. In addition, since the piezoelectric element laminate 1 has an integrated block shape, even if the strength of the individual piezoelectric elements 11 is insufficient, the piezoelectric element laminate 1 should be used in a severe operating environment such as high temperature, high pressure, and vibration environment. Can do.

  As shown in FIGS. 1 to 4, the piezoelectric element laminate 1 has a quadrangular rectangular column shape in plan view because the piezoelectric element 11 having a rectangular shape and a thin plate shape are laminated. The shape in plan view is preferably a quadrangle, but may be a polygon other than a quadrangle, a square having a curved portion, or a curved shape not including a corner. Although the magnitude | size of the piezoelectric element laminated body 1 is not specifically limited, For example, as an example in the case of using it for the measurement with a gas turbine, it can be set as thickness about 0.5 mm, about 5 mm long, and about 3 mm wide.

(Piezoelectric element)
The piezoelectric element 11 is an element constituting the piezoelectric element laminate 1, and is preferably a thin plate shape such as a quadrangle, but is not particularly limited to that shape. The constituent material of the piezoelectric element 11 may be selected depending on its application, and the piezoelectric element 11 that detects pressure under high temperature, high pressure, and vibration environment is preferably an element made of a langate crystal. When Langatate crystals are used, Langatate crystals (Langatate (La3Ga5.5Ta0.5O14 / LGT) crystals) have no pyroelectricity and no Curie point. For example, they can be used at high temperatures of 600 ° C or higher. It is possible to maintain stable piezoelectric characteristics over a wide temperature range. As the piezoelectric element 10 other than the langate crystal, depending on the use environment, langasite, gehlenite, gallium phosphate, crystal, lead zirconate titanate, lithium niobate, tourmaline, lithium tantalum oxide, lithium tantalate The piezoelectric element which consists of etc. can be mentioned.

(electrode)
As shown in FIGS. 3 and 4, the piezoelectric element 11 has an upper surface electrode 13 on the upper surface and a lower surface electrode 14 on the lower surface. The upper electrode 13 and the lower electrode 14 are electrically connected to side electrodes 12 (12a, 12b) provided on different end surfaces. For example, as shown in FIG. 3, an electrode film having a predetermined thickness is continuously provided as the upper surface electrode 13 and the left side electrode 12a, and electrically connects the upper surface electrode 13 and the left side electrode 12a. . Similarly, an electrode film having a predetermined thickness is provided continuously as the lower electrode 14 and the right side electrode 12b, and electrically connects the lower electrode 14 and the right side electrode 12b. Since the upper electrode 13 and the lower electrode 14 are not connected, the upper electrode 13 is electrically connected only to one side electrode 12a, and the lower electrode 14 is electrically connected only to the other side electrode 12b.

  The side electrodes 12 are provided on the two side surfaces of the piezoelectric element 11. When the piezoelectric element 11 is square, as shown in FIGS. 3 and 4, the side electrodes 12 are provided on two opposite sides. In addition, as long as it is two sides of a rectangle, it does not need to be two opposite sides, and may be two adjacent sides.

  In the piezoelectric element laminate 1, such piezoelectric elements 10 are alternately laminated. In the laminated form, a side electrode portion 15 is provided in which only one end face of two piezoelectric elements adjacent in the lamination direction is common. Specifically, as shown in FIG. 4, the lowermost piezoelectric element and the upper piezoelectric element are connected to the upper surface electrode 13 so that the left side electrode is connected to form the side electrode portion 15. The lower surface electrode 14 is laminated in surface connection, and the second piezoelectric element from the bottom is stacked on the upper surface so that the right side electrode is connected to form the side electrode part 15. The electrode 13 and the lower electrode 14 are laminated in a surface connection. The piezoelectric elements 10 are sequentially stacked in such a form. As shown in FIG. 4, the non-side electrode part 16 is a part that is not the side electrode part 15, and the side electrode parts 15 and the non-side electrode parts 16 are provided so as to alternately exist in the stacking direction. Yes.

  The side electrode 12, the upper surface electrode 13, and the lower surface electrode 14 are configured by electrode films. The electrode film is composed of a highly conductive conductive layer and an adhesive layer that is provided between the piezoelectric element and the conductive layer and improves the adhesion between them. The constituent material of the electrode film is not particularly limited. For example, the conductive layer can be selected from Au, Pd, Pt, Ag, Cu, and alloys thereof, and the adhesion layer can be Ti, Pt, TiW, Co. , Ni, Cr and alloys thereof can be selected. Each electrode film may be formed by forming an electrode film material on the piezoelectric element and then patterning by photolithography. Alternatively, each electrode film may be formed by sputtering or sputtering after placing a metal mask having an electrode film forming portion on the piezoelectric element. It may be formed by vapor deposition. Although the thickness of an electrode film is not specifically limited, For example, it can be in the range of 300 nm or more and 500 nm or less.

(Positioning)
The piezoelectric element laminate 1 thus configured is positioned and installed between the upper plate 51 and the lower plate 52 that constitute the laminated pressure sensor 10 as shown in FIGS. 1 and 2. As shown in FIGS. 2 and 7, the positioning is performed by positioning pins 71 and 71 arranged on two sides where the side electrode portion 15 is not provided. However, the positioning is not necessarily limited to such positioning means. Note that the two sides where the side electrode part 15 is not provided are the two opposite sides in FIGS. 2 and 7, but may be adjacent two sides depending on the position of the side electrode part 15.

  In the example of FIG. 2, the positioning pins 71 are attached to the lower plate 52 in a state where the pair of positioning pins 71, 71 face each other (facing each other). Between the opposing positioning pins 71, 71, the piezoelectric element laminate 1 is inserted and positioned. The positioning pin 71 is finally inserted into a positioning pin guide hole 72 provided in the upper plate 51 and fixed so as not to move.

  In the laminated pressure sensor 10, a diaphragm head 56 is provided at the front end portion of the main body cover 55. The diaphragm head 56 is attached and sealed to the main body cover 55 by means such as welding. The pressure applied from the diaphragm head 56 located at the tip of the stacked pressure sensor 10 is applied to the piezoelectric element stacked body 1 through the upper plate 51 from the lower surface side of the diaphragm head 56. With such a structure, charges are generated in the piezoelectric element laminate 1 due to fluctuations in the pressure of the measurement object applied to the diaphragm head 56, and the charges pass through the side electrode portion 15, the external electrode member 3 and the electrode pin 6. Configured to detect.

<Conductive member>
As shown in FIGS. 1, 2, and 5, the conductive member 2 is provided so as to be in contact with and electrically connected to the side electrode portions 15 located on two opposite sides of the piezoelectric element laminate 1. . The “contact” means that it is not joined with a conventional solder or conductive paste. In the example of FIG. 1 and FIG. 2, it is provided on two opposite sides. However, as described in the description section of the electrode described above, the two sides are not necessarily opposite if they are two sides. “Electrically connected” means that an electrical connection state between the side electrode portion 15 and the conductive member 2 is secured by contact between the side electrode portion 15 and the conductive member 2.

  The conductive member 2 has a pressing portion 21 that presses each side electrode portion 15 with a force F1 (also referred to as urging force or pressing force, hereinafter referred to as “biasing force F1”) toward the side electrode portion 15. Specifically, a member having springiness is used. Among them, a spring material, particularly a coil spring as shown in FIG. 6, is preferably used, but is not necessarily limited to a spring material such as a coil spring.

  That is, in the present invention, as shown in FIG. 5, when the conductive member 2 contacts the side electrode portion 15, the conductive member 2 must have a biasing force F <b> 1 directed toward the side electrode portion 15. is there. The conductive member 2 provided with such an urging force F1 may be a member having a spring property. Due to the spring property of such a member, when the conductive member 2 comes into contact with the side electrode portion 15, the conductive member 2 comes into contact with the urging force F1. Become. As a result, electrical connection between the conductive member 2 and the side electrode portion 15 is ensured.

  The conductive member 2 ensures electrical connection with the side electrode portion 15 and electrical connection with the external electrode member 3. Therefore, it is preferable that the material has good conductivity and low contact resistance. As a material of such a conductive member 2, for example, Cu, Fe, Ni or an alloy thereof is preferable. Furthermore, the surface is preferably plated with a corrosion-resistant and highly conductive metal such as Au. Further, when used in a high temperature environment such as a gas turbine, a heat-resistant Ni alloy is preferable, and examples include Inconel (registered trademark) and Hastelloy (registered trademark).

  The positional relationship between the conductive member 2 and the side electrode part 15 corresponds to the position of the conductive member 2 and the position of the side electrode part 15 as shown in FIG. More preferably, considering that the piezoelectric element laminate 1 is compressed by the pressure applied to the laminated pressure sensor 10, the pitch P1 of the pressing portions 21 of the conductive member 2 is determined depending on the degree of compression. It is preferable that the pitch is equal to or less than the pitch P2 of the side surface electrode portions 15 arranged in the stacking direction Y of the stacked body 1. By adopting such a pitch, each side electrode portion 15 is in a positional relationship in which the corresponding pressing portion 21 is necessarily present, and the contact between the side electrode portion 15 and the conductive member 2 is ensured, and electrical Connectivity can be improved. The pitch P2 of the side electrode parts 15 is preferably the pitch of the side electrode parts 15 when the piezoelectric element laminate 1 is maximally contracted, and the contact between the side electrode parts 15 and the conductive member 2 is more reliable. Can be done.

  As the coil spring 22, as shown in FIG. 6, a compression coil spring 23, a tension coil spring 24, a contact coil spring (not shown), and the like can be given. The coil spring used here is not a general spring that requires only springiness, but must have electrical conductivity at the same time. Therefore, when selecting the coil spring 22, the electric conductivity, the pitch P1, the coil outer diameter, the wire diameter, the free height, etc. are taken into consideration, and further, the coil spring 22 is attached to the side electrode portion 15 in the direction X perpendicular to the central axis direction. It is desirable to select in consideration of the magnitude of the force F1. In such a coil spring 22, the surface 22 a of each line on the outer periphery of the coil spring wound in a coil shape is provided with a biasing force F <b> 1 in the direction X orthogonal to the central axis direction of the coil spring 22. The surface 22 a of each line serves as a pressing portion 21 that presses each side electrode portion 15 and presses each side electrode portion 15.

  As an example, when the length in the stacking direction Y of the piezoelectric element laminate 1 is 1.2 mm and the pitch P2 of the side electrode portions 15 is about 0.2 mm, a wire having an outer diameter of 3.1 mm made of, for example, a Ni alloy is used. A compression coil spring having a coil wire diameter of 0.2 mm and a pitch P1 of 0.2 mm can be used.

<External electrode member>
The external electrode member 3 is a member that is electrically connected to the conductive member 2. If it is the external electrode member 3 which has such a function, the structure form will not be specifically limited, For example, as shown in FIG.1 and FIG.2, the pin inserted in the electrically-conductive member 2 which consists of a coil spring 22 is shown. It is preferable that the external electrode member 3 is in the shape of a ring. In the example of FIGS. 1 and 2, the external electrode member 3 is attached so as to penetrate the lower plate 52, and finally inserted into the guide hole 32 provided in the upper plate 51 and fixed so as not to move. Is done. The upper plate 51 with which the external electrode member 3 may come into contact is preferably insulative, or the guide hole 32 portion and its inner peripheral surface are insulated.

  The material of the external electrode member 3 is not particularly limited as long as it has good conductivity. For example, it may be made of a material such as Au, Pd, Pt, Ag, Cu, Ni, Fe, or an alloy thereof. preferable. The surface of the external electrode member 3 may be provided with a plating film for improving wear resistance, corrosion resistance, and conductivity. Further, the size of the external electrode member 3 is not particularly limited as long as it corresponds to the shape and dimensions of the conductive member 2. For example, when the conductive member 2 is a coil spring 22, the inner diameter of the coil spring 2 is larger. It is preferable that the wire has a small diameter.

  One end side of the external electrode member 3 is electrically connected to the conductive member 2, and the other end side is electrically connected to the electrode pin 6. The other parts are insulated. For example, it is insulated from other members such as the inner body 53 by an insulating electrode pin guide 61 such as an insulating pipe. At this time, when the inner body 53, the lower plate 52, and the other component members that may come into contact with the external electrode member 3 are insulative, the electrode pin guide 61 does not necessarily need to be insulative. Preferably it is insulating. As the electrode pin guide 61 made of an insulating pipe, an alumina ceramic pipe can be preferably used, and a resin pipe may be used when heat resistance is not required.

  The external electrode member 3 is connected to the electrode pin 6 shown in FIG. The external electrode member 3 and the electrode pin 6 may be separate members, or may be the same one made of a single body. If they are separate, they may be joined by soldering or caulking.

  In the example of FIG. 2, the electrode pin 6 to which the external electrode member 3 contacts is drawn out to the opposite side of the diaphragm head 56 through the inside of the inner body 53. The laminated pressure sensor 10 is configured such that the electrode pin 6 is connected to a receptacle (not shown) as a connecting member, and a charge signal output from the electrode pin 6 is detected via the receptacle. Is done.

<Biasing member>
The urging member 4 is a member that urges the conductive member 2 toward the side electrode portion 15 as shown in FIGS. 1, 2, and 7. In order for the conductive member 2 having a spring property to contact the side electrode portion 15 with a predetermined biasing force F1, the conductive member 2 having a spring property is moved from the outer peripheral side (that is, the side opposite to the side electrode portion 15). While pressing to some extent, it is necessary to function as a guide member that positions and fixes the position. The urging member 4 has such a function, and the structure form is not particularly limited as long as it has the function.

  As the urging member 4, various structural forms can be used as long as they have the functions and roles described above. As an example of the urging member 4, as shown in FIGS. 1 and 2, a split type that functions to fix the position of the two conductive members 2 that are electrically connected to the opposing end surfaces of the piezoelectric element laminate 1. A combination member of the guide member 41 and the spring member 42 that functions to be pressed from both sides can be exemplified. Since the urging member 4 made of such a combination member can urge the conductive member 2 having a spring property toward the side electrode portion 15, the pressing portion 21 included in the conductive member 2 is more stable in each state. The side electrode portion 15 can be pressed. As a result, the contact between the pressing portion 21 of the conductive member 2 and each side electrode portion 15 becomes more reliable.

  The biasing member 4 in which the guide member 41 and the spring member 42 are combined can be exemplified by the forms shown in FIGS. 1, 2, and 7. The guide member 41 includes a conductive member accommodating portion 43 that accommodates the conductive member 2, a spring member abutting portion 44 that abuts the spring member 42 pushed down from above, and a positioning pin accommodating portion 45 that accommodates the positioning pin 71. It is a split mold member. As in the mounting examples shown in FIGS. 2 and 7, the split mold member is disposed so as to sandwich the piezoelectric element laminate 1 from both ends. Such a biasing member 4 can exhibit the function and role of the biasing member 4 described above.

  As the spring member 42, as shown in FIGS. 2 and 7, a large spring that acts so as to apply a compressive force from the outer periphery to the inner side with the split-type guide member 41 attached can be preferably cited. it can. For such a large coil spring, the wire diameter and material are selected in consideration of the compressive force applied inward. Further, since the large coil spring is mounted so as to be fitted into the split member from above, it is mounted by being pushed down from above until the large spring comes into contact with the contact portion 44.

  FIG. 8 shows another form of the urging member, in which the spring member 42 is changed to a disc spring 46 and a washer 47 instead of a large coil spring. The washer 47 has a function of restraining the split member 4 from the outer periphery, and the disc spring 46 has a function of pressing the washer 47 downward. The function and role of the urging member 4 can also be exhibited by the urging member 4 in such a combination.

(Other configurations)
FIG. 9 shows an example in which the form of the upper plate 51 is changed. In this example, the size of the upper plate 51 is reduced to reduce the weight, and the reduced upper plate 51 is arranged inside a spring member 42 made of a large coil spring. Accordingly, the large coil spring is pressed from above by the diaphragm head 56. Other than that, it is the same as the structure shown in FIG. In this example, since the upper plate 51 can be made small and light in weight, the pressure exerted on the diaphragm head 56 when the acceleration is applied to the pressure sensor can be reduced, and the diaphragm head 56 can be damaged or fatigued. Destruction can be suppressed.

  As described above, according to the laminated pressure sensor 10 of the present invention, the electrical connection between the side electrode portion 15 of the laminated piezoelectric element 11 and the external electrode member 3 is performed under high temperature, high pressure, and vibration environment. The stacked pressure sensor 10 with improved connectivity can be provided.

  In particular, since the conductive member 2 in the present invention presses the side electrode portions one by one, high temperature and vibration are applied to the pressure sensor under high temperature, high pressure and vibration environment, and the piezoelectric element laminate itself expands and contracts. Even if it occurs, even if the side surface of the piezoelectric element laminate 1 is uneven, the pressure on each side electrode portion 15 does not change. As a result, since the contact between the side electrode part 15 and the conductive member 2 is stabilized, the electrical connectivity can be improved. Since the conductive member 2 in the present invention is not joined to the side electrode portion 15 with solder, conductive paste or the like, there is no possibility of causing breakage or peeling at the joint portion as in the prior art.

DESCRIPTION OF SYMBOLS 1 Piezoelectric element laminated body 2 Conductive member 3 External electrode member 4 Energizing member (split type member)
6 Electrode Pin 10 Multilayer Pressure Sensor 11 Piezoelectric Element 12, 12a, 12b Side Electrode 13 Top Electrode 14 Bottom Electrode 15 Side Electrode Part 16 Side Non-electrode Part 21 Pressing Part 22 Coil Spring 22a Wire Surface 23 Compression Coil Spring 24 Tension Coil Spring 32 Guide hole of external electrode member 41 Guide member 42 Spring member 43 Conductive member accommodating portion 44 Spring member abutting portion 45 Positioning pin accommodating portion 46 Belleville spring 47 Washer 51 Upper plate 52 Lower plate 53 Inner body 54 Cover plate 55 Body cover 56 Diaphragm head 57 Load section 61 Electrode pin guide 71 Positioning pin 72 Positioning pin guide hole Y Stacking direction X Direction perpendicular to the central axis direction of the spring F1 Force toward the side electrode section (biasing force or pressing force)
P1 Pitch of pressing part P2 Pitch of side electrode part

Claims (6)

A plurality of stacked piezoelectric elements and a piezoelectric element laminate having a side electrode portion provided on each side surface of the piezoelectric element, a conductive member electrically connected to the side electrode portion, and electrically connected to the conductive member A laminated pressure sensor having an external electrode member to be connected;
The conductive pressure member includes a pressing portion that presses each side electrode portion with a force directed toward the side electrode portion.   2. The stacked pressure sensor according to claim 1, wherein a pitch of the pressing portions is equal to or less than a pitch of the side electrode portions arranged in a stacking direction of the piezoelectric element stack.   The stacked pressure sensor according to claim 1, wherein the conductive member is a coil spring.   The stacked pressure sensor according to claim 1, further comprising an urging member that urges the conductive member toward the side electrode portion.   The laminated pressure sensor according to claim 1, wherein the biasing member is a guide member that positions the piezoelectric element laminate together with the conductive member.   The said urging member has a guide member which orient | assigns the said electrically-conductive member to the said side electrode part side, and a spring member which urges | biases this guide member to the said side electrode part side. The laminated pressure sensor according to 1.

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