JP6798874B2 - Pressure detector - Google Patents

Description

The present invention relates to a pressure detection device that detects pressure.

Patent Document 1 describes a combustion pressure sensor in which three or more sensor elements, each of which measures a combustion pressure in a cylinder, are arranged in a ring shape.
Further, in Patent Document 2, in a pressure detection device that detects pressure using a piezoelectric element, the piezoelectric element is defined in advance by sandwiching the piezoelectric element from the front and back in the direction in which pressure is applied by using two members. It is stated that a load (preload) is applied.

JP-A-2015-190333 Japanese Unexamined Patent Publication No. 2013-1745553

In the pressure detection device, the conductive member and others are used for the purpose of insulating the conductive member that constitutes the electrical path for transmitting the output from the piezoelectric element from the other conductive member that constitutes another electrical path. An insulating member having an insulating property may be interposed between the conductive member and the conductive member. When a configuration is adopted in which a plurality of piezoelectric elements are arranged side by side and a conductive member, an insulating member, and other conductive members are arranged along the direction in which a preload is applied to each piezoelectric element, the piezoelectric element faces the piezoelectric element. There is unevenness in the distribution of the force applied to the insulating member between the parts that do and the parts that do not face each other. As a result, cracks may occur in the insulating member to which the preload is applied. At this time, since there is no regularity in the portion where the insulating member cracks, for example, when the insulating member cracks in the portion facing the piezoelectric element, the preload applied to the piezoelectric element may fluctuate. there were.

An object of the present invention is to suppress fluctuations in preload applied to a plurality of piezoelectric elements due to cracking of an insulating member in a pressure detection device including a plurality of piezoelectric elements.

The pressure detection device of the present invention has a plurality of piezoelectric elements for detecting a change in pressure from one end side to the other end side using a piezoelectric body, and one end side of each of the plurality of piezoelectric elements having conductivity. The electrode member that comes into contact with the electrode member, the support member that supports the plurality of piezoelectric elements via the electrode member, and the plurality of piezoelectric elements that have insulating properties and are arranged between the electrode member and the support member. The parts that do not face each other include an insulating member provided with a fragile part that is fragile as compared with the parts that face each other.
In such a pressure detecting device, the fragile portion provided in the non-opposing portion of the insulating member is characterized in that the thickness in the direction from one end side to the other end side is thinner than the facing portion. Can be.
Further, the fragile portion can be characterized by being a recess provided on the surface on the other end side of the insulating member.
Further, the fragile portion can be characterized by having cracks.
Further, another electrode member having conductivity and in contact with the other end side of each of the plurality of piezoelectric elements, and a portion arranged on the other end side of the other electrode member and not facing the plurality of piezoelectric elements. Is arranged on the other end side of the other insulating member and another insulating member provided with another fragile portion that is fragile as compared with the opposite portion, and the electrode member is provided between the support member and the plurality of electrode members. The piezoelectric element, the other electrode member, and the sandwiching member that sandwiches the other insulating member can be further included.
Further, among the other insulating members, the other fragile portion provided at the non-opposing portion is characterized in that the thickness in the direction from one end side to the other end side is thinner than the facing portion. be able to.
Further, the other fragile portion can be characterized by being a recess provided on a surface on one end side of the other insulating member.
Then, it can be characterized that the other fragile portion has a crack.

According to the present invention, in a pressure detecting device including a plurality of piezoelectric elements, it is possible to suppress fluctuations in the preload applied to the plurality of piezoelectric elements due to cracking of the insulating member.

It is a perspective view which shows the whole structure of the pressure detection apparatus to which this embodiment is applied. FIG. 2 is a sectional view taken along line II-II of FIG. (A) is a partial cross-sectional view of the tip side of the pressure detection device, and (b) is a cross-sectional view of IIIB-IIIB of (a). (A) to (c) are diagrams for explaining the structure of the pedestal member. (A) is a perspective view of the rear end side insulating plate, and (b) is a perspective view of the front end side insulating plate. (A) is a perspective view of the rear end side electrode plate, and (b) is a perspective view of the front end side electrode plate. (A) is a perspective view of the first piezoelectric element, and (b) is a sectional view taken along line VIIB-VIIB of (a). It is a perspective view of the pressure applying member. (A) is a diagram for explaining the positional relationship between the rear end side insulating plate and the first piezoelectric element to the third piezoelectric element, and (b) is a diagram for explaining the front end side insulating plate and the first piezoelectric element to the third piezoelectric element. It is a figure for demonstrating the positional relationship with. It is a flowchart which shows the manufacturing procedure of the detection part which constitutes a pressure detection apparatus. (A) is a diagram for explaining a laser welding process, and (b) is a diagram for explaining a laser irradiation process. It is an SEM photograph which shows the state of the outer peripheral surface of the tip side electrode plate, the tip side insulation plate and the pressure applying member after a laser irradiation step.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[Configuration of pressure detector]
FIG. 1 is a perspective view showing the overall configuration of the pressure detecting device 20 to which the present embodiment is applied. 2 is a sectional view taken along line II-II of FIG. Further, FIG. 3A is a partial cross-sectional view on the tip end side of the pressure detection device 20, and FIG. 3B is a cross-sectional view taken along the line IIIB-IIIB of FIG. 3A.
The pressure detecting device 20 is attached, for example, in the vicinity of a combustor of a gas turbine engine (not shown), and detects (measures) the combustion pressure generated in the combustor.

The pressure detection device 20 has a detection unit 30 for detecting the pressure received from a detection target such as a combustor, and a housing unit 40 for accommodating a main part of the detection unit 30 inside. Further, the pressure detection device 20 is attached to one end side of the housing portion 40, receives the pressure from the detection target, and transmits the received pressure to the detection unit 30, and the other end side of the housing portion 40. It has an output unit 60 which is attached to and outputs a detection signal of the detection unit 30 to an externally provided device (control device or analysis device: not shown). In the pressure detection device 20, the engine housing of the gas turbine engine is such that the transmission unit 50 side is exposed inside the gas turbine engine and faces the combustor, and the output unit 60 side is exposed to the outside of the gas turbine engine. It is attached and fixed through. Therefore, in the following description, the transmission unit 50 side (one end side) of the pressure detection device 20 will be referred to as the "tip side", and the output unit 60 side (the other end side) will be referred to as the "rear end side". Further, in the following description, the direction of the center line of the pressure detecting device 20 shown by the alternate long and short dash line in FIG. 1 is simply referred to as “center line direction”.

Then, each part constituting the pressure detection device 20 will be described.
[Configuration of detector]
The detection unit 30 includes a pedestal member 31 located on the rearmost end side, a rear end side insulating plate 32 arranged on the front end side of the pedestal member 31, and a rear end arranged on the front end side of the rear end side insulating plate 32. It includes a side electrode plate 33. Further, the detection unit 30 has three piezoelectric elements arranged on the front end side of the rear end side electrode plate 33 (first piezoelectric element 341, second piezoelectric element 342, and third piezoelectric element 343: an example of a plurality of piezoelectric elements). The piezoelectric element group 34 including the above is included. Further, the detection unit 30 includes a tip side electrode plate 35 arranged on the tip side of the piezoelectric element group 34, a tip side insulating plate 36 arranged on the tip side of the tip side electrode plate 35, and a tip side insulating plate 36. It is provided with a pressure applying member 37 that is arranged on the tip side and is integrated with the pedestal member 31 by being joined to the pedestal member 31 by laser welding. Furthermore, the detection unit 30 has a rear end side electrode pin 38 whose front end side is connected to the rear end side electrode plate 33 and whose rear end side projects toward the rear end side from the pedestal member 31, and a front end side electrode plate 35. The front end side electrode pin 39 is provided so as to be connected to the pedestal member 31 and to project toward the rear end side from the pedestal member 31.

Subsequently, each member constituting the detection unit 30 will be described.
(Pedestal member)
FIG. 4 is a diagram for explaining the configuration of the pedestal member 31. Here, FIG. 4A is a perspective view of the pedestal member 31 viewed from the tip side, FIG. 4B is a top view of the pedestal member 31 viewed from the tip side, and FIG. 4C is a rear view of the pedestal member 31. The rear view seen from the end side is shown respectively.

The pedestal member 31 has a T-shaped vertical cross section and exhibits a top shape as a whole, and has a relatively large diameter on the rear end side and a relatively small diameter on the front end side. The pedestal member 31 is a kind of precipitation hardening type Ni—Cr alloy, and is composed of Nimonic 80A having excellent heat resistance and oxidation resistance. Therefore, the pedestal member 31 has conductivity.

The pedestal member 31 includes a base portion 314 and a protruding portion 315 formed so as to project from the central portion on the distal end side of the base portion 314 to the distal end side and having a diameter smaller than that of the base portion 314. Here, the base portion 314 is provided with a first through hole 311 and a second through hole 312, each of which penetrates from the front end side to the rear end side. Further, the pedestal member 31 is provided with a third through hole 313 that penetrates the base portion 314 and the protruding portion 315 from the front end side to the rear end side. As described above, the protruding portion 315 has a cylindrical shape due to the provision of the third through hole 313 inside. Here, when the third through hole 313 is centered, the first through hole 311 and the second through hole 312 are arranged at intervals of 120 °.

The base portion 314 as an example of the first facing portion or the sandwiching member is composed of a disk-shaped block in which stepped portions are formed on each of the front end side surface and the rear end side surface. Then, as shown in FIGS. 1 and 2, a part of the side surface of the base portion 314 is exposed to the outside without being covered by the housing portion 40 when the pressure detection device 20 is configured. There is.

The protruding portion 315 as an example of the connecting portion includes a thin-walled portion 315a provided on the tip end side of the base portion 314 and a thick-walled portion 315b provided on the tip end side of the thin-walled portion 315a and having a thickness thicker than that of the thin-walled portion 315a. Have. Here, the thickness of the thin portion 315a is 0.1 mm, and the thickness of the thick portion 315b is 0.3 mm. By reducing the thickness of the protruding portion 315 (particularly the thin-walled portion 315a) in this way, the protruding portion 315 functions as an elastic spring member. By adjusting the thickness of the thin portion 315a of the protruding portion 315, the spring constant of the protruding portion 315 can be set to a desired value. The elastic modulus (spring constant) of the protruding portion 315 is determined according to the preload applied to the piezoelectric element group 34, and the preload is set so that the piezoelectric element group 34 is not damaged when the preload is applied to the piezoelectric element group 34. Will be done. As is clear from FIGS. 2 and 3, since the inner diameter of the third through hole 313 provided in the base portion 314 is constant, the outer diameter of the thick portion 315b located on the tip side of the protruding portion 315 is constant. However, it is larger than the outer diameter of the thin-walled portion 315a located on the rear end side.

Here, the inner diameter of the third through hole 313 provided in the pedestal member 31 is larger than the inner diameter of each of the first through hole 311 and the second through hole 312. On the other hand, the inner diameters of the first through hole 311 and the second through hole 312 are equal.

Further, the inner diameter of the first through hole 311 is larger than the outer diameter of the rear end side electrode pin 38. Further, the inner diameter of the second through hole 312 is larger than the outer diameter of the tip side electrode pin 39.

(Insulation plate on the rear end side)
FIG. 5A shows a perspective view of the rear end side insulating plate 32 as viewed from the front end side.
The rear end side insulating plate 32 as an example of another insulating member is a member exhibiting an annular shape as a whole. The rear end side insulating plate 32 is made of a ceramic material having insulating properties and heat resistance (here, alumina ceramics).

Three groove portions (first groove portion 324, second groove portion 325, third groove portion 326: an example of another fragile portion) are formed radially on the surface on the tip end side of the rear end side insulating plate 32 at intervals of 120 °. Has been done. Further, in the rear end side insulating plate 32, a first through hole 321 that penetrates the rear end side insulating plate 32 from the front end side to the rear end side is provided at a portion that overlaps with the first groove portion 324. Further, a second through hole 322 that penetrates the rear end side insulating plate 32 from the front end side to the rear end side is provided at a portion of the rear end side insulating plate 32 that overlaps with the second groove portion 325. Further, a third through hole 323 that penetrates the rear end side insulating plate 32 from the front end side to the rear end side is provided in the central portion of the rear end side insulating plate 32. Here, when the third through hole 323 is centered, the first through hole 321 and the second through hole 322 are arranged at intervals of 120 °. In this example, only the first through holes 321 to the third through holes 323 are provided on the surface on the rear end side of the rear end side insulating plate 32, and the groove portion as described above is provided. Absent.

Here, the inner diameter of the third through hole 323 provided in the rear end side insulating plate 32 is larger than the inner diameter of each of the first through hole 321 and the second through hole 322. The inner diameters of the first through hole 321 and the second through hole 322 are equal.

Further, the inner diameter of the first through hole 321 is larger than the outer diameter of the rear end side electrode pin 38. Further, the inner diameter of the second through hole 322 is larger than the outer diameter of the tip side electrode pin 39. Furthermore, the inner diameter of the third through hole 323 is larger than the outer diameter of the protruding portion 315 (thick wall portion 315b) provided on the pedestal member 31. The outer diameter of the rear end side insulating plate 32 is smaller than the inner diameter of the front end side housing 41.

In the rear end side insulating plate 32, the third through hole 323 provided in the rear end side insulating plate 32 is inserted into the protruding portion 315 of the pedestal member 31 in a state where the surface provided with the first groove portion 324 or the like is directed toward the tip end side. As a result, it is held by the pedestal member 31. Then, the first through hole 321 provided in itself overlaps with the first through hole 311 provided in the base 314 of the pedestal member 31, and the second through hole 322 provided in itself is the pedestal member 31. The rear end side insulating plate 32 is positioned so as to overlap the second through hole 312 provided in the base portion 314. Here, the rear end side electrode pin 38 is inserted into the first through hole 321 and the front end side electrode pin 39 is inserted into the second through hole 322.

At this time, the surface of the rear end side insulating plate 32 on the rear end side is in contact with the surface of the pedestal member 31 on the front end side of the base portion 314. Further, the outer peripheral surface of the rear end side insulating plate 32 faces the inner peripheral surface of the front end side housing 41 of the housing portion 40 with a gap. Further, the inner peripheral surface of the first through hole 321 faces the outer peripheral surface of the rear end side electrode pin 38. Furthermore, the inner peripheral surface of the second through hole 322 faces the outer peripheral surface of the front end side electrode pin 39. The inner peripheral surface of the third through hole 323 faces the outer peripheral surface of the protruding portion 315 (thin-walled portion 315a) of the pedestal member 31 with a gap.

(Rear end side electrode plate)
FIG. 6A shows a perspective view of the rear end side electrode plate 33 as viewed from the front end side.
The rear end side electrode plate 33 as an example of another electrode member is a member exhibiting an annular shape as a whole. The rear end side electrode plate 33 is a kind of solid solution-treated Ni—Mo alloy, and is composed of Hastelloy B2 having excellent heat resistance and corrosion resistance of the welded portion. Therefore, the rear end side electrode plate 33 has conductivity.

The rear end side electrode plate 33 is provided with a first through hole 331 and a second through hole 332, each of which penetrates the rear end side electrode plate 33 from the front end side to the rear end side. Further, a third through hole 333 that penetrates the rear end side electrode plate 33 from the front end side to the rear end side is provided in the central portion of the rear end side electrode plate 33. Here, when the third through hole 333 is centered, the first through hole 331 and the second through hole 332 are arranged at intervals of 120 °.

Here, the inner diameter of the third through hole 333 provided in the rear end side electrode plate 33 is larger than the inner diameter of each of the first through hole 331 and the second through hole 332. The inner diameter of the second through hole 332 is larger than the inner diameter of the first through hole 331.

Further, the inner diameter of the first through hole 331 is substantially equal to the outer diameter of the rear end side electrode pin 38. Further, the inner diameter of the second through hole 332 is larger than the outer diameter of the tip side electrode pin 39. Furthermore, the inner diameter of the third through hole 333 is larger than the outer diameter of the protruding portion 315 (thick wall portion 315b) provided on the pedestal member 31. The outer diameter of the rear end side electrode plate 33 is smaller than the inner diameter of the front end side housing 41.

The rear end side electrode plate 33 has a third through hole 333 provided in the rear end side electrode plate 33 inserted into the protruding portion 315 of the pedestal member 31 with the surface shown in FIG. 6A facing the front end side. It is held by the pedestal member 31. Then, the first through hole 331 provided in itself overlaps with the first through hole 321 provided in the rear end side insulating plate 32, and the second through hole 332 provided in itself is insulated on the rear end side. The rear end side electrode plate 33 is positioned so as to overlap the second through hole 322 provided in the plate 32. Here, the rear end side electrode pin 38 is inserted into the first through hole 331, and the front end side electrode pin 39 is inserted into the second through hole 332.

At this time, the surface on the rear end side of the rear end side electrode plate 33 is in contact with the surface on the front end side of the rear end side insulating plate 32. Further, the outer peripheral surface of the rear end side electrode plate 33 faces the inner peripheral surface of the front end side housing 41 of the housing portion 40 with a gap. Further, the inner peripheral surface of the first through hole 331 faces the outer peripheral surface of the rear end side electrode pin 38. Furthermore, the inner peripheral surface of the second through hole 332 faces the outer peripheral surface of the front end side electrode pin 39 with a gap. The inner peripheral surface of the third through hole 333 faces the outer peripheral surface of the protruding portion 315 (thin-walled portion 315a) of the pedestal member 31 with a gap.

(Piezoelectric element group)
Next, the piezoelectric element group 34 will be described. Since the first piezoelectric element 341 to the third piezoelectric element 343 constituting the piezoelectric element group 34 have a common configuration, the first piezoelectric element 341 will be described here as an example.

FIG. 7 is a diagram for explaining the configuration of the first piezoelectric element 341. Here, FIG. 7A is a perspective view of the first piezoelectric element 341, and FIG. 7B is a sectional view taken along line VIIB-VIIB of FIG. 7A.

The first piezoelectric element 341 is a member having a rectangular parallelepiped shape and a plate shape as a whole. The first piezoelectric element 341 has a first pressure receiving surface 341a and a second pressure receiving surface 341b which are front and back surfaces, and a positive charge output surface 341c and a negative charge output surface 341d which are side surfaces facing each other. In the present embodiment, when the pressure detection device 20 (detection unit 30) is configured, the positive charge output surface 341c is located on the rear end side and the negative charge output surface 341d is located on the front end side. ..

Further, the first piezoelectric element 341 includes an element body 3411 made of a piezoelectric body, a positive electrode film 3412 formed on the element body 3411 so as to straddle the first pressure receiving surface 341a and the positive charge output surface 341c. It includes a negative electrode film 3413 formed so as to straddle the second pressure receiving surface 341b and the negative charge output surface 341d.

The element main body 3411 includes a piezoelectric body (piezoelectric single crystal in the present embodiment) that exhibits a piezoelectric action of a piezoelectric lateral effect. Here, the piezoelectric lateral effect means an action in which a charge is generated on the surface of the piezoelectric body in the direction of the charge generation axis when an external force is applied to the stress application axis located at a position orthogonal to the charge generation axis of the piezoelectric body. .. Examples of the piezoelectric single crystal include langateite-based crystals having a piezoelectric lateral effect (langasite, langateite, langanite, langatete (LTGA) in which a part of gallium is replaced with aluminum), quartz, gallium phosphate, and the like. Can be done. In this embodiment, a Langatate single crystal is used as the piezoelectric material.

As the positive electrode film 3142 and the negative electrode film 3413, plated gold (Au) was used, respectively.

The first piezoelectric element 341 to the third piezoelectric element 343 are located on the rear end side with their respective positive charge output surfaces 341c positioned on the rear end side and their respective negative charge output surfaces 341d on the front end side. It is held by being sandwiched between the electrode plate 33 and the tip side electrode plate 35. More specifically, in the present embodiment, the first component is applied to the piezoelectric element group 34 along the center line direction by using each component of the detection unit 30 excluding the piezoelectric element group 34. The piezoelectric elements 341 to the third piezoelectric element 343 are positioned (fixed). That is, these first piezoelectric elements 341 to the third piezoelectric elements 343 are not fixed by adhesion or the like.

Further, these first piezoelectric elements 341 to third piezoelectric elements 343 are arranged side by side along the circumferential direction of the rear end side electrode plate 33 and the front end side electrode plate 35.

At this time, the positive electrode film 3412 provided on the rear end side surface of each of the first piezoelectric element 341 to the third piezoelectric element 343, that is, the positive charge output surface 341c is the surface on the front end side of the rear end side electrode plate 33. Are in contact. Further, each of the first pressure receiving surfaces 341a of the first piezoelectric element 341 to the third piezoelectric element 343 faces the inner peripheral surface of the front end side housing 41 of the housing portion 40 with a gap. Further, each of the second pressure receiving surfaces 341b of the first piezoelectric element 341 to the third piezoelectric element 343 faces the outer peripheral surface of the protruding portion 315 (thin-walled portion 315a) of the pedestal member 31 with a gap. Furthermore, the first piezoelectric elements 341 to the third piezoelectric elements 343 face each other with a gap between them.

(Electrode plate on the tip side)
FIG. 6B shows a perspective view of the front end side electrode plate 35 as viewed from the rear end side.
The configuration of the front end side electrode plate 35 as an example of the electrode member is the same as that of the rear end side electrode plate 33 described above. Therefore, the tip side electrode plate 35 is provided with the first through hole 351 and the second through hole 352, and the third through hole 353, and when the third through hole 353 is the center, the first through hole 353 is provided. The through holes 351 and the second through holes 352 are arranged at intervals of 120 °.

Here, the inner diameter of the third through hole 353 provided in the front end side electrode plate 35 is larger than the inner diameter of each of the first through hole 351 and the second through hole 352. The inner diameter of the second through hole 352 is larger than the inner diameter of the first through hole 351.

Further, the inner diameter of the first through hole 351 is substantially equal to the outer diameter of the tip side electrode pin 39. Further, the inner diameter of the second through hole 352 is larger than the outer diameter of the rear end side electrode pin 38. Furthermore, the inner diameter of the third through hole 353 is larger than the outer diameter of the protruding portion 315 (thick wall portion 315b) provided on the pedestal member 31. The outer diameter of the tip-side electrode plate 35 is smaller than the inner diameter of the tip-side housing 41.

The front end side electrode plate 35 is provided with a third through hole 353 in a state where the surface shown in FIG. 6B is directed toward the rear end side (the front and back surfaces are interchanged with the rear end side electrode plate 33). Is inserted into the protruding portion 315 of the pedestal member 31 to be held by the pedestal member 31. Then, the first through hole 351 provided in itself overlaps with the second through hole 332 provided in the rear end side electrode plate 33, and the second through hole 352 provided in itself is the rear end side electrode. The tip side electrode plate 35 is positioned so as to overlap the first through hole 331 provided in the plate 33. Here, the tip side electrode pin 39 is inserted into the first through hole 351. On the other hand, the rear end side electrode pin 38 is not inserted into the second through hole 352.

At this time, the surface on the rear end side of the front end side electrode plate 35 comes into contact with the surface on the front end side of each of the first piezoelectric element 341 to the third piezoelectric element 343, that is, the negative electrode film 3413 provided on the negative charge output surface 341d. doing. Further, the outer peripheral surface of the front end side electrode plate 35 faces the inner peripheral surface of the front end side housing 41 of the housing portion 40 with a gap. Further, the inner peripheral surface of the first through hole 351 faces the outer peripheral surface of the front end side electrode pin 39. The inner peripheral surface of the third through hole 353 faces the outer peripheral surface of the protruding portion 315 (thin-walled portion 315a) of the pedestal member 31 with a gap.

(Insulation plate on the tip side)
FIG. 5B shows a perspective view of the front end side insulating plate 36 as viewed from the rear end side.
The configuration of the front end side insulating plate 36 as an example of the insulating member is the same as that of the rear end side insulating plate 32 described above. Therefore, the tip-side insulating plate 36 is provided with the first through hole 361 to the third through hole 363 and the first groove portion 364 to the third groove portion 366 (an example of the fragile portion), and the third through hole is provided. When 363 is the center, the first groove portion 364 to the third groove portion 366 are arranged at an interval of 120 °, and the first through hole 361 and the second through hole 362 are also arranged at an interval of 120 °. Further, the first through hole 361 is formed at a position overlapping the first groove portion 364, and the second through hole 362 is formed at a position overlapping the second groove portion 365.

Here, the inner diameter of the third through hole 363 provided in the front end side insulating plate 36 is larger than the inner diameter of each of the first through hole 361 and the second through hole 362. The inner diameters of the first through hole 361 and the second through hole 362 are equal.

Further, the inner diameter of the first through hole 361 is larger than the outer diameter of the tip side electrode pin 39. Further, the inner diameter of the second through hole 362 is larger than the outer diameter of the rear end side electrode pin 38. Furthermore, the inner diameter of the third through hole 363 is larger than the outer diameter of the protruding portion 315 (thick wall portion 315b) provided on the pedestal member 31. The outer diameter of the tip-side insulating plate 36 is smaller than the inner diameter of the tip-side housing 41.

The front end side insulating plate 36 is provided with a third through hole 363 in a state where the surface shown in FIG. 5B is directed toward the rear end side (a state in which the front and back surfaces are interchanged with the rear end side insulating plate 32). Is inserted into the protruding portion 315 of the pedestal member 31 to be held by the pedestal member 31. Then, the first through hole 361 provided in itself overlaps with the first through hole 351 provided in the tip side electrode plate 35, and the second through hole 362 provided in itself overlaps with the first through hole 351 provided in the tip side electrode plate 35. The tip side insulating plate 36 is positioned so as to overlap with the second through hole 352 provided in the above. Here, the tip side electrode pin 39 is inserted into the first through hole 361. On the other hand, the rear end side electrode pin 38 is not inserted into the second through hole 362.

(Pressure applying member)
FIG. 8 shows a perspective view of the pressure applying member 37 as viewed from the tip side.
The pressure applying member 37 as an example of the second facing portion or the supporting member is a member having a cylindrical shape as a whole. The pressure applying member 37 is made of the same nymonic 80A as the pedestal member 31. Therefore, the pressure applying member 37 has conductivity.

The pressure applying member 37 includes an edge portion 371 provided on the peripheral edge on the front end side, and a recess 372 recessed inside the edge end portion 371 on the rear end side (back side) of the edge end portion 371. The pressure applying member 37 is provided with a through hole 373 that penetrates the recess 372 of the pressure applying member 37 from the front end side to the rear end side.

Here, the inner diameter of the through hole 373 provided in the pressure applying member 37 is slightly larger than the outer diameter of the protruding portion 315 (thick wall portion 315b) provided in the pedestal member 31. The outer diameter of the pressure applying member 37 is smaller than the inner diameter of the tip-side housing 41.

The pressure applying member 37 is a pedestal by inserting a through hole 373 provided in the pressure applying member 37 into the protruding portion 315 of the pedestal member 31 in a state where the surface provided with the edge end portion 371 or the like is directed toward the tip end side. It is held by the member 31. Then, the pressure applying member 37 and the pedestal member 31 (protruding portion) face each other with the inner peripheral surface of the through hole 373 of the pressure applying member 37 and the outer peripheral surface of the thick portion 315b of the protruding portion 315 of the pedestal member 31. By welding with 315), the pressure applying member 37 is positioned and fixed to the pedestal member 31. Further, the rear end side insulating plate 32, the rear end side electrode plate 33, the piezoelectric element group 34, the front end side electrode plate 35 and the front end side insulating plate 36 are sandwiched between the base portion 314 of the pedestal member 31 and the pressure applying member 37. As a result, a preload is applied to each of the first piezoelectric element 341 to the third piezoelectric element 343 constituting the piezoelectric element group 34.

At this time, the surface on the rear end side of the pressure applying member 37 is in contact with the surface on the front end side of the front end side insulating plate 36. Further, the outer peripheral surface of the pressure applying member 37 faces the inner peripheral surface of the front end side housing 41 of the housing portion 40 with a gap. Further, the inner peripheral surface of the through hole 373 faces the outer peripheral surface of the protruding portion 315 (thick wall portion 315b) of the pedestal member 31.

(Rear end side electrode pin)
The rear end side electrode pin 38 is a member having a columnar shape and a rod shape as a whole. The rear end side electrode pin 38 is made of a Udymet Alloy 188.

The rear end side electrode pins 38 are provided in the first through hole 311 provided in the base portion 314 of the pedestal member 31, the first through hole 321 provided in the rear end side insulating plate 32, and the rear end side electrode plate 33. It is arranged through the first through hole 331. The rear end side electrode pin 38 is inserted into an insulating ring member (not shown) made of ceramics having a cylindrical shape inside the first through hole 311 provided in the base portion 314 of the pedestal member 31. It is installed. This insulating ring member prevents contact (short circuit) between the rear end side electrode pin 38 and the pedestal member 31. Then, by welding the front end side of the rear end side electrode pin 38 to the rear end side electrode plate 33, conduction is established between the two, and the rear end side electrode pin 38 is positioned with respect to the rear end side electrode plate 33. And fixed.

(Electrode pin on the tip side)
The tip side electrode pin 39 is a member having a columnar shape and a rod shape as a whole. The configuration of the front end side electrode pin 39 is the same as that of the rear end side electrode pin 38 described above, except that the length in the center line direction is longer than that of the rear end side electrode pin 38.

The front end side electrode pins 39 are provided in the second through hole 312 provided in the base portion 314 of the pedestal member 31, the second through hole 322 provided in the rear end side insulating plate 32, and the rear end side electrode plate 33. It is arranged through the two through holes 332, the first through hole 351 provided in the distal electrode plate 35, and the first through hole 361 provided in the distal insulating plate 36. The tip side electrode pin 39 is mounted in a state of being inserted into an insulating ring member (not shown) made of ceramics having a cylindrical shape inside a second through hole 312 provided in the base portion 314 of the pedestal member 31. Will be done. This insulating ring member prevents contact (short circuit) between the tip side electrode pin 39 and the pedestal member 31. Then, the tip side of the tip side electrode pin 39 is welded to the tip side electrode plate 35 to establish conduction between the two, and the tip side electrode pin 39 is positioned and fixed to the tip side electrode plate 35. ing.

[Positional relationship between rear end side insulation plate, piezoelectric element group and front end side insulation plate]
Here, the positional relationship between the rear end side insulating plate 32, the piezoelectric element group 34, and the front end side insulating plate 36 in the detection unit 30 will be described.

In the detection unit 30, the front end side surface of the rear end side insulating plate 32 provided with the first groove portion 324 to the third groove portion 326 and the first groove portion 364 to the third groove portion 366 of the front end side insulating plate 36 are provided. The surface on the rear end side is facing each other. Then, the rear end side electrode plate 33, the piezoelectric element group 34, and the front end side electrode plate 35 are arranged in this order between the rear end side insulating plate 32 and the front end side insulating plate 36. At this time, the first groove portion 324 of the rear end side insulating plate 32 and the second groove portion 365 of the front end side insulating plate 36 face each other, and the second groove portion 325 of the rear end side insulating plate 32 and the first of the front end side insulating plate 36. The groove portion 364 faces each other, and the third groove portion 326 of the rear end side insulating plate 32 and the third groove portion 366 of the front end side insulating plate 36 face each other. Further, the first through hole 321 of the rear end side insulating plate 32 and the second through hole 362 of the front end side insulating plate 36 face each other, and the second through hole 322 of the rear end side insulating plate 32 and the front end side insulating plate 36 The first through hole 361 faces each other, and the third through hole 323 of the rear end side insulating plate 32 and the third through hole 363 of the front end side insulating plate 36 face each other.

FIG. 9A is a diagram for explaining the positional relationship between the rear end side insulating plate 32 and the first piezoelectric element 341 to the third piezoelectric element 343. Here, FIG. 9A is a view of the rear end side insulating plate 32 as viewed from the front end side. As described above, the rear end side electrode plate 33 actually exists between the rear end side insulating plate 32 and the first piezoelectric element 341 to the third piezoelectric element 343.

First, the first piezoelectric element 341 is arranged so as to face a flat portion sandwiched between the first groove portion 324 and the third groove portion 326 on the front end side surface of the rear end side insulating plate 32. Further, the second piezoelectric element 342 is arranged so as to face a flat portion sandwiched between the second groove portion 325 and the third groove portion 326 on the front end side surface of the rear end side insulating plate 32. Further, the third piezoelectric element 343 is arranged so as to face a flat portion sandwiched between the first groove portion 324 and the second groove portion 325 on the front end side surface of the rear end side insulating plate 32.

FIG. 9B is a diagram for explaining the positional relationship between the tip-side insulating plate 36 and the first piezoelectric element 341 to the third piezoelectric element 343. Here, FIG. 9B is a view of the front end side insulating plate 36 as viewed from the rear end side. As described above, the tip side electrode plate 35 actually exists between the tip side insulating plate 36 and the first piezoelectric element 341 to the third piezoelectric element 343.

First, the first piezoelectric element 341 is arranged so as to face a flat portion sandwiched between the second groove portion 365 and the third groove portion 366 on the rear end side surface of the front end side insulating plate 36. Further, the second piezoelectric element 342 is arranged so as to face a flat portion sandwiched between the first groove portion 364 and the third groove portion 366 on the rear end side surface of the front end side insulating plate 36. Further, the third piezoelectric element 343 is arranged so as to face a flat portion sandwiched between the first groove portion 364 and the second groove portion 365 on the rear end side surface of the front end side insulating plate 36.

Therefore, the first piezoelectric element 341 has a flat portion existing between the first groove portion 324 and the third groove portion 326 of the rear end side insulating plate 32, and the second groove portion 365 and the second groove portion 365 of the front end side insulating plate 36. It is sandwiched between a flat portion existing between the three groove portions 366. Further, the second piezoelectric element 342 has a flat portion existing between the second groove portion 325 and the third groove portion 326 of the rear end side insulating plate 32, and the first groove portion 364 and the first groove portion 364 of the front end side insulating plate 36. It is sandwiched between a flat portion existing between the three groove portions 366. Further, the third piezoelectric element 343 has a flat portion existing between the first groove portion 324 and the second groove portion 325 of the rear end side insulating plate 32, and the first groove portion 364 and the first groove portion 364 of the front end side insulating plate 36. It is sandwiched between a flat portion existing between the two grooves 365. In this way, all the first piezoelectric elements 341 to the third piezoelectric elements 343 are arranged so as to face the portions of the rear end side insulating plate 32 and the front end side insulating plate 36 where no grooves or through holes are formed. It will be done.

Here, when viewed from the tip-side insulating plate 36, in the tip-side insulating plate 36, the first through holes 361 to the third through holes 363 and the first through holes 363 and the first through holes 363 and the first through holes 363 and the first through holes 363 and the first through holes 363 and the first through holes 363 and the first through holes 363 and the first through holes 363 The groove portion 364 to the third groove portion 366 are formed. Further, when viewed from the rear end side insulating plate 32, in the rear end side insulating plate 32, the first through holes 321 to the third through holes 323 and the third through holes 323 and the third through holes 323 and the third through holes 323 and the third through holes 323 and the third through holes 323 and the third through holes 323 and the third through holes 323 and The 1-groove portion 324 to the 3rd groove portion 326 are formed.

[Applying preload to piezoelectric element group]
Next, the application of the preload to the piezoelectric element group 34 in the detection unit 30 will be described.

For example, when the pressure detection device 20 of the present embodiment is attached to a gas turbine engine and used, the transmission unit 50 is exposed to a high temperature environment of 500 ° C. to 600 ° C. Further, since the gas turbine engine is continuously burned, unlike the reciprocating engine, the temperature fluctuation during operation is small. Therefore, when the gas turbine engine is in operation, each member constituting the detection unit 30 provided in the pressure detection device 20 undergoes thermal expansion due to heating, and the thermal expansion state is maintained. ..

In the detection unit 30 of the present embodiment, as described above, the first piezoelectric element 341 to the third piezoelectric element 343 constituting the piezoelectric element group 34 are attached to the front end side and the rear end side without using a technique such as adhesion. It is fixed by sandwiching it from the side. Then, when the detection unit 30 is heated, the force for sandwiching the first piezoelectric element 341 to the third piezoelectric element 343 is generated due to the difference in the coefficient of thermal expansion of each member (metal or ceramics) constituting the detection unit 30. May be weakened.

If the force for sandwiching the first piezoelectric element 341 to the third piezoelectric element 343 becomes too weak, the positions of the first piezoelectric element 341 to the third piezoelectric element 343 in the detection unit 30 may shift, or the first piezoelectric element 30 may shift from the detection unit 30. There is a risk that the elements 341 to the third piezoelectric element 343 may fall off.

Therefore, in the detection unit 30, in the initial state before the pressure is detected, a load of a predetermined size is applied to each of the first piezoelectric element 341 to the third piezoelectric element 343 constituting the piezoelectric element group 34. Preload) is given.

In the detection unit 30, the rear end side electrode plate 33, the rear end side insulating plate 32, and the base portion 314 of the pedestal member 31 are arranged in this order on the rear end side (positive electrode side) of the piezoelectric element group 34. On the other hand, in the detection unit 30, the tip side electrode plate 35, the tip side insulating plate 36, and the pressure applying member 37 are arranged in this order on the tip side (negative electrode side) of the piezoelectric element group 34. Then, in the detection unit 30, the base portion 314 of the pedestal member 31 located on the rearmost end side and the pressure applying member 37 located on the most tip side are welded to the protruding portion 315 of the pedestal member 31 and the pressure applying member 37. It is integrated with. Here, the protruding portion 315 is made of a cylindrical metal material (Nimonic 80A) as described above, and functions as a spring member (pulling spring) that acts in the direction of bringing the base portion 314 and the pressure applying member 37 closer to each other. ..

Then, in the present embodiment, as will be described later, the protruding portion 315 is contracted with respect to the center line direction by irradiating the protruding portion 315 of the pedestal member 31 with the laser irradiation in the state where the detection unit 30 is assembled. .. As a result, each of the first piezoelectric element 341 to the third piezoelectric element 343 constituting the piezoelectric element group 34 is centered by increasing the force of sandwiching the first piezoelectric element 341 to the third piezoelectric element 343 from the front end side and the rear end side by the members constituting the detection unit 30. A preload along the linear direction will be applied.

[Configuration of housing]
The housing portion 40 includes a front end side housing 41 that houses the front end side of the detection unit 30 inside, and a rear end side housing 42 that is attached to the rear end side of the detection unit 30.

(Front end housing)
The tip-side housing 41 is a member having a cylindrical shape as a whole. The tip-side housing 41 is made of Nimonic 80A.

Here, the inner diameter of the tip-side housing 41 is the outer diameter of the portion of the detection portion 30 that is on the tip side of the base portion 314 of the pedestal member 31 and the outside of the pressure distribution plate 52 (details will be described later) in the transmission portion 50. Larger than the diameter. Further, the outer diameter of the tip-side housing 41 is smaller than that of the base portion 314 of the pedestal member 31 having the largest outer diameter.

The front end side surface of the front end side housing 41 is in contact with the rear end side surface of the diaphragm head 51 (details will be described later) in the transmission unit 50. Here, the boundary between the front end side of the front end side housing 41 and the rear end side of the diaphragm head 51 is joined by laser welding over the entire circumference. Further, the rear end side surface of the front end side housing 41 is in contact with the front end side surface of the base portion 314 of the pedestal member 31 in the detection unit 30. Here, the boundary between the rear end side of the front end side housing 41 and the front end side of the base portion 314 of the pedestal member 31 is joined by laser welding over the entire circumference.

(Rear end side housing)
The rear end side housing 42 is a member having a cylindrical shape as a whole. The rear end side housing 42 is made of Nimonic 80A.

Here, the inner diameter of the rear end side housing 42 is larger than the outer diameter of the cable housing 65 (details will be described later) in the output unit 60. Further, the outer diameter of the rear end side housing 42 is smaller than the portion having the largest outer diameter in the base portion 314 of the pedestal member 31.

The front end side surface of the rear end side housing 42 is in contact with the rear end side surface of the base portion 314 of the pedestal member 31 in the detection unit 30. Here, the boundary between the front end side of the rear end side housing 42 and the rear end side of the base portion 314 of the pedestal member 31 is joined by laser welding over the entire circumference. Further, the rear end side surface of the rear end side housing 42 is in contact with the front end side surface of the cable housing 65 in the output unit 60. Here, the boundary between the rear end side of the rear end side housing 42 and the front end side of the cable housing 65 is joined by laser welding over the entire circumference.

[Composition of transmission unit]
The transmission unit 50 includes a diaphragm head 51 attached to the front end side of the front end side housing 41, and a pressure applying member 37 inside the front end side housing 41 on the rear end side of the diaphragm head 51 and on the detection unit 30. It is provided with a pressure distribution plate 52 attached to the. Therefore, the pressure distribution plate 52 is housed inside the front end side housing 41.

(Diaphragm head)
The diaphragm head 51 is a member having a disk shape as a whole. The diaphragm head 51 is made of Nimonic 80A.

Here, the outer diameter of the diaphragm head 51 is the same as the outer diameter of the front end side housing 41. In this example, the outer diameter of the diaphragm head 51 is about 8 mm.

The surface of the diaphragm head 51 on the tip end side is exposed to the outside. Further, of the surface on the rear end side of the diaphragm head 51, the portion on the peripheral edge side is in contact with the surface on the front end side of the front end side housing 41. Further, of the surface on the rear end side of the diaphragm head 51, the portion on the center side is in contact with the surface on the front end side of the pressure distribution plate 52. Here, the boundary between the diaphragm head 51 and the tip side of the tip side housing 41 is joined by laser welding over the entire circumference.

(Pressure dispersion plate)
The pressure distribution plate 52 is a member having a disk shape as a whole. The pressure distribution plate 52 is composed of the same nymonic 80A as the pedestal member 31 and the pressure applying member 37.

Here, the outer diameter of the pressure distribution plate 52 is slightly smaller than the inner diameter of the recess 372 provided in the pressure applying member 37. The pressure distribution plate 52 is fitted into the recess 372 provided in the pressure applying member 37.

The surface of the pressure distribution plate 52 on the front end side is in contact with the surface on the rear end side and the center side of the diaphragm head 51. Further, of the surface on the rear end side of the pressure distribution plate 52, the portion on the peripheral edge side is in contact with the recess 372 provided on the front end side of the pressure applying member 37. Further, of the surface on the rear end side of the pressure distribution plate 52, the portion on the center side faces the through hole 373 provided in the pressure applying member 37 (the third through hole 313 provided in the pedestal member 31). ing.

[Output section configuration]
The output unit 60 includes a first cable 61 connected to the rear end side electrode pin 38 and a second cable 62 connected to the front end side electrode pin 39 on the rear end side of the detection unit 30. Further, the output unit 60 is arranged inside the rear end side housing 42, and includes a first connection sleeve 63 for connecting the rear end side electrode pin 38 and the core wire of the first cable 61, and a front end side electrode pin 39. A second connection sleeve 64 for connecting the core wire of the second cable 62 is provided. Further, the output unit 60 has a cable housing 65 for accommodating the first cable 61 and the second cable 62 inside and a cable housing 65 on the rear end side of the first connection sleeve 63 and the second connection sleeve 64. A holding member 66 for holding the first cable 61 and the second cable 62, and inclusions 67 for fixing the first cable 61 and the second cable 62 inside the holding member 66 are provided inside the holding member 66.

(1st cable)
The first cable 61 is a member that exhibits a linear shape as a whole. The first cable 61 is an MI (Mineral Insulated) cable in which a metal core wire is arranged inside a metal tubular sheath and an inorganic insulator is filled between the sheath and the core wire. It is configured.
A core wire is exposed on the tip end side of the first cable 61, and this core wire is connected to the rear end side of the rear end side electrode pin 38 via the first connection sleeve 63. On the other hand, the rear end side of the first cable 61 is exposed to the outside, and can be connected to an external device (not shown).

(2nd cable)
The second cable 62 is configured to be the same as the first cable 61.
A core wire is exposed on the tip end side of the second cable 62, and this core wire is connected to the rear end side of the front end side electrode pin 39 via the second connection sleeve 64. On the other hand, the rear end side of the second cable 62 is exposed to the outside, and can be connected to an external device (not shown).

(1st connection sleeve)
The first connection sleeve 63 is a member having a cylindrical shape as a whole. The first connection sleeve 63 is composed of a nymonic 80A.
Inside the first connection sleeve 63, the rear end side of the rear end side electrode pin 38 and the tip side of the core wire of the first cable 61 are arranged, and by crimping the first connection sleeve 63, these are arranged. Are electrically connected and fixed.

(2nd connection sleeve)
The second connection sleeve 64 is made of the same material as the first connection sleeve 63.
Inside the second connection sleeve 64, the rear end side of the tip side electrode pin 39 and the tip side of the core wire of the second cable 62 are arranged, and these can be crimped by crimping the second connection sleeve 64. It is electrically connected and fixed.

(Cable housing)
The cable housing 65 is a member having a cylindrical shape as a whole. The cable housing 65 is made of Nimonic 80A.
The front end side surface of the cable housing 65 is in contact with the rear end side surface of the rear end side housing 42. Here, the boundary between the front end side of the cable housing 65 and the rear end side of the rear end side housing 42 is joined by laser welding over the entire circumference.

(Holding member)
The holding member 66 is a member having a cylindrical shape as a whole. The holding member 66 is made of Inconel.
The front end side surface of the holding member 66 faces the rear end side surface of the pedestal member 31 inside the rear end side housing 42. Further, the surface of the holding member 66 on the rear end side is exposed to the outside. Further, the outer peripheral surface of the holding member 66 is in contact with the inner peripheral surface of the cable housing 65. Furthermore, the inner peripheral surface of the holding member 66 is in contact with the inclusions 67.

(Intercession)
The inclusions 67 are deformable members. The inclusion 67 is composed of SiO ₂ .
The inclusions 67 fill the gaps existing inside the holding member 66 between the inner peripheral surface of the holding member 66 and the first cable 61 and the second cable 62.

[Electrical connection structure in pressure detector]
Next, the electrical connection structure of the pressure detection device 20 will be described.

(Positive route)
In the pressure detection device 20, the rear end side of each of the first piezoelectric element 341 to the third piezoelectric element 343 (the positive charge output surface 341c side of the first piezoelectric element 341) constituting the piezoelectric element group 34 is made of metal. It is electrically connected to the tip end side of the end side electrode plate 33. Further, the rear end side electrode plate 33 is electrically connected to the front end side of the metal rear end side electrode pin 38. Further, the rear end side of the rear end side electrode pin 38 is electrically connected to the metal core wire exposed on the tip end side of the first cable 61 via the metal first connection sleeve 63. The rear end side of the first cable 61 extends to the rear end side of the cable housing 65 and is exposed to the outside. Hereinafter, the electrical path from the rear end side surface of the piezoelectric element group 34 to the core wire of the first cable 61 will be referred to as a “positive path”.

(Negative route)
On the other hand, in the pressure detection device 20, the tip side of each of the first piezoelectric element 341 to the third piezoelectric element 343 (the negative charge output surface 341d side of the first piezoelectric element 341) constituting the piezoelectric element group 34 is made of metal. It is electrically connected to the rear end side of the front end side electrode plate 35. Further, the tip side electrode plate 35 is electrically connected to the tip side of the metal tip side electrode pin 39. Further, the rear end side of the front end side electrode pin 39 is electrically connected to the metal core wire exposed on the front end side of the second cable 62 via the metal second connection sleeve 64. The rear end side of the second cable 62 extends to the rear end side of the cable housing 65 and is exposed to the outside. Hereinafter, the electrical path from the front end side surface of the piezoelectric element group 34 to the core wire of the second cable 62 will be referred to as a “negative path”.

(Case route)
On the other hand, in the pressure detection device 20, the inside of the metal cable housing 65 is electrically connected to the outside of the metal holding member 66. Further, the front end side of the cable housing 65 is electrically connected to the rear end side of the metal rear end side housing 42. Further, the front end side of the rear end side housing 42 is electrically connected to the rear end side of the base portion 314 of the metal pedestal member 31. Furthermore, the tip end side of the base 314 of the pedestal member 31 is electrically connected to the rear end side of the metal tip side housing 41. Further, the tip side of the tip side housing 41 is electrically connected to the rear end side and the peripheral edge side of the metal diaphragm head 51. Further, the rear end side and the center side of the diaphragm head 51 are electrically connected to the tip end side of the metal pressure distribution plate 52. Furthermore, the rear end side and the peripheral side of the pressure distribution plate 52 are electrically connected to the tip end side of the metal pressure applying member 37. Then, the inner peripheral surface of the through hole 373 provided in the pressure applying member 37 is electrically connected to the outer peripheral surface of the protruding portion 315 (thick wall portion 315b) of the metal pedestal member 31. Hereinafter, the electrical path including the housing unit 40, the transmission unit 50, a part of the detection unit 30, and a part of the output unit 60 will be referred to as a “housing path”.

(Relationship between routes)
First, the positive path and the negative path include an air gap existing inside the pressure detection device 20, an inorganic insulator provided on the first cable 61, and an inorganic insulator provided on the second cable 62. Is electrically insulated by.
Next, the positive path and the housing path are electrically formed by the air gap existing inside the pressure detection device 20, the rear end side insulating plate 32, and the inorganic insulator provided in the first cable 61. Insulated in.
The negative path and the housing path are electrically insulated by the air gap existing inside the pressure detection device 20, the tip side insulating plate 36, and the inorganic insulator provided in the second cable 62. Has been done.

In the pressure detection device 20 of the present embodiment, the positive path, the negative path, and the housing path are electrically insulated from each other. By adopting such a configuration, in this pressure detection device 20, it is possible to prevent electrical noise entering the housing path from a mounting target such as a jet engine from entering the positive path and the negative path. doing.

As is clear from the above description, in the pressure detection device 20, the first piezoelectric elements 341 to the third piezoelectric elements 343 constituting the piezoelectric element group 34 are connected in parallel. In the pressure detection device 20 of the present embodiment, by using a plurality of piezoelectric elements, the amount of electric charge output as the pressure changes is increased, and the sensitivity for detecting the pressure is increased.

[Manufacturing method of detector]
FIG. 10 is a flowchart showing a manufacturing procedure of the detection unit 30 constituting the pressure detection device 20.

(Electrode pin mounting process)
First, the pedestal member 31 is set on the assembling table with the base portion 314 positioned downward and the protruding portion 315 positioned upward. Then, the rear end side electrode pin 38 and the front end side electrode pin 39 are attached to the pedestal member 31 (step 10). In step 10, the rear end side electrode pin 38 is inserted into the first through hole 311 of the pedestal member 31, and the front end side electrode pin 39 is inserted into the second through hole 312 of the pedestal member 31 from above the pedestal member 31. The rear end side electrode pin 38 and the front end side electrode pin 39 are pre-mounted with an insulating ring member made of ceramics having a cylindrical shape, and are attached to the pedestal member 31 via the insulating ring member. Then, using a jig (not shown), the positions of the rear end side electrode pin 38 and the front end side electrode pin 39 with respect to the pedestal member 31 are temporarily fixed. At this time, the tip of the front end side electrode pin 39 is arranged above the tip of the rear end side electrode pin 38.

(Rear end side insulation plate mounting process)
Next, the rear end side insulating plate 32 is attached to the pedestal member 31 (step 20). In step 20, the rear end side electrode pin 38 is inserted into the first through hole 321 of the rear end side insulating plate 32 from above the pedestal member 31, and the front end side electrode is inserted into the second through hole 322 of the rear end side insulating plate 32. The pin 39 is inserted, and the protruding portion 315 of the pedestal member 31 is inserted into the third through hole 323 of the rear end side insulating plate 32. As a result, the rear end side insulating plate 32 is loaded on the base portion 314 of the pedestal member 31. At this time, the first groove portion 324 to the third groove portion 326 provided on the rear end side insulating plate 32 face upward, that is, the side opposite to the base portion 314. Further, the inner peripheral surface of the first through hole 321 of the rear end side insulating plate 32 faces the outer peripheral surface of the rear end side electrode pin 38 with a gap. Further, the inner peripheral surface of the second through hole 322 of the rear end side insulating plate 32 faces the outer peripheral surface of the front end side electrode pin 39 with a gap. Furthermore, the inner peripheral surface of the third through hole 323 of the rear end side insulating plate 32 faces the outer peripheral surface of the protruding portion 315 with a gap.

(Rear end side electrode plate mounting process)
Subsequently, the rear end side electrode plate 33 is attached to the pedestal member 31 (step 30). In step 30, the rear end side electrode pin 38 is inserted into the first through hole 331 of the rear end side electrode plate 33 from above the pedestal member 31, and the front end side electrode is inserted into the second through hole 332 of the rear end side electrode plate 33. The pin 39 is inserted, and the protruding portion 315 of the pedestal member 31 is inserted into the third through hole 333 of the rear end side electrode plate 33. As a result, the rear end side electrode plate 33 is loaded on the rear end side insulating plate 32. At this time, the inner peripheral surface of the first through hole 331 of the rear end side electrode plate 33 faces the outer peripheral surface of the rear end side electrode pin 38. Further, the outer peripheral surface of the second through hole 332 of the rear end side electrode plate 33 faces the outer peripheral surface of the front end side electrode pin 39 with a gap. Further, the outer peripheral surface of the third through hole 333 of the rear end side electrode plate 33 faces the outer peripheral surface of the protruding portion 315 with a gap.

(Piezoelectric element group installation process)
Next, the first piezoelectric element 341 to the third piezoelectric element 343 constituting the piezoelectric element group 34 are installed on the rear end side electrode plate 33 (step 40).

In step 40, first, with the positive charge output surface 341c positioned downward and the negative charge output surface 341d positioned upward, the first piezoelectric element 341 is placed on the front end side (upper side) of the rear end side electrode plate 33. It is installed in a region of the rear end side insulating plate 32 that faces a flat portion sandwiched between the first groove portion 324 and the third groove portion 326 (see FIG. 9A). At this time, the first piezoelectric element 341 is installed so that the longitudinal direction of the positive charge output surface 341c follows the circumferential direction of the rear end side electrode plate 33. As a result, the first piezoelectric element 341 is loaded on the rear end side electrode plate 33, the positive charge output surface 341c is in contact with the rear end side electrode plate 33, and the negative charge output surface 341d faces vertically upward. Become. Then, in this state, the first piezoelectric element 341 is temporarily fixed by a jig (not shown).

In step 40, next, the second piezoelectric element 342 is placed on the front end side (upper side) of the rear end side electrode plate 33 with the positive charge output surface 341c positioned downward and the negative charge output surface 341d located upward. It is installed in a region of the rear end side insulating plate 32 facing a flat portion sandwiched between the second groove portion 325 and the third groove portion 326 (see FIG. 9A). At this time, the second piezoelectric element 342 is installed so that the longitudinal direction of the positive charge output surface 341c follows the circumferential direction of the rear end side electrode plate 33. As a result, the second piezoelectric element 342 is loaded on the rear end side electrode plate 33, the positive charge output surface 341c is in contact with the rear end side electrode plate 33, and the negative charge output surface 341d faces vertically upward. Become. Then, the second piezoelectric element 342 is temporarily fixed in this state by a jig (not shown).

In step 40, the third piezoelectric element 343 is subsequently placed on the front end side (upper side) of the rear end side electrode plate 33 with the positive charge output surface 341c positioned downward and the negative charge output surface 341d positioned upward. It is installed in a region of the rear end side insulating plate 32 facing a flat portion sandwiched between the first groove portion 324 and the second groove portion 325 (see FIG. 9A). At this time, the third piezoelectric element 343 is installed so that the longitudinal direction of the positive charge output surface 341c follows the circumferential direction of the rear end side electrode plate 33. As a result, the third piezoelectric element 343 is loaded on the rear end side electrode plate 33, the positive charge output surface 341c is in contact with the rear end side electrode plate 33, and the negative charge output surface 341d faces vertically upward. Become. Then, the third piezoelectric element 343 is temporarily fixed in this state by a jig (not shown).

In the piezoelectric element group 34 installed in this way, the first piezoelectric elements 341 to the third piezoelectric elements 343 are arranged at intervals of 120 ° from each other. Further, the first piezoelectric element 341 to the third piezoelectric element 343 are arranged so as to surround the protruding portion 315 of the pedestal member 31. Further, since the first piezoelectric elements 341 to the third piezoelectric elements 343 are arranged so as to sandwich the first groove portion 324 to the third groove portion 326, they are not in contact with each other.

(Tip side electrode plate mounting process)
Next, the tip side electrode plate 35 is attached to the pedestal member 31 (step 50). In step 50, the tip side electrode pin 39 is inserted into the first through hole 351 of the tip side electrode plate 35 from above the pedestal member 31, and the protruding portion of the pedestal member 31 is inserted into the third through hole 353 of the tip side electrode plate 35. Insert 315. Since the rear end side electrode pin 38 does not reach the front end side electrode plate 35, nothing is particularly inserted into the second through hole 352 of the front end side electrode plate 35. As a result, the front end side electrode plate 35 is loaded on the first piezoelectric element 341 to the third piezoelectric element 343 constituting the piezoelectric element group 34. At this time, the negative charge output surfaces 341d provided on each of the first piezoelectric element 341 to the third piezoelectric element 343 come into contact with the rear end side (lower side) surface of the front end side electrode plate 35. Further, the inner peripheral surface of the first through hole 351 of the distal electrode plate 35 faces the outer peripheral surface of the distal electrode pin 39. Further, the inner peripheral surface of the second through hole 352 of the tip side electrode plate 35 faces the void. Furthermore, the inner peripheral surface of the third through hole 353 of the front end side electrode plate 35 faces the outer peripheral surface of the protruding portion 315 with a gap.

(Insulation plate mounting process on the tip side)
Subsequently, the tip side insulating plate 36 is attached to the pedestal member 31 (step 60). In step 60, the tip side electrode pin 39 is inserted into the first through hole 361 of the tip side insulating plate 36 from above the pedestal member 31, and the protruding portion of the pedestal member 31 is inserted into the third through hole 363 of the tip side insulating plate 36. Insert 315. Since the rear end side electrode pin 38 does not reach the front end side insulating plate 36, nothing is particularly inserted into the second through hole 362 of the front end side insulating plate 36. As a result, the tip-side insulating plate 36 is loaded on the tip-side electrode plate 35. At this time, the first groove portion 364 to the third groove portion 366 provided on the front end side insulating plate 36 face downward, that is, the front end side electrode plate 35 side. Further, the inner peripheral surface of the first through hole 361 of the front end side insulating plate 36 faces the outer peripheral surface of the front end side electrode pin 39 with a gap. Further, the inner peripheral surface of the second through hole 362 of the front end side insulating plate 36 faces the void. Furthermore, the inner peripheral surface of the third through hole 363 of the front end side insulating plate 36 faces the outer peripheral surface of the protruding portion 315 with a gap.

(Pressure applying member mounting process)
Next, the pressure applying member 37 is attached to the pedestal member 31 (step 70). In step 70, with the recess 372 of the pressure applying member 37 facing upward, the pressure applying member 37 is inserted into the through hole 373 of the pressure applying member 37 from above the pedestal member 31. To do. As a result, the pressure applying member 37 is loaded on the front end side insulating plate 36. At this time, the inner peripheral surface of the through hole 373 of the pressure applying member 37 faces the outer peripheral surface of the thick portion 315b of the protruding portion 315 of the pedestal member 31. Then, the pressure applying member 37 is temporarily fixed in this state by a jig (not shown).

(Laser welding process)
Then, the pedestal member 31 includes a rear end side insulating plate 32, a rear end side electrode plate 33, a piezoelectric element group 34, a front end side electrode plate 35, a front end side insulating plate 36, a pressure applying member 37, a rear end side electrode pin 38, and the like. With the front end side electrode pin 39 attached, the protruding portion 315 of the pedestal member 31 and the pressure applying member 37 are welded (laser welded) by irradiating the laser (step 80). As a result, the pedestal member 31 and the pressure applying member 37 are integrated. The details of step 80 will be described later.

(Laser irradiation process)
Subsequently, the protruding portion 315 of the pedestal member 31 is irradiated with a laser in a state where the pedestal member 31 and the pressure applying member 37 are integrated (step 90). As a result, the protruding portion 315 of the pedestal member 31 contracts in the center line direction and is sandwiched between the pedestal member 31 and the pressure applying member 37, so that the first piezoelectric element 341 to the third piezoelectric element constituting the piezoelectric element group 34 are formed. A preload is applied to 343. The details of step 90 will be described later.

(Rear end side electrode welding process)
Next, the facing portion (near the first through hole 321) between the rear end side electrode plate 33 and the rear end side electrode pin 38 is welded (laser welded) by irradiating the laser (step 100).

(Tip side electrode welding process)
Further, the facing portion (near the first through hole 351) between the tip side electrode plate 35 and the tip side electrode pin 39 is welded (laser welded) by irradiating the laser (step 110).

Here, in steps 80 to 110, laser processing can be performed using the same laser oscillator. Examples of lasers that can be used in steps 80 to 110 include solid-state lasers, gas lasers, and semiconductor lasers.

Then, after the various processing by the laser is completed, the detection unit 30 can be obtained by removing the various jigs attached and further removing the jigs from the base.
After that, the pressure detection device 20 can be obtained by attaching the constituent members of the housing unit 40, the transmission unit 50, and the output unit 60 to the detection unit 30 thus obtained.

[Details of laser welding process]
Then, the laser welding process of step 80 described above will be specifically described.
FIG. 11A is a diagram for explaining the laser welding process of step 80.

In the present embodiment, in the detection unit 30 temporarily assembled by each step up to step 70, the pressure applying member 37 is located on the tip side (upper side) of the detection unit 30. Further, the protruding portion 315 of the pedestal member 31 is inserted into the through hole 373 provided in the pressure applying member 37, and the inner peripheral surface of the through hole 373 and the outer peripheral surface of the thick portion 315b in the protruding portion 315 are formed. We are facing each other. Then, in this state, when the detection unit 30 is viewed from the tip side, the inner peripheral surface of the third through hole 313 provided in the pedestal member 31 is exposed.

Then, in step 80, the tip side of the contact portion between the pedestal member 31 and the pressure applying member 37 is irradiated with the laser beam L from the tip side over the entire circumference in the circumferential direction. Then, as the thick portion 315b and the pressure applying member 37 are both melted and solidified at the portion irradiated with the laser beam L, the welded portion 316 is formed over the entire circumference in the circumferential direction. As a result, the pedestal member 31 and the pressure applying member 37 are integrated via the welded portion 316. Here, if the welded portion 316 in which both the thick portion 315b and the pressure applying member 37 are melted and solidified becomes an obstacle when fitting the pressure distribution plate 52 into the recess 372 provided in the pressure applying member 37. , A step of polishing the welded portion 316 may be provided. Further, a step portion having a diameter larger than that of the rear end side of the recess 372 is provided on the tip end side of the recess 372 of the pressure applying member 37 so as to have a space between the pressure distribution plate 52 and the welded portion 316. The pressure distribution plate 52 may be fitted into the pressure distribution plate 52.

[Details of laser irradiation process]
Subsequently, the laser irradiation step of step 90 described above will be specifically described.
FIG. 11B is a diagram for explaining the laser irradiation step of step 90.

In the present embodiment, the welded portion 316 is formed in the detection portion 30 in which the pedestal member 31 and the pressure applying member 37 are welded by the laser welding step of step 80 as described above.

Then, in step 90, among the inner peripheral surfaces of the third through hole 313 provided in the pedestal member 31, the portion of the protruding portion 315 where the thick portion 315b exists, that is, the portion on the tip side of the thin portion 315a. , The laser beam L is irradiated over the entire circumference in the circumferential direction. Then, as the thick portion 315b melts and solidifies in the portion irradiated with the laser beam, irradiation marks 317 are formed over the entire circumference in the circumferential direction. At this time, the protruding portion 315 (thick-walled portion 315b) of the pedestal member 31 contracts in the center line direction with the formation of the irradiation mark 317. Then, in the pedestal member 31 and the pressure applying member 37 integrated with the formation of the welded portion 316, the distance between the front end side surface of the base portion 314 of the pedestal member 31 and the rear end side surface of the pressure applying member 37 is By forming the irradiation mark 317 on the protruding portion 315, the irradiation mark 317 is shorter than before the formation. Then, the piezoelectric element group 34 (first) from the base 314 and the pressure applying member 37 of the pedestal member 31 via the rear end side insulating plate 32, the rear end side electrode plate 33, the front end side insulating plate 36 and the front end side electrode plate 35. The force (preload) applied to the piezoelectric elements 341 to the third piezoelectric element 343) is increased by forming the irradiation marks 317 on the protruding portion 315. By applying a preload to the piezoelectric element group 34 (first piezoelectric element 341 to third piezoelectric element 343) in this way, the first piezoelectric element 341 to the third piezoelectric element 343 do not particularly join. Even in the state, it is stably held by the detection unit 30. In the laser irradiation step of this step 90, the laser irradiation position in the thick portion 315b in the protruding portion 315 until the preload applied to the piezoelectric element group 34 (first piezoelectric element 341 to third piezoelectric element 343) reaches a desired value. Can be changed and performed multiple times. The reason why the thick portion 315b of the protruding portion 315 is set as the laser irradiation position is that when the thin portion 315a of the protruding portion 315 is irradiated with the laser, the thin portion 315a may be damaged by the laser irradiation.

[Summary]
In the present embodiment, in the detection unit 30, the base portion 314 of the pedestal member 31 and the pressure applying member 37 are used, and the rear end side insulating plate 32, the rear end side electrode plate 33, the front end side electrode plate 35, and the front end side insulation are used. The first piezoelectric element 341 to the third piezoelectric element 343 constituting the piezoelectric element group 34 are sandwiched via the plate 36. Further, in the present embodiment, the base portion 314 of the pedestal member 31 and the pressure applying member 37 are provided at positions surrounded by the first piezoelectric element 341 to the third piezoelectric element 343, and the protruding portion of the pedestal member 31 is provided. It was made to connect via 315. Further, the thick portion 315b in the protruding portion 315 and the pressure applying member 37 were integrated via the welded portion 316 by laser welding. Then, by forming an irradiation mark 317 by laser irradiation on the thick portion 315b of the protruding portion 315, the protruding portion 315 is contracted in the center line direction. As a result, the detection unit 30 can apply a preload to the first piezoelectric elements 341 to the third piezoelectric elements 343. Here, in the present embodiment, by arranging the protruding portion 315 that functions as a tension spring in the region inside the first piezoelectric element 341 to the third piezoelectric element 343, the first piezoelectric element 341 to the third piezoelectric element 343 is arranged. The detection unit 30 can be downsized as compared with the case where it is arranged outside the element 343.

Further, in the present embodiment, in the detection unit 30, the tip side insulating plate 36 is arranged for the purpose of electrically insulating the positive path and the housing path, and the negative path and the housing path are electrically isolated. The rear end side insulating plate 32 was arranged for the purpose of insulating. For the front end side insulating plate 36 and the rear end side insulating plate 32, a ceramic material that is mechanically brittle as compared with the metal front end side electrode plate 35 and the rear end side electrode plate 33 was used.

Therefore, the protruding portion 315 of the pedestal member 31 contracts with the formation of the irradiation mark 317, so that the distance between the front end side surface of the base portion 314 of the pedestal member 31 and the rear end side surface of the pressure applying member 37. As the force applied to the front end side insulating plate 36 and the rear end side insulating plate 32 increases, cracks occur in the front end side insulating plate 36 and the rear end side insulating plate 32. Here, if the front end side insulating plate 36 or the rear end side insulating plate 32 is cracked at a portion facing the first piezoelectric element 341 to the third piezoelectric element 343 constituting the piezoelectric element group 34, the first piezoelectric element 341 -The preload applied to the third piezoelectric element 343 may deviate (fluctuate) from the initially planned set value. Further, the holding of the first piezoelectric element 341 to the third piezoelectric element 343 in the detection unit 30 becomes unstable.

On the other hand, in the present embodiment, the tip-side insulating plate 36 is provided with the first groove portion 364 to the third groove portion 366, which are fragile as compared with the flat portion, and the first piezoelectric element 341 avoids the portions facing them. ~ The third piezoelectric element 343 is arranged. Then, the first through hole 361 was formed so as to overlap the first groove portion 364, and the second through hole 362 was formed so as to overlap the second groove portion 365.

Further, in the present embodiment, the rear end side insulating plate 32 is provided with the first groove portion 324 to the third groove portion 326 which are fragile as compared with the flat portion, and the first piezoelectric element 341 to avoid the portions facing these. The third piezoelectric element 343 is arranged. Then, the first through hole 321 was formed so as to overlap the first groove portion 324, and the second through hole 322 was formed so as to overlap the second groove portion 325.

By adopting such a configuration, for example, when the front end side insulating plate 36 is cracked, the relatively fragile first groove portion 364 to third groove portion 366 are likely to serve as a base point. Further, for example, when the rear end side insulating plate 32 is cracked, the relatively fragile first groove portion 324 to third groove portion 326 tends to be a base point. Therefore, in the obtained detection unit 30 and thus the pressure detection device 20, fluctuations in the preload applied to the first piezoelectric element 341 to the third piezoelectric element 343 can be suppressed. Further, the first piezoelectric element 341 to the third piezoelectric element 343 can be held in a stable state.

FIG. 12 is an SEM photograph showing the state of the outer peripheral surfaces of the distal end side electrode plate 35, the distal end side insulating plate 36, and the pressure applying member 37 after the laser irradiation step of step 90.
From FIG. 12, it can be seen that the front end side insulating plate 36 is cracked with the groove portion (any of the first groove portion 324 to the third groove portion 326) as a base point.

Here, in the present embodiment, of the rear end side insulating plate 32 shown in FIG. 9A, the forming surface of the first groove portion 324 to the third groove portion 326 is formed on the piezoelectric element group 34 side (rear end side electrode plate). The forming surface of the first groove portion 364 to the third groove portion 366 of the front end side insulating plate 36 shown in FIG. 9 (b) is directed toward the piezoelectric element group 34 side (rear end side electrode plate 33 side). ), But this is due to the following reasons.

In the detection unit 30, the present inventor has the first groove portion in the detection unit 30, depending on whether the formation surface of the first groove portion 364 to the third groove portion 366 in the front end side insulating plate 36 is directed to the rear end side or the tip end side. A simulation was performed on the difference in the force (force applied in the center line direction) for cracking in the 364 to the third groove 366.

As a result, the force required to cause cracks in the first groove portion 364 to the third groove portion 366 is more than that in the case where the forming surface of the first groove portion 364 to the third groove portion 366 is directed toward the tip side. It was found that the shape of the third groove portion 366 was smaller (cracked with a weaker force) when the forming surface was directed toward the rear end side. Therefore, in the present embodiment, the front end side insulating plate 36 and the rear end side insulating plate 32 are arranged so as to have the above-mentioned positional relationship.

[Other]
In the present embodiment, the pressure detecting device 20 is used for detecting the combustion pressure of the gas turbine engine, but the present invention is not limited to this, and for example, it may be used for detecting the combustion pressure of the reciprocating engine. Absent.

Further, in the present embodiment, the negative electrode side of the piezoelectric element group 34 is arranged on the front end side of the pressure detection device 20, and the positive electrode side of the piezoelectric element group 34 is arranged on the rear end side of the pressure detection device 20. Not limited to this. That is, the positive electrode side of the piezoelectric element group 34 may be arranged on the front end side of the pressure detection device 20, and the negative electrode side of the piezoelectric element group 34 may be arranged on the rear end side of the pressure detection device 20.

Further, in the present embodiment, the number of piezoelectric elements constituting the piezoelectric element group 34 is three, but the number is not limited as long as it is two or more. However, when the piezoelectric element group 34 is composed of three piezoelectric elements (first piezoelectric element 341 to third piezoelectric element 343), three-point support is performed by the first piezoelectric element 341 to the third piezoelectric element 343. Therefore, rattling in the detection unit 30 can be suppressed.

Furthermore, in the present embodiment, the rear end side insulating plate 32 and the front end side insulating plate 36 are each provided with a groove portion and a through hole as fragile portions, but the configuration of the fragile portion is not limited to this. For example, a plurality of through holes may be provided side by side in a cut line shape, or a portion mechanically more fragile than other portions may be provided by chemical treatment or the like.

Then, in the present embodiment, the protruding portion 315 (thick wall portion 315b) of the pedestal member 31 is contracted in the center line direction by irradiating the laser, but the protruding portion 315 is used by using another method. May be contracted.

20 ... Pressure detector, 30 ... Detection unit, 31 ... Pedestal member, 32 ... Rear end side insulating plate, 33 ... Rear end side electrode plate, 34 ... Piezoelectric element group, 35 ... Tip side electrode plate, 36 ... Tip side insulation Plate, 37 ... Pressure applying member, 38 ... Rear end side electrode pin, 39 ... Front end side electrode pin, 40 ... Housing part, 41 ... Front end side housing, 42 ... Rear end side housing, 50 ... Transmission part, 51 ... Diaphragm head, 52 ... Pressure distribution plate, 60 ... Output unit, 61 ... First cable, 62 ... Second cable, 63 ... First connection sleeve, 64 ... Second connection sleeve, 65 ... Cable housing, 66 ... Holding member, 67 ... inclusions, 341 ... first piezoelectric element, 342 ... second piezoelectric element, 343 ... third piezoelectric element

Claims (6)

A plurality of piezoelectric elements that detect changes in pressure from one end side to the other end side using a piezoelectric body,
An electrode member having conductivity and in contact with one end side of each of the plurality of piezoelectric elements,
A support member that supports the plurality of piezoelectric elements via the electrode member,
An insulating member having an insulating property, which is arranged between the electrode member and the support member and is provided with a fragile portion which is fragile as compared with the facing portion, is provided at a portion which does not face the plurality of piezoelectric elements. Including pressure detector. The pressure according to claim 1, wherein the fragile portion provided in the non-opposing portion of the insulating member has a thickness in the direction from one end side to the other end side thinner than that of the facing portion. Detection device. The pressure detecting device according to claim 2, wherein the fragile portion is a recess provided on the other end surface of the insulating member. With other electrode members having conductivity and in contact with the other end side of each of the plurality of piezoelectric elements,
Other insulating members arranged on the other end side of the other electrode member and provided with other fragile portions that are vulnerable to the facing portions at the portions that do not face the piezoelectric element.
Further including the electrode member, a plurality of the piezoelectric elements, the other electrode member, and a sandwiching member for sandwiching the other insulating member, which is arranged on the other end side of the other insulating member. The pressure detecting device according to any one of claims 1 to 3 , wherein the pressure detecting device is characterized. Claim wherein another weak portion provided on the sites that are not the face of the other insulating member, the thickness of the direction from one end to the other end, characterized in that thinner than portions of the opposed 4. The pressure detection device according to 4 . The pressure detecting device according to claim 5 , wherein the other fragile portion is a recess provided on a surface on one end side of the other insulating member.

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